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In this paper data on the number of follicles in testes and the number of ovarioles in ovaries of planthoppers (Hemiptera: Fulgoromorpha) are summarised and discussed. Fulgoromorpha include about 14,000 described species belonging to 21 families distributed throughout the world. The number of follicles is known for 186 species, 123 genera and 17 families, and the number of ovarioles is known for 52 species, 44 genera and 11 families. Almost 80% of the species studied belong to the families Dictyopharidae, Delphacidae, Issidae, Cixiidae and Achilidae. The number of follicles per testis and ovarioles per ovary varies within similar ranges, from 2 to 30 and from 3 to just over 30, respectively. The predominant number of follicles is 6, which is found in more than one third of the species and in almost all of the families studied. This number is considered as an ancestral trait for Fulgoromorpha. In each family, the ancestral number can vary both upwards or downwards, probably due to either polymerization or oligomerization. In the more basal families, a decreasing trend clearly predominates, whereas an increasing trend predominates in the more advanced families. As for the numbers of ovarioles, they tend to vary within families, with rare exceptions (e.g., Dictyopharidae), but that is probably due to the lack of data. [ABSTRACT FROM AUTHOR]

Glycerol dehydrogenase (GDH) catalyzes glycerol oxidation to dihydroxyacetone in a NAD+-dependent manner. As an initiator of the oxidative pathway of glycerol metabolism, a variety of functional and structural studies of GDH have been conducted previously. Structural studies revealed intriguing features of GDH, like the flexible β-hairpin and its significance. Another commonly reported structural feature is the enzyme's octameric oligomerization, though its structural details and functional significance remained unclear. Here, with a newly reported GDH structure, complexed with both NAD+ and glycerol, we analyzed the octamerization of GDH. Structural analyses revealed that octamerization reduces the structural dynamics of the N-domain, which contributes to more consistently maintaining a distance required for catalysis between the cofactor and substrate. This suggests that octamerization may play a key role in increasing the likelihood of the enzyme reaction by maintaining the ligands in an appropriate configuration for catalysis. These findings expand our understanding of the structure of GDH and its relation to the enzyme's activity. [ABSTRACT FROM AUTHOR]

Cullin-RING E3 ubiquitin ligase (CRL) family members play critical roles in numerous biological processes and diseases including cancer and Alzheimer's disease. Oligomerization of CRLs has been reported to be crucial for the regulation of their activities. However, the structural basis for its regulation and mechanism of its oligomerization are not fully known. Here, we present cryo-EM structures of oligomeric CRL2FEM1B in its unneddylated state, neddylated state in complex with BEX2 as well as neddylated state in complex with FNIP1/FLCN. These structures reveal that asymmetric dimerization of N8-CRL2FEM1B is critical for the ubiquitylation of BEX2 while FNIP1/FLCN is ubiquitylated by monomeric CRL2FEM1B. Our data present an example of the asymmetric homo-dimerization of CRL. Taken together, this study sheds light on the ubiquitylation strategy of oligomeric CRL2FEM1B according to substrates with different scales. Synopsis: The structural basis and biological importance of cullin-RING ubiquitin ligase (CRL) oligomerization remain largely unclear. Here, high-resolution cryo-EM and biochemical data reveal that oligomerization of CRL2FEM1B serves as a structural foundation for accommodating substrates of varying sizes. Cryo-EM structures show oligomeric CRL2FEM1B in its unneddylated state and as neddylated form in complex with different substrates. RBX1 and CUL2 participate in the assembly of CRL2FEM1B oligomers. Asymmetric homo-dimerization allows CRL2FEM1B to ubiquitinate substrates with small scales, such as BEX2. Large substrates such as FNIP1/FLCN complexes are ubiquitinated by monomeric CRL2FEM1B. Asymmetric homo-dimerization allows ubiquitination of substrates with small scales, while large substrates are targeted by monomeric CRL2-FEM1B E3. [ABSTRACT FROM AUTHOR]

Hantaan virus is a dangerous human pathogen whose segmented negative-stranded RNA genome is replicated and transcribed by a virally-encoded multi-functional polymerase. Here we describe the complete cryo-electron microscopy structure of Hantaan virus polymerase in several oligomeric forms. Apo polymerase protomers can adopt two drastically different conformations, which assemble into two distinct symmetric homodimers, that can themselves gather to form hexamers. Polymerase dimerization induces the stabilization of most polymerase domains, including the C-terminal domain that contributes the most to dimer's interface, along with a lariat region that participates to the polymerase steadying. Binding to viral RNA induces significant conformational changes resulting in symmetric oligomer disruption and polymerase activation, suggesting the possible involvement of apo multimers as protecting systems that would stabilize the otherwise flexible C-terminal domains. Overall, these results provide insights into the multimerization capability of Hantavirus polymerase and may help to define antiviral compounds to counteract these life-threatening viruses. Hantaan virus polymerase is a central enzyme that performs hantavirus genome replication and transcription. Here, the authors unveil the structure of the full-length Hantaan virus polymerase in monomeric, dimeric and hexameric apo forms, revealing the multimerization capability of this enzyme. [ABSTRACT FROM AUTHOR]

Microbial rhodopsins are retinal membrane proteins that found a broad application in optogenetics. The oligomeric state of rhodopsins is important for their functionality and stability. Of particular interest is the oligomeric state in the cellular native membrane environment. Fluorescence microscopy provides powerful tools to determine the oligomeric state of membrane proteins directly in cells. Among these methods is quantitative photoactivated localization microscopy (qPALM) allowing the investigation of molecular organization at the level of single protein clusters. Here, we apply qPALM to investigate the oligomeric state of the first and most used optogenetic tool Channelrhodopsin‐2 (ChR2) in the plasma membrane of eukaryotic cells. ChR2 appeared predominantly as a dimer in the cell membrane and did not form higher oligomers. The disulfide bonds between Cys34 and Cys36 of adjacent ChR2 monomers were not required for dimer formation and mutations disrupting these bonds resulted in only partial monomerization of ChR2. The monomeric fraction increased when the total concentration of mutant ChR2 in the membrane was low. The dissociation constant was estimated for this partially monomerized mutant ChR2 as 2.2±0.9 proteins/μm2. Our findings are important for understanding the mechanistic basis of ChR2 activity as well as for improving existing and developing future optogenetic tools. [ABSTRACT FROM AUTHOR]

Herein, four catalysts, consisting of either MFI or BEA as the zeolite framework in the presence or absence of Ni, are compared to explore the individual and collective adsorptive and catalytic contributions of pore topology, Ni sites, and acid sites. Both continuous and pulsed chemisorption/reaction experiments are used to obtain a complete picture of the time‐dependent adsorption‐desorption behavior, reaction mechanisms, and deactivation steps. The methodology highlights the effect of acid sites, especially during the initial stages of reaction and in the BEA‐based catalysts, which have higher acidity at a given Si/Al ratio. In addition, Ni accelerates the reaction and improves the selectivity towards intermediate oligomers. However, the tendency for the most active Ni and acid sites to saturate and deactivate more rapidly than the less active ones may lead to misinterpretation when using the continuous reactor alone. Hence, the dominant mechanisms over the different catalyst sites and reaction times are discussed based on the combined steady and dynamic experiments. [ABSTRACT FROM AUTHOR]

Background: Cancer stem-like capacities are major factors contributing to unfavorable prognosis. However, the associated molecular mechanisms underlying cancer stem-like cells (CSCs) maintain remain unclear. This study aimed to investigate the role of the ubiquitin E3 ligase membrane-associated RING-CH 7 (MARCH7) in bladder cancer cell CSCs. Methods: Male BALB/c nude mice aged 4–5 weeks were utilized to generate bladder xenograft model. The expression levels of MARCHs were checked in online databases and our collected bladder tumors by quantitative real-time PCR (q-PCR) and immunohistochemistry (IHC). Next, we evaluated the stem-like capacities of bladder cancer cells with knockdown or overexpression of MARCH7 by assessing their spheroid-forming ability and spheroid size. Additionally, we conducted proliferation, colony formation, and transwell assays to validate the effects of MARCH7 on bladder cancer CSCs. The detailed molecular mechanism of MARCH7/NOD1 was validated by immunoprecipitation, dual luciferase, and in vitro ubiquitination assays. Co-immunoprecipitation experiments revealed that nucleotide-binding oligomerization domain-containing 1 (NOD1) is a substrate of MARCH7. Results: We found that MARCH7 interacts with NOD1, leading to the ubiquitin–proteasome degradation of NOD1. Furthermore, our data suggest that NOD1 significantly enhances stem-like capacities such as proliferation and invasion abilities. The overexpressed MARCH7 counteracts the effects of NOD1 on bladder cancer CSCs in both in vivo and in vitro models. Conclusion: Our findings indicate that MARCH7 functions as a tumor suppressor and inhibits the stem-like capacities of bladder tumor cells by promoting the ubiquitin–proteasome degradation of NOD1. Targeting the MARCH7/NOD1 pathway could be a promising therapeutic strategy for bladder cancer patients. [ABSTRACT FROM AUTHOR]

The prevailing model of steroid hormone nuclear receptor function assumes ligand‐induced homodimer formation followed by binding to DNA hormone response elements (HREs). This model has been challenged by evidence showing that the glucocorticoid receptor (GR) forms tetramers upon ligand and DNA binding, which then drive receptor‐mediated gene transactivation and transrepression. GR and the closely‐related mineralocorticoid receptors (MR) interact to transduce corticosteroid hormone signaling, but whether they share the same quaternary arrangement is unknown. Here, we used a fluorescence imaging technique, Number & Brightness, to study oligomerization in a cell system allowing real‐time analysis of receptor‐DNA interactions. Agonist‐bound MR forms tetramers in the nucleoplasm and higher order oligomers upon binding to HREs. Antagonists form intermediate‐size quaternary arrangements, suggesting that large oligomers are essential for function. Divergence between MR and GR quaternary structure is driven by different functionality of known and new multimerization interfaces, which does not preclude formation of heteromers. Thus, influencing oligomerization may be important to selectively modulate corticosteroid signaling. [ABSTRACT FROM AUTHOR]

The dynamin-related human guanylate-binding protein 1 (GBP1) mediates host defenses against microbial pathogens. Upon GTP binding and hydrolysis, auto-inhibited GBP1 monomers dimerize and assemble into soluble and membrane-bound oligomers, which are crucial for innate immune responses. How higher-order GBP1 oligomers are built from dimers, and how assembly is coordinated with nucleotide-dependent conformational changes, has remained elusive. Here, we present cryo-electron microscopy-based structural data of soluble and membrane-bound GBP1 oligomers, which show that GBP1 assembles in an outstretched dimeric conformation. We identify a surface-exposed helix in the large GTPase domain that contributes to the oligomerization interface, and we probe its nucleotide- and dimerization-dependent movements that facilitate the formation of an antimicrobial protein coat on a gram-negative bacterial pathogen. Our results reveal a sophisticated activation mechanism for GBP1, in which nucleotide-dependent structural changes coordinate dimerization, oligomerization, and membrane binding to allow encapsulation of pathogens within an antimicrobial protein coat. Synopsis: Oligomerization of the human guanylate-binding protein 1 (GBP1) mediates innate immune responses against bacterial pathogens. Here, structural analyses combined with biochemical experiments explain how nucleotide-dependent structural changes coordinate GBP1 oligomerization toward the formation of an antimicrobial protein coat. Cryo-EM shows that GBP1 assembles in an outstretched dimeric conformation to form soluble polymers and membrane-bound oligomers. The peripheral helix α4' in the large GTPase domain is critical for establishing the oligomeric interface. Nucleotide-dependent structural changes coordinate GBP1 oligomerization and membrane binding to allow encapsulation of pathogens. GBP1 oligomerization and membrane binding are coordinated by nucleotide-dependent structural changes, facilitating the formation of a protein coat around bacteria. [ABSTRACT FROM AUTHOR]

Cuproptosis is a recently discovered form of cell death that is mediated by copper (Cu) and is a non-apoptotic form of cell death related to oligomerization of lipoylated proteins and loss of Fe-S protein clusters. Since its discovery, cuproptosis has been extensively studied by researchers for its mechanism and potential applications in the treatment of cancer. Therefore, this article reviews the specific mechanism of cuproptosis currently studied, as well as its principles and strategies for use in anti-cancer treatment, with the aim of providing a reference for cuproptosis-based cancer therapy. [ABSTRACT FROM AUTHOR]

Gasdermin D (GSDMD) serves as a vital mediator of inflammasome-driven pyroptosis. In our study, we have identified NU6300 as a specific GSDMD inhibitor that covalently interacts with cysteine-191 of GSDMD, effectively blocking its cleavage while not affecting earlier steps such as ASC oligomerization and caspase-1 processing in AIM2-and NLRC4-mediated inflammation. On the contrary, NU6300 robustly inhibits these earlier steps in NLRP3 inflammasome, confirming a unique feedback inhibition effect in the NLRP3-GSDMD pathway upon GSDMD targeting. Our study reveals a previously undefined mechanism of GSDMD inhibitors: NU6300 impairs the palmitoylation of both full-length and N-terminal GSDMD, impeding the membrane localization and oligomerization of N-terminal GSDMD. In vivo studies further demonstrate the efficacy of NU6300 in ameliorating dextran sodium sulfate-induced colitis and improving survival in lipopolysaccharide-induced sepsis. Overall, these findings highlight the potential of NU6300 as a promising lead compound for the treatment of inflammatory diseases. [ABSTRACT FROM AUTHOR]

In contrast to prevalent strategies which make use of β-sheet mimetics to block Aβ fibrillar growth, in this study, we designed a series of sulfonyl-γ-AApeptide helices that targeted the crucial α-helix domain of Aβ13-26 and stabilized Aβ conformation to avoid forming the neurotoxic Aβ oligomeric β-sheets. Biophysical assays such as amyloid kinetics and TEM demonstrated that the Aβ oligomerization and fibrillation could be greatly prevented and even reversed in the presence of sulfonyl-γ-AApeptides in a sequence-specific and dose-dependent manner. The studies based on circular dichroism, Two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) spectra unambiguously suggested that the sulfonyl-γ-AApeptide Ab-6 could bind to the central region of Aβ42 and induce α-helix conformation in Aβ. Additionally, Electrospray ionisation-ion mobility spectrometry–mass spectrometry (ESI-IMS-MS) was employed to rule out a colloidal mechanism of inhibitor and clearly supported the capability of Ab-6 for inhibiting the formation of Aβ aggregated forms. Furthermore, Ab-6 could rescue neuroblastoma cells by eradicating Aβ-mediated cytotoxicity even in the presence of pre-formed Aβ aggregates. The confocal microscopy demonstrated that Ab-6 could still specifically bind Aβ42 and colocalize into mitochondria in the cellular environment, suggesting the rescue of cell viability might be due to the protection of mitochondrial function otherwise impaired by Aβ42 aggregation. Taken together, our studies indicated that sulfonyl-γ-AApeptides as helical peptidomimetics could direct Aβ into the off-pathway helical secondary structure, thereby preventing the formation of Aβ oligomerization, fibrillation and rescuing Aβ induced cell cytotoxicity. [ABSTRACT FROM AUTHOR]

Here, we report on the synthesis of discrete oligomers of alkyl‐bridged naphthalenediimides (NDIs) and study their molecular nanostructures both in bulk, in solution, and at the liquid‐solid interface. Via an iterative synthesis method, multiple NDI cores were bridged with short and saturated alkyl‐diamines (C3 and C12) or long and unsaturated alkyl‐diamines (u2C33 to u8C100) at their imide termini. The strong intermolecular interaction between the NDI cores was observed by probing their photophysical properties in solution. In bulk, the discrete NDI oligomers preferentially ordered in lamellar morphologies, irrespective of whether a saturated or unsaturated spacer was employed. Moreover, both the molecular architecture as well as the crystallization conditions play a significant role in the nanoscale ordering. The long unsaturated alkyl chains lead preferably to folded‐chain conformations while their saturated analogues form stretched arrangements. At the solution‐solid interface, well‐defined lamellar regions were observed. These results show that precision in chemical structure alone is not sufficient to reach well‐defined structures of discrete oligomers, but that it must be combined with precision in processing conditions. [ABSTRACT FROM AUTHOR]

Arene‐formaldehyde condensation is a versatile reaction for producing various oligomeric/polymeric materials. However, the precise control of oligomerization degree is still challenging because the starting materials and intermediates have similar reactivities. Here, we demonstrate the selective synthesis of a methylene‐bridged arene trimer using the confined cavity of a coordination cage. The limited space of the cavity prevents unregulated polymerization. The confinement effect for the kinetic protection is also demonstrated by the subsequent site‐selective iodination of the trimer product within the cage. [ABSTRACT FROM AUTHOR]

It has been shown in tests that N-heteroaryl-substituted α-diphenylphosphinoglycines, namely, N-(pyrazin-2-yl) α-diphenylphosphinoglycine, N-(pyridin-2-yl) α-diphenylphosphinoglycine, and N‑(pyrimidin-2-yl) α-diphenylphosphinoglycine, which are synthesized by the three-component condensation of diphenylphosphine, the respective primary amine, and glyoxylic acid monohydrate, being combined with Ni(COD)2, where COD is cyclooctadiene-1,5, are capable of generating active forms of catalysts for the selective homogeneous dimerization and trimerization of ethylene to form butene-1 and hexene-1 as the main products. The studied organonichel catalyst systems provide a yield of short-chain (C4–C6) olefins at a level of 90% with a linear α-olefin selectivity of 97%. Studies of the effect of temperature on the homogeneous oligomerization of ethylene using the synthesized compounds have revealed that the process run at an optimum temperature of 80–105°C and an optimum ethylene pressure of 20–35 atm provides the highest butene-1 and hexene-1 selectivity. Under these conditions, the butene selectivity is recorded at a level of 71.4–72.6% (butene-1 selectivity of 69.3–71.1%), while the hexene selectivity is 20.6–21.2% (hexene-1 selectivity of 19.2–19.5%). The optimum duration of the oligomerization process at a temperature of 105°C is 1.5 h. The butene-1 and hexene-1 formation rate is 168.1 and 47.3 golig h–1, respectively. [ABSTRACT FROM AUTHOR]

This document is a compilation of various research articles and journals that provide information on the characteristics, synthesis methods, and applications of Fe2O3 (iron sand) nanoparticles. The articles discuss the unique magnetic properties of iron sand and its potential use in industries such as electronics, energy, chemical, and biomedicine. They explore different synthesis methods, including coprecipitation and hydrothermal methods, to produce hematite nanoparticles from iron sand. The articles also highlight the diverse applications of hematite nanoparticles in water treatment, catalysis, energy storage, electronics, optics, and medical imaging. Additionally, the document includes articles that analyze the mineral content, electrical properties, and magnetic properties of iron sand, as well as its potential use in drug delivery and environmental remediation. Overall, these articles provide valuable insights into the properties and potential applications of iron sand and its derived materials. [Extracted from the article]

A series of N, N' bis(pyridine-imine) Schiff base late transition metal (Fe, Co, and Ni) complexes with different ligand structures and catalytic active sites were synthesized. Ethylene oligomerization results showed that bis(pyridine-imine) iron complex had the highest catalytic activity (10.8 × 105 g/mol Fe h), and the catalytic activity of cobalt complex was the lowest (2.5 × 105 g/mol Co h); nickel complex had the highest selectivity toward high carbon olefins (28.6%), while the iron complex had the lowest (0.2%). The structure-activity relationship between the catalyst structure and catalytic properties for ethylene oligomerization was further studied by density functional theory (DFT) calculations. The bis(pyridine-imine) iron complex had the highest energy gap value and the most stable catalyst structure, which was more conducive to oligomerization; and the N–M–N bond of the nickel complex had the smallest bond angle, which was beneficial for chain growth. Based on the Cossee mechanism, a mechanism for ethylene oligomerization catalyzed by bis(pyridine-imine) metal complexes was proposed. To further study the micro reaction process of ethylene oligomerization, a molecular model of pyridine imine nickel complex and its catalytic ethylene oligomerization reaction path were proposed. The structure and energy of the reaction intermediate and transition state were calculated using DFT. The molecular model of the nickel complex had a lower ethylene insertion barrier and β-H elimination of energy barriers, indicating that the molecular model of the pyridine imine nickel complex had ethylene oligomerization active centers. [ABSTRACT FROM AUTHOR]

Nucleotide-binding oligomerization domain-like (NOD) receptors rely on the interface between immunity and metabolism. Dietary factors constitute critical players in the activation of innate immunity and modulation of the gut microbiota. The latter have been involved in worsening or improving the control and promotion of diseases such as obesity, type 2 diabetes, metabolic syndrome, diseases known as non-communicable metabolic diseases (NCDs), and the risk of developing cancer. Intracellular NODs play key coordinated actions with innate immune 'Toll-like' receptors leading to a diverse array of gene expressions that initiate inflammatory and immune responses. There has been an improvement in the understanding of the molecular and genetic implications of these receptors in, among others, such aspects as resting energy expenditure, insulin resistance, and cell proliferation. Genetic factors and polymorphisms of the receptors are determinants of the risk and severity of NCDs and cancer, and it is conceivable that dietary factors may have significant differential consequences depending on them. Host factors are difficult to influence, while environmental factors are predominant and approachable with a preventive and/or therapeutic intention in obesity, T2D, and cancer. However, beyond the recognition of the activation of NODs by peptidoglycan as its prototypical agonist, the underlying molecular response(s) and its consequences on these diseases remain ill-defined. Metabolic (re)programming is a hallmark of NCDs and cancer in which nutritional strategies might play a key role in preventing the unprecedented expansion of these diseases. A better understanding of the participation and effects of immunonutritional dietary ingredients can boost integrative knowledge fostering interdisciplinary science between nutritional precision and personalized medicine against cancer. This review summarizes the current evidence concerning the relationship(s) and consequences of NODs on immune and metabolic health. [ABSTRACT FROM AUTHOR]

The work investigated the synthesis of the oligomers with citric acid (CA) and epoxidized soybean oils (ESO) at various temperatures and the effects of the oligomers on the structures and properties of starch‐based bioplastics. CA was bonded effectively onto ESO via ring‐opening polymerization at 90°C as confirmed by the results of Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and carboxylic group contents of CA‐ESO oligomers (CESO). The oligomers exhibited higher thermal stability than ESO. Regarding starch‐based bioplastics, CESO disrupted the hydrogen bonding interaction within starch molecules and formed the esterification reaction with starch. The bioplastics containing CESO exhibited remarkably higher structural homogeneity and opacity as the synthesis temperatures of CESO increased. However, the thermal properties of the bioplastics with various CESO reduced, which might be due to the decomposition of starch by CESO. The films containing CESO also exhibited lower tensile strength than the film with ESO, which might be related to the decomposition, crosslinking, and plasticization effects of CESO on starch. The bioplastics with CESO exhibited lower degradation due to a more intense interaction of CESO and starch. The study demonstrated the potential of CA as an interfacial linker of starch/ESO‐based bioplastics by adjusting the synthetic temperatures of CESO. [ABSTRACT FROM AUTHOR]

In the field of polymers and organometallic chemistry, a significant gap is apparent in the area of research on well‐defined metal complexes targeted for using in catalysis leading to olefinic oligomers and polymers. Here, we report on the use in these processes the dipicolinate oxovanadium(IV) complexes, without and with auxiliary ligands, i. e. 1,10‐phenanthroline and 2,2'‐bipyridine. The investigated complexes turned out to be versatile precatalysts. After reaction with appropriate activator, they exhibited 11 times higher a catalytic activity than reference vanadium(IV) complexes with salen ligands – so far, precatalysts from a group of vanadium(IV) complexes with the highest known catalytic activity for polymerization of ethylene. In the case of the oligomerization of polar monomers (2‐chloro‐2‐propen‐1‐ol and 3‐buten‐2‐ol) the complexes described in this report have a catalytic activity (very high) similar to vanadium(IV) complexes known in the literature. [ABSTRACT FROM AUTHOR]

Open Reading Frame 6 (ORF6) proteins, which are unique to severe acute respiratory syndrome-related (SARS) coronavirus, inhibit the classical nuclear import pathway to antagonize host antiviral responses. Several alternative models were proposed to explain the inhibitory function of ORF6 [H. Xia et al., Cell Rep. 33, 108234 (2020); L. Miorin et al., Proc. Natl. Acad. Sci. U.S.A. 117, 28344-28354 (2020); and M. Frieman et al., J. Virol. 81, 9812-9824 (2007)]. To distinguish these models and build quantitative understanding of ORF6 function, we developed a method for scoring both ORF6 concentration and functional effect in single living cells. We combined quantification of untagged ORF6 expression level in single cells with optogenetics-based measurement of nuclear transport kinetics, using methods that could be adapted to measure concentration-dependent effects of any untagged protein. We found that SARS-CoV-2 ORF6 is ~15 times more potent than SARS-CoV-1 ORF6 in inhibiting nuclear import and export, due to differences in the C-terminal region that is required for the NUP98-RAE1 binding. The N-terminal region was required for transport inhibition. This region binds membranes but could be replaced by synthetic constructs which forced oligomerization in solution, suggesting its primary function is oligomerization. We propose that the hydrophobic N-terminal region drives oligomerization of ORF6 to multivalently cross-link the NUP98-RAE1 complexes at the nuclear pore complex, and this multivalent binding inhibits bidirectional transport. [ABSTRACT FROM AUTHOR]

Recently, it was shown that Piers' borane [HB(C6F5)2]2 can induce rapid oligomerization reactions of arylacetylenes and arylallenes. Using phenylallene PhCH=C=CH2 and phenylacetylene PhCCH as typical substrates, the detailed mechanisms of borane‐induced oligomerization are disclosed by extensive state‐of‐the‐art DFT calculations. Following initial regioselective hydroboration of unsaturated C=C or C≡C bonds, further oligomerization and structural rearrangement reactions may occur through unique boryl‐enabled conversions such as 1,3‐boryl‐shift, allylboration, 1,2‐carboboration, and 1,5‐electrocyclization. Together with stepwise transborylation with hydroboranes such as pinacolborane HBpin, such fundamental reactions may pave a catalytic way to borane‐induced oligomerization of arylacetylenes and arylallenes. [ABSTRACT FROM AUTHOR]

The possibility of using TiO2‐based compositions: individual and sulfated titania, and their composites with carbon nanotubes as catalysts for glycerol oligomerization has been displayed. The effect of modification of TiO2 with sulfur and carbon nanotubes on acid‐base and catalytic characteristics in the glycerol conversion was investigated. The activation of glycerol on the catalysts has been studied using attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy. Only the samples based on sulfated titania are active over glycerol transformation, showing up to 58.7 % conversion. This is explained by the presence of strong base sites. Glycerides up to pentaglycerides, both linear and nonlinear structure are formed by glycerol oligomerization over TiO2−S. The addition of nanotubes to the catalyst reduces both the glycerol conversion (up to 10.5 %) and the yield of glycerides. However, the spectrum of the resulting products is significantly narrowed, increasing the selectivity for short‐chain glycerides: the portion of diglycerides reaches 72 %, and triglycerides 21 %. Herewith, glycerides of a linear structure only formed. [ABSTRACT FROM AUTHOR]

Dimers and oligomers of alkenes represent a category of compounds that are in great demand in diverse industrial sectors. Among the developing synthetic methods, the catalysis of alkene dimerization and oligomerization using transition metal salts and complexes is of undoubted interest for practical applications. This approach demonstrates substantial potential, offering not only elevated reaction rates but also precise control over the chemo-, regio-, and stereoselectivity of the reactions. In this review, we discuss the data on catalytic systems for alkene dimerization and oligomerization. Our focus lies in the analysis of how the activity and chemoselectivity of these catalytic systems are influenced by various factors, such as the nature of the transition metal, the ligand environment, the activator, and the substrate structure. Notably, this review particularly discusses reaction mechanisms, encompassing metal complex activation, structural and dynamic features, and the reactivity of hydride intermediates, which serve as potential catalytically active centers in alkene dimerization and oligomerization. [ABSTRACT FROM AUTHOR]

Activity-regulated cytoskeleton-associated protein (Arc) plays essential roles in diverse forms of synaptic plasticity, including long-term potentiation (LTP), long-term depression (LTD), and homeostatic plasticity. In addition, it assembles into virus-like particles that may deliver mRNAs and/or other cargo between neurons and neighboring cells. Considering this broad range of activities, it is not surprising that Arc is subject to regulation by multiple types of post-translational modification, including phosphorylation, palmitoylation, SUMOylation, ubiquitylation, and acetylation. Here we explore the potential regulatory role of Arc phosphorylation by protein kinase C (PKC), which occurs on serines 84 and 90 within an α-helical segment in the N-terminal domain. To mimic the effect of PKC phosphorylation, we mutated the two serines to negatively charged glutamic acid. A consequence of introducing these phosphomimetic mutations is the almost complete inhibition of Arc palmitoylation, which occurs on nearby cysteines and contributes to synaptic weakening. The mutations also inhibit the binding of nucleic acids and destabilize high-order Arc oligomers. Thus, PKC phosphorylation of Arc may limit the full expression of LTD and may suppress the interneuronal transport of mRNAs. [ABSTRACT FROM AUTHOR]

Oligomeric acceptors are an effective π‐conjugate extension for small molecules because they effectively combine the advantages of polymeric and small molecular acceptors. The choice of linker group and oligomer position is however crucial for the efficient expression of π‐expansion advantages. Here, vinylene is chosen as the linker group and three oligomeric acceptors are produced with different connecting positions or end‐groups. Under illumination, the dimer acceptor dBTIC‐γV‐BO achieves the best power conversion efficiencies of 17.14% and a T80 lifetime of 2150 h amongst quasi‐planar heterojunction devices, which are much higher and more stable than the directly connected dimers dBTICγ‐EH or dBTIC‐δV‐BO. These results indicate that the oligomerization of small molecules with an appropriate linker group in the γ‐position is an effective strategy with which to improve the photovoltaic performance and stability of organic solar cells, and significantly promote their commercialization. [ABSTRACT FROM AUTHOR]

Highly sulfated malto-oligomers, similar to heparin and heparan-sulfate, have good antiviral, antimetastatic, anti-inflammatory and cell growth inhibitory effects. Due to their broad biological activities and simple structure, sulfated malto-oligomer derivatives have a great therapeutic potential, therefore, the development of efficient synthesis methods for their production is of utmost importance. In this work, preparation of α-(1→4)-linked oligoglucosides containing a sulfonatomethyl moiety at position C-6 of each glucose unit was studied by different approaches. Malto-oligomeric sulfonic acid derivatives up to dodecasaccharides were prepared by polymerization using different protecting groups, and the composition of the product mixtures was analyzed by MALDI-MS methods and size-exclusion chromatography. Synthesis of lower oligomers was also accomplished by stepwise and block synthetic methods, and then the oligosaccharide products were persulfated. The antiviral, anti-inflammatory and cell growth inhibitory activity of the fully sulfated malto-oligosaccharide sulfonic acids were determined by in vitro tests. Four tested di- and trisaccharide sulfonic acids effectively inhibited the activation of the TNF-α-mediated inflammatory pathway without showing cytotoxicity. [ABSTRACT FROM AUTHOR]

Hepcidin, a peptide hormone that negatively regulates iron metabolism, is expressed by bone morphogenetic protein (BMP) signaling. Erythroferrone (ERFE) is an extracellular protein that binds and inhibits BMP ligands, thus positively regulating iron import by indirectly suppressing hepcidin. This allows for rapid erythrocyte regeneration after blood loss. ERFE belongs to the C1Q/TNF-related protein family and is suggested to adopt multiple oligomeric forms: a trimer, a hexamer, and a high molecular weight species. The molecular basis for how ERFE binds BMP ligands and how the different oligomeric states impact BMP inhibition are poorly understood. In this study, we demonstrated that ERFE activity is dependent on the presence of stable dimeric or trimeric ERFE and that larger species are dispensable for BMP inhibition. Additionally, we used an in silico approach to identify a helix, termed the ligand-binding domain, that was predicted to bind BMPs and occlude the type I receptor pocket. We provide evidence that the ligand-binding domain is crucial for activity through luciferase assays and surface plasmon resonance analysis. Our findings provide new insight into how ERFE oligomerization impacts BMP inhibition, while identifying critical molecular features of ERFE essential for binding BMP ligands. [ABSTRACT FROM AUTHOR]

This review highlights the advances in the synthesis of morpholine building blocks useful for artificial oligomers synthesis and peptide foldamers or biopolymers. Both morpholino nucleosides and morpholine derived from amino acids have been considered focusing on the preparation of antisense strands, peptides and bio‐based materials. [ABSTRACT FROM AUTHOR]

Bcl2-associated athanogene 3 (BAG3) is a multifunctional cochaperone responsible for protein quality control within cells. BAG3 interacts with chaperones HSPB8 and Hsp70 to transport misfolded proteins to the Microtubule Organizing Center (MTOC) and degrade them in autophagosomes in a process known as Chaperone Assisted Selective Autophagy (CASA). Mutations in the second conserved IPV motif of BAG3 are known to cause Dilated Cardiomyopathy (DCM) by inhibiting adequate removal of non-native proteins. The proline 209 to leucine (P209L) BAG3 mutant in particular causes the aggregation of BAG3 and misfolded proteins as well as the sequestration of essential chaperones. The exact mechanisms of protein aggregation in DCM are unknown. However, the similar presence of insoluble protein aggregates in Charcot-Marie-Tooth disease type 2 (CMT2) induced by the proline 182 to leucine (P182L) HSPB1 mutant points to a possible avenue for future research: IPV motif. In this review, we summarize the molecular mechanisms of CASA and the currently known pathological effects of mutated BAG3 in DCM. Additionally, we will provide insight on the importance of the IPV motif in protein aggregation by analyzing a potential association between DCM and CMT2.

Different tauopathies are characterized by the isoform-specific composition of the aggregates found in the brain and by structurally distinct tau strains. Although tau oligomers have been implicated as important neurotoxic species, little is known about how the primary structures of the six human tau isoforms affect tau oligomerization because the oligomers are metastable and difficult to analyze. To address this knowledge gap, here, we analyzed the initial oligomers formed by the six tau isoforms in the absence of posttranslational modifications or other manipulations using dot blots probed by an oligomer-specific antibody, native-PAGE/western blots, photo-induced cross-linking of unmodified proteins, mass-spectrometry, and ion-mobility spectroscopy. We found that under these conditions, three-repeat (3R) isoforms are more prone than four-repeat (4R) isoforms to form oligomers. We also tested whether known inhibitors of tau aggregation affect its oligomerization using three small molecules representing different classes of tau aggregation inhibitors, Methylene Blue (MB), the molecular tweezer CLR01, and the all-D peptide TLKIVW, for their ability to inhibit or modulate the oligomerization of the six tau isoforms. Unlike their reported inhibitory effect on tau fibrillation, the inhibitors had little or no effect on the initial oligomerization. Our study provides novel insight into the primary-quaternary structure relationship of human tau and suggests that 3R-tau oligomers may be an important target for future development of compounds targeting pathological tau assemblies.

Three recent publications by Du et al., 1 Balasubramanian et al., 2 and Zhang et al. 3 identified palmitoylation on cysteine 191/192 in gasdermin D as a key determinant of gasdermin D membrane translocation and oligomerization, ensuring efficient plasma membrane permeabilization during pyroptosis. Three recent publications by Du et al.,1 Balasubramanian et al.,2 and Zhang et al.3 identified palmitoylation on cysteine 191/192 in gasdermin D as a key determinant of gasdermin D membrane translocation and oligomerization, ensuring efficient plasma membrane permeabilization during pyroptosis. [ABSTRACT FROM AUTHOR]

In the article, an ionic liquid catalytic system based on diethylamine hydrochloride and aluminum chloride (AlCl3), which meets the concepts of "Green Chemistry," is synthesized as an object of study. The process of 1 - octene oligomerization was carried out in the presence of synthesized ionic liquid catalyst systems. The structure, chemical composition and physicochemical properties of fractions obtained by oligomerization were studied. As a result of experimental studies, fractions above 3500C were obtained and have high quality indicators. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) imaging enables the visualization of protein molecules with high resolution, providing insights into their shape, size, and surface topography. Here, we use AFM to study the aggregation process of protein S100A9 in physiological conditions, in the presence of calcium at a molar ratio 4Ca2+:S100A9. We find that S100A9 readily assembles into a worm-like fibril, with a period dimension along the fibril axis of 11.5 nm. The fibril’s chain length extends up to 136 periods after an incubation time of 144 h. At room temperature, the fibril’s bending stiffness was found to be 2.95×10−28 Nm2, indicating that the fibrils are relatively flexible. Additionally, the values obtained for the Young’s modulus (Ex=6.96×105 Pa and Ey=3.37×105 Pa) are four orders of magnitude lower than those typically reported for canonical amyloid fibrils. Our findings suggest that, under the investigated conditions, a distinct aggregation mechanism may be in place in the presence of calcium. Therefore, the findings reported here could have implications for the field of biomedicine, particularly with regard to Alzheimer’s disease.

Pathogenic Bacillus and clostridial (i.e., Clostridium and Clostridioides) bacteria express a diverse repertoire of effector proteins to promote disease. This includes production of binary toxins, which enter host epithelial cells and seriously damage the intestinal tracts of insects, animals, and humans. In particular, binary toxins form an AB-type complex composed of a catalytic subunit that is toxic (A) and an oligomeric cell-binding and delivery subunit (B), where upon delivery of A into the cytoplasm of the host cell it catalytically ADP-ribosylates actin and rapidly induces host cell death. In this review, binary toxins expressed by Bacillus thuringiensis, Clostridioides difficile, and Clostridium perfringens will be discussed, with particular focus placed upon the structural elucidations of their respective B subunits and how these findings help to deconvolute how toxic enzyme delivery into target host cells is achieved by these deadly bacteria.

The oligomerization of light olefins is an alternative for generating clean liquid fuels. In this study, the MCM-22 zeolite featuring a partially disordered layered structure with framework combined 10 membered ring (10 MR) was discussed for 1-hexene oligomerization. MCM-22 and Y zeolite were compared to investigate the influences of the framework and acidity strength on the activity and yield in the 1-hexene oligomerization. The results indicated that the MCM-22 zeolite was an efficient catalyst for oligomerization compared to Y zeolite. The MCM-22 zeolite was characterized in detail by NMR, Py-FTIR, and TG analyses. The catalytic performance and deactivation properties of MCM-22 zeolite in the oligomerization reaction of 1-hexene were investigated. Structure–activity relationships were established through the kinetic study. Although the density of strong acid sites was essential for the oligomerization of 1-hexene, the presence of low pressure was also necessary for the formation of dimers. Thus, MCM-22 zeolite demonstrates a substantial improvement in initial conversion and catalyst lifespan for 1-hexene oligomerization.

Abstract While certain inorganic main‐group polymers such as silicones (polysiloxanes) are ubiquitous in our everyday life, poly(iminoborane)s have been elusive for a long time. Incorporation of heterocyclic building blocks into their backbone has recently enabled access to the first derivatives of this inorganic‐polymer class, as this approach effectively prevents undesired side‐reactions to borazines. Information about the microstructure of these cyclolinear macromolecules, however, has been scarce. Herein, we present the synthesis of a series of monodisperse oligomers with up to 7 boron and 8 nitrogen atoms, representing the longest well‐defined molecular [>B=N

TRAIL (TNF-related apoptosis-inducing ligand) is a potent inducer of tumor cell apoptosis through TRAIL receptors. While it has been previously pursued as a potential anti-tumor therapy, the enthusiasm subsided due to unsuccessful clinical trials and the fact that many tumors are resistant to TRAIL. In this report, we identified heparan sulfate (HS) as an important regulator of TRAIL-induced apoptosis. TRAIL binds HS with high affinity (KD = 73 nM) and HS induces TRAIL to form higher-order oligomers. The HS-binding site of TRAIL is located at the N-terminus of soluble TRAIL, which includes three basic residues. Binding to cell surface HS plays an essential role in promoting the apoptotic activity of TRAIL in both breast cancer and myeloma cells, and this promoting effect can be blocked by heparin, which is commonly administered to cancer patients. We also quantified HS content in several lines of myeloma cells and found that the cell line showing the most resistance to TRAIL has the least expression of HS, which suggests that HS expression in tumor cells could play a role in regulating sensitivity towards TRAIL. We also discovered that death receptor 5 (DR5), TRAIL, and HS can form a ternary complex and that cell surface HS plays an active role in promoting TRAIL-induced cellular internalization of DR5. Combined, our study suggests that TRAIL-HS interactions could play multiple roles in regulating the apoptotic potency of TRAIL and might be an important point of consideration when designing future TRAIL-based anti-tumor therapy.

The cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) signaling pathway plays a critical protective role against viral infections. Metazoan STING undergoes multilayers of regulation to ensure specific signal transduction. However, the mechanisms underlying the regulation of bacterial STING remain unclear. In this study, we determined the crystal structure of anti-parallel dimeric form of bacterial STING, which keeps itself in an inactive state by preventing cyclic dinucleotides access. Conformational transition between inactive and active states of bacterial STINGs provides an on-off switch for downstream signaling. Some bacterial STINGs living in extreme environment contain an insertion sequence, which we show codes for an additional long lid that covers the ligand-binding pocket. This lid helps regulate anti-phage activities. Furthermore, bacterial STING can bind cyclic di-AMP in a triangle-shaped conformation via a more compact ligand-binding pocket, forming spiral-shaped protofibrils and higher-order fibril filaments. Based on the differences between cyclic-dinucleotide recognition, oligomerization, and downstream activation of different bacterial STINGs, we proposed a model to explain structure-function evolution of bacterial STINGs. Here the authors present the crystal structure of a bacterial STING. The structure shows that bacterial STING can modulate immune responses by forming anti-parallel dimers or, in certain species, through the presence of a long lid. [ABSTRACT FROM AUTHOR]

Mitochondrial apoptotic signaling cascades lead to the formation of the apoptosome, a 1.1-MDa heptameric protein scaffold that recruits and activates the caspase-9 protease. Once activated, caspase-9 cleaves and activates downstream effector caspases, triggering the onset of cell death through caspase-mediated proteolysis of cellular proteins. Failure to activate caspase-9 enables the evasion of programmed cell death, which occurs in various forms of cancer. Despite the critical apoptotic function of caspase-9, the structural mechanism by which it is activated on the apoptosome has remained elusive. Here, we used a combination of methyl-transverse relaxation-optimized NMR spectroscopy, protein engineering, and biochemical assays to study the activation of caspase-9 bound to the apoptosome. In the absence of peptide substrate, we observed that both caspase-9 and its isolated protease domain (PD) only very weakly dimerize with dissociation constants in the millimolar range. Methyl-NMR spectra of isotope-labeled caspase-9, within the 1.3-MDa native apoptosome complex or an engineered 480-kDa apoptosome mimic, reveal that the caspase-9 PD remains monomeric after recruitment to the scaffold. Binding to the apoptosome, therefore, organizes caspase-9 PDs so that they can rapidly and extensively dimerize only when substrate is present, providing an important layer in the regulation of caspase-9 activation. Our work highlights the unique role of NMR spectroscopy to structurally characterize protein domains that are flexibly tethered to large scaffolds, even in cases where the molecular targets are in excess of 1 MDa, as in the present example. [ABSTRACT FROM AUTHOR]

The septin family of eukaryotic proteins comprises distinct classes of sequencerelated monomers that associate in a defined order into linear hetero-oligomers, which are capable of polymerizing into cytoskeletal filaments. Like actin and ⍺ and β tubulin, most septin monomers require binding of a nucleotide at a monomermonomer interface (the septin “G” interface) for assembly into higher-order structures. Like ⍺ and β tubulin, where GTP is bound by both subunits but only the GTP at the ⍺–β interface is subject to hydrolysis, the capacity of certain septin monomers to hydrolyze their bound GTP has been lost during evolution. Thus, within septin hetero-oligomers and filaments, certain monomers remain permanently GTP-bound. Unlike tubulins, loss of septin GTPase activity–creating septin “pseudoGTPases”—occurred multiple times in independent evolutionary trajectories, accompanied in some cases by nonconservative substitutions in highly conserved residues in the nucleotidebinding pocket. Here, we used recent septin crystal structures, AlphaFoldgenerated models, phylogenetics and in silico nucleotide docking to investigate how in some organisms the septin G interface evolved to accommodate changes in nucleotide occupancy. Our analysis suggests that yeast septin monomers expressed only during meiosis and sporulation, when GTP is scarce, are evolving rapidly and might not bind GTP or GDP. Moreover, the G dimerization partners of these sporulation-specific septins appear to carry compensatory changes in residues that form contacts at the G interface to help retain stability despite the absence of bound GDP or GTP in the facing subunit. During septin evolution in nematodes, apparent loss of GTPase activity was also accompanied by changes in predicted G interface contacts. Overall, our observations support the conclusion that the primary function of nucleotide binding and hydrolysis by septins is to ensure formation of G interfaces that impose the proper subunit-subunit order within the hetero-oligomer. [ABSTRACT FROM AUTHOR]

Sex steroids are known to modulate immune responses and as a result many of the immune parameters in seasonally breeding organisms show reproductive‐phase dependent variation. Androgens, the male sex steroids, are largely reported to be immunosuppressive. Together with other pattern recognition receptors, the nucleotide‐binding and oligomerization domain‐like receptors (NLRs) serve as intracellular sentinels and are essential to defense mechanisms. Interestingly, to date the transcriptional modulation of NLRs by androgens has not been explored. In the present study, we investigated the reproductive‐phase dependent expression of NLRs in the male spotted snakehead Channa punctata. Furthermore, the effect of dihydrotestosterone (DHT) on NLR expression was studied. The expression of NLRs was observed to be most pronounced during the spawning phase of the fish, which is marked by the highest testosterone level. In vivo as well as in vitro studies showed the diverse effect of DHT on NLR expression depending on the duration and mode of treatment, as well as the immune tissue studied. [ABSTRACT FROM AUTHOR]

The three-dimensional structure of recombinant nicking endonuclease S11C Cys-free Nt.BspD6I was determined at 1.85 Å resolution. Nickase S11C Cys-free Nt.BspD6I was produced by the reversion back to Cys11 in Cys-free Nt.BspD6I using site-directed mutagenesis. An analysis of the crystal structure of nickase S11C Cys-free Nt.BspD6I demonstrated that the reversion back to Cys11 induces significant conformational changes in the recognition domain of nickase, which are accompanied by changes in its functions, such as a decrease in the affinity to DNA, the loss of the ability to undergo oligomerization, and high activity of restriction endonuclease S11C Cys-free R.BspD6I. [ABSTRACT FROM AUTHOR]

Cryo-electron microscopy (cryo-EM) analyses of the inner kinetochore complex constitutive centromere-associated network (CCAN) bound to the centromere protein (CENP)-A nucleosome updated our understanding of kinetochore organization. CCAN subunit molecular interactions and centromere localization modes are modulated during cell cycle progression, suggesting dynamic kinetochore structure. Chicken Knl2 possesses a CENP-C-like motif that binds to the CENP-A nucleosome in interphase cells, suggesting that, in addition to its role in new CENP-A deposition, chicken Knl2 stabilizes the CENP-A nucleosome, similar to human CENP-C. The kinetochore functions as a higher-order assembly on regional centromeres. CCAN clustering via CENP-C and Ndc80 clustering in its loop region are important kinetochore features required for robust binding to spindle microtubules. The kinetochore is a supramolecular complex that facilitates faithful chromosome segregation by bridging the centromere and spindle microtubules. Recent functional and structural studies on the inner kinetochore subcomplex, constitutive centromere-associated network (CCAN) have updated our understanding of kinetochore architecture. While the CCAN core establishes a stable interface with centromeric chromatin, CCAN organization is dynamically altered and coupled with cell cycle progression. Furthermore, the CCAN components, centromere protein (CENP)-C and CENP-T, mediate higher-order assembly of multiple kinetochore units on the regional centromeres of vertebrates. This review highlights new insights into kinetochore rigidity, plasticity, and clustering, which are key to understanding temporal and spatial regulatory mechanisms of chromosome segregation. [ABSTRACT FROM AUTHOR]

Salicylaldehyde imine nickel complexes Ni1‐Ni10 containing different electron‐donating and electron‐withdrawing groups on benzene rings were synthesized, using ethylenediamine, salicylaldehyde derivatives with different substituents and nickel chloride hexahydrate as raw materials. Structure characterization, such as elemental analysis, Fourier transform infrared (FT‐IR), nuclear magnetic resonance (NMR), ultraviolet–visible (UV–Vis), and electrospray ionization mass spectrometry (ESI‐MS), confirmed that the structure of synthesized complexes was consistent with the theoretical. Salicylaldehyde imine nickel complexes exhibited good catalytic activity in ethylene oligomerization process, and complexes containing electron‐donating groups on the benzene ring had higher catalytic activity than complexes containing electron‐withdrawing groups on the benzene ring. With the increase of steric hindrance of phenol hydroxyl ortho‐substituents, the catalytic activity decreased, as well as the catalytic selectivity toward olefins with higher carbon number. The relationship between structure and catalytic properties was further studied by density functional theory (DFT) calculations, and the possible mechanism of nickel complexes catalyzing ethylene oligomerization was proposed. [ABSTRACT FROM AUTHOR]

Two aliphatic diamine-bridged ferrocene ligands (C2-Fe-Ligand and C6-Fe-Ligand) were synthesized with aliphatic diamine and formylferrocene, and the corresponding bimetallic active site complexes (Ni-C2-Fe, Co-C2-Fe, and Ni-C6-Fe) were prepared to catalyze ethylene oligomerization. The ligands and the corresponding complexes were characterized by FTIR, 1H NMR, TG, ESI-MS, XRD, and SEM. The SEM results of the ligands confirmed that the length of the bridged group had an influence on the morphology, and an increase in the carbon length led to irregular short rods to the irregular flakes with a large size. The bimetallic complexes catalyzed efficiently ethylene oligomerization with MAO as co-catalyst, and these complexes produced C4 and C6 olefins. Ni-C2-Fe showed higher activity of 6.31 × 104 g·(mol Ni·h)−1 in cyclohexane at Al/Ni molar ratio of 700, temperature of 25 °C, and pressure of 0.5 MPa. Compared with single active site catalysts, the bimetallic active site catalysts had a higher selectivity for C4 olefin because of the competitive insertion of ethylene between different active centers. The modification of the metal center tuned the catalytic performance of the complexes in ethylene oligomerization. [ABSTRACT FROM AUTHOR]