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This paper contributes to the clarification of the concept of 'typicality' discussed in contemporary philosophy of physics by conceiving the nomological status of a typical behaviour such as that expressed in the Second Law of Thermodynamics as a 'minutis rectis law'. A brief sketch of the discovery of 'typicality' shows that there were ideas of typical behaviour not only in physics but also in sociology. On this basis and in analogy to the Second Law of Thermodynamics, it is shown that the nomological status of sociological laws such as Gresham's Law can also be conceived as 'minutis rectis laws'., Author(s): Gerhard Wagner [sup.1] Author Affiliations: (1) grid.7839.5, 0000 0004 1936 9721, Institut für Soziologie, Goethe Universität, , Theodor W. Adorno Platz 6, 60623, Frankfurt am Main, Germany Introduction In [...]

BACKGROUND. Neurofibroma/schwannoma hybrid nerve sheath tumors (N/S HNSTs) are neoplasms associated with larger nerves that occur sporadically and in the context of schwannomatosis or neurofibromatosis type 2 or 1. Clinical management of N/S HNSTs is challenging, especially for large tumors, and established systemic treatments are lacking. METHODS. We used next-generation sequencing and array-based DNA methylation profiling to determine the clinically actionable genomic and epigenomic landscapes of N/S HNSTs. RESULTS. Whole-exome sequencing within a precision oncology program identified an activating mutation (p.Asp769Tyr) in the catalytic domain of the ERBB2 receptor tyrosine kinase in a patient with schwannomatosis-associated N/S HNST, and targeted treatment with the small-molecule ERBB inhibitor lapatinib led to prolonged clinical benefit and a lasting radiographic and metabolic response. Analysis of a multicenter validation cohort revealed recurrent ERBB2 mutations (p.Leu755Ser, p.Asp769Tyr, p.Val777Leu) in N/S HNSTs occurring in patients who met diagnostic criteria for sporadic schwannomatosis (3 of 7 patients), but not in N/S HNSTs arising in the context of neurofibromatosis (6 patients) or outside a tumor syndrome (1 patient), and showed that ERBB2-mutant N/S HNSTs cluster in a distinct subgroup of peripheral nerve sheath tumors based on genome-wide DNA methylation patterns. CONCLUSION. These findings uncover a key biological feature of N/S HNSTs that may have important diagnostic and therapeutic implications. FUNDING. This work was supported by grant H021 from DKFZ-HIPO, the University Cancer Center Frankfurt, and the Frankfurt Research Funding Clinician Scientist Program., Introduction Neurofibroma/schwannoma hybrid nerve sheath tumors (N/S HNSTs) are peripheral nerve sheath tumors that are recognized as a distinct entity by the 2016 update of the World Health Organization (WHO) [...]

Eukaryotic transcription activators stimulate the expression of specific sets of target genes through recruitment of co-activators such as the RNA polymerase II-interacting Mediator complex (1,2). Aberrant function of transcription activators has been implicated in several diseases. However, therapeutic targeting efforts have been hampered by a lack of detailed molecular knowledge of the mechanisms of gene activation by disease-associated transcription activators. We previously identified an activator-targeted three-helix bundle KIX domain in the human MED15 Mediator subunit that is structurally conserved in Gal11/Med15 Mediator subunits in fungi (3,4). The Gal11/Med15 KIX domain engages pleiotropic drug resistance transcription factor (Pdr1) orthologues, which are key regulators of the multidrug resistance pathway in Saccharomyces cerevisiae and in the clinically important human pathogen Candida glabrata (5,6). The prevalence of C. glabrata is rising, partly owing to its low intrinsic susceptibility to azoles, the most widely used antifungal agent (7,8). Drug-resistant clinical isolates of C. glabrata most commonly contain point mutations in Pdr1 that render it constitutively active (9-14), suggesting that this transcriptional activation pathway represents a linchpin in C. glabrata multidrug resistance. Here we perform sequential biochemical and in vivo high-throughput screens to identify small-molecule inhibitors of the interaction of the C. glabrata Pdr1 activation domain with the C. glabrata Gal11A KIX domain. The lead compound (iKIX1) inhibits Pdr1-dependent gene activation and re-sensitizes drug-resistant C. glabrata to azole antifungals in vitro and in animal models for disseminated and urinary tract C. glabrata infection. Determining the NMR structure of the C. glabrata Gal11A KIX domain provides a detailed understanding of the molecular mechanism of Pdr1 gene activation and multidrug resistance inhibition by iKIX1. We have demonstrated the feasibility of small-molecule targeting of a transcription factor-binding site in Mediator as a novel therapeutic strategy in fungal infectious disease., On the basis of our previous findings that deletion of the KIX domain of S. cerevisiae GAL11 or C. glabrata GAL11A abrogates Pdrl-dependent transcriptional responses and xenobiotic tolerance we hypothesized [...]

In dealing with the problem of personal injury, societies have to make a choice between regimes of tort liability, the general social security system, and tailor-made no-fault compensation schemes. The [...]

IV. REAL-WORLD CHOICES BETWEEN WORKERS' COMPENSATION AND EMPLOYERS' LIABILITY A. The Motives for the Revival of Employers' Liability 1. Getting Rid of the 'Industrial Preference' The economic analysis of workers' [...]

The PI3-kinase (PI3K) pathway regulates many cellular processes, especially cell metabolism, cell survival, and apoptosis. Phosphatidylinositol-3,4,5-trisphosphate (PIP3), the product of PI3K activity and a key signaling molecule, acts by recruiting pleckstrin-homology (PH) domain-containing proteins to cell membranes. Here, we describe a new structural class of nonphosphoinositide small molecule antagonists (PITenins, PITs) of PIP3-PH domain interactions ([IC.sub.50] ranges from 13.4 to 31 [micro]M in PIP3/Akt PH domain binding assay). PITs inhibit interactions of a number of PIP3-binding PH domains, including those of Akt and PDK1, without affecting several PIP2-selective PH domains. As a result, PITs suppress the PI3K-PDK1-Akt pathway and trigger metabolic stress and apoptosis. A PIT-1 analog displayed significant antitumor activity in vivo, including inhibition of tumor growth and induction of apoptosis. Overall, our studies demonstrate the feasibility of developing specific small molecule antagonists of PIP3 signaling. PIP3 antagonist | anticancer doi/ 10.1073/pnas.1004522107

Proliferating cells, including cancer ceils, require altered metabolism to efficiently incorporate nutrients such as glucose into biomass. The M2 isoform of pyruvate kinase (PKM2) promotes the metabolism of glucose by aerobic glycolysis and contributes to anabolic metabolism. Paradoxically, decreased pyruvate kinase enzyme activity accompanies the expression of PKM2 in rapidly dividing cancer ceils and tissues. We demonstrate that phosphoenolpyruvate (PEP), the substrate for pyruvate kinase in cells, can act as a phosphate donor in mammalian cells because PEP participates in the phosphorylation of the glycolytic enzyme phosphoglycerate mutase (PGAM1) in PKM2-expressing ceils. We used mass spectrometry to show that the phosphate from PEP is transferred to the catalytic histidine ([His.sup.11]) on human PGAM1. This reaction occurred at physiological concentrations of PEP and produced pyruvate in the absence of PKM2 activity. The presence of histidine-phosphorylated PGAM1 correlated with the expression of PKM2 in cancer cell lines and tumor tissues. Thus, decreased pyruvate kinase activity in PKM2-expressing cells allows PEP-dependent histidine phosphorylation of PGAM1 and may provide an alternate glycolytic pathway that decouples adenosine triphosphate production from PEP-mediated phosphotransfer, allowing for the high rate of glycolysis to support the anabolic metabolism observed in many proliferating cells. 10.1126/science.1188015

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.tibs.2010.03.005 Byline: Sebastian Hiller (1), Jeff Abramson (2), Carmen Mannella (3), Gerhard Wagner (1), Kornelius Zeth (4) Abstract: The most abundant protein of the mitochondrial outer membrane is the voltage-dependent anion channel (VDAC), which facilitates the exchange of ions and molecules between mitochondria and cytosol and is regulated by interactions with other proteins and small molecules. VDAC has been studied extensively for more than three decades, and last year three independent investigations revealed a structure of VDAC-1 exhibiting 19 transmembrane [beta]-strands, constituting a unique structural class of [beta]-barrel membrane proteins. Here, we provide a historical perspective on VDAC research and give an overview of the experimental design used to obtain these structures. Furthermore, we validate the protein refolding approach and summarize the biochemical and biophysical evidence that links the 19-stranded structure to the native form of VDAC. Author Affiliation: (1) Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave., Boston, MA 02115, USA (2) Department of Physiology, University of California, Los Angeles, CA 90095, USA (3) Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12201, USA (4) Max Planck Institute of Developmental Biology, Department Protein Evolution, Spemannstr. 35, 72076 Tubingen, Germany

A vaccine capable of stimulating protective antiviral antibody responses is needed to curtail the global AIDS epidemic caused by HIV-1. Although rarely elicited during the course of natural infection or upon conventional vaccination, the membrane-proximal ectodomain region (MPER) of the HIV-1 glycoprotein of [M.sub.r] 41,000 (gp41) envelope protein subunit is the target of 3 such human broadly neutralizing antibodies (BNAbs): 4E10, 2F5, and Z13e1. How these BNAbs bind to their lipid-embedded epitopes and mediate antiviral activity is unclear, but such information might offer important insight into a worldwide health imperative. Here, EPR and NMR techniques were used to define the manner in which these BNAbs differentially recognize viral membrane-encrypted residues configured within the L-shaped helix--hinge--helix MPER segment. Two distinct modes of antibody-mediated interference of viral infection were identified. 2F5, like 4E10, induces large conformational changes in the MPER relative to the membrane. However, although 4E10 straddles the hinge and extracts residues W672 and F673, 2F5 lifts up residues N-terminal to the hinge region, exposing L669 and W670. In contrast, Z13e1 effects little change in membrane orientation or conformation, but rather immobilizes the MPER hinge through extensive rigidifying surface contacts. Thus, BNAbs disrupt HIV-1 MPER fusogenic functions critical for virus entry into human CD4 T cells and macrophages either by preventing hinge motion or by perturbing MPER orientation. HIV-1 MPER features important for targeted vaccine design have been revealed, the implications of which extend to BNAb targets on other viral fusion proteins. membrane-proximal ectodomain region | neutralizing antibody | vaccine design | AIDS | fusion

Non-ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) produce numerous secondary metabolites with various therapeutic/antibiotic properties (1). Like fatty acid synthases (FAS), these enzymes are organized in modular assembly lines [...]

Non-ribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) found in bacteria, fungi and plants use two different types of thioesterases for the production of highly active biological compounds (1,2). Type [...]

Multidrug resistance (MDR) is a serious complication during treatment of opportunistic fungal infections that frequently afflict immunocompromised individuals, such as transplant recipients and cancer patients undergoing cytotoxic chemotherapy. Improved knowledge [...]

Programmed Cell Death 4 (PDCD4) is a protein known to bind eukaryotic initiation factor 4A (elF4A), inhibit translation initiation, and act as a tumor suppressor. PDCD4 contains two C-terminal MA3 domains, which are thought to be responsible for its inhibitory function. Here, we analyze the structures and inhibitory functions of these two PDCD4 MA3 domains by x-ray crystallography, NMR, and surface plasmon resonance. We show that both MA3 domains are structurally and functionally very similar and bind specifically to the elF4A N-terminal domain (elF4A-NTD) using similar binding interfaces. We found that the PDCD4 MA3 domains compete with the elF4G MA3 domain and RNA for elF4A binding. Our data provide evidence that PDCD4 inhibits translation initiation by displacing elF4G and RNA from elF4A. The PDCD4 MA3 domains act synergistically to form a tighter and more stable complex with elF4A, which explains the need for two tandem MA3 domains. apoptosis | elF4G | protein | NMR | x-ray crystallography

ssDNA-binding proteins are key components of the machinery that mediates replication, recombination, and repair. Prokaryotic ssDNA-binding proteins share a conserved DNA-binding fold and an acidic C-terminal tail. It has been proposed that in the absence 1 of ssDNA, the C-terminal tail contacts the ssDNA-binding cleft, therefore predicting that the binding of ssDNA and the C-terminal--tail is mutually exclusive. Using chemical cross-linking, competition studies, and NMR chemical-shift mapping, we demonstrate that: (i) the C-terminal peptide of the gene 2.5 protein cross-links to the core of the protein only in the absence of ssDNA, (ii) the cross-linked species fails to bind to ssDNA, and (iii) a C-terminal peptide and ssDNA bind to the same overall surface of the protein. We propose that the protection of the DNA-binding cleft by the electrostatic shield of the C-terminal tail observed in prokaryotic ssDNA-binding proteins, ribosomal proteins, and high-mobility group proteins is an evolutionarily conserved mechanism. This mechanism prevents random binding of charged molecules to the nucleic acid-binding pocket and coordinates nucleic acid-protein and protein-protein interactions. gene 2.5 protein | replication

A comprehensive assessment of metabolite levels from extracts of leukocytes are obtained by recording ultrahigh-resolution [super 1]H-[super 13]C HSQC NMR spectra of cell extracts displaying spectral signatures of numerous small molecules. The results have shown that the measurement time was dramatically reduced without loss of spectral quality when nonlinear sampling (NLS) and a new high-fidelity forward maximum-entropy (FM) reconstruction algorithm was used.

Assembly of the HIV and other retroviruses is primarily driven by the oligomerization of the Gag polyprotein, the major viral structural protein capable of forming virus-like particles even in the absence of all other virally encoded components. Several critical determinants of Gag oligomerization are located in the C-terminal domain of the capsid protein (CA-CTD), which encompasses the most conserved segment in the highly variable Gag protein called the major homology region (MHR). The CA-CTD is thought to function as a dimerization module, although the existing model of CA-CTD dimerization does not readily explain why the conserved residues of the MHR are essential for retroviral assembly. Here we describe an x-ray structure of a distinct domain-swapped variant of the HIV-1 CA-CTD dimer stabilized by a single amino acid deletion. In the domain-swapped structure, the MHR-containing segment forms a major part of the dimerization interface, providing a structural mechanism for the enigmatic function of the MHR in HIV assembly. Our observations suggest that swapping of the MHR segments of adjacent Gag molecules may be a critical intermediate in retroviral assembly. Gag | major homology region | viral assembly

A study was conducted to clarify the biological role for the interaction between Bcl-[X.sub.L] and voltage-dependent anion channel (VDAC). The results suggest that Bcl-[X.sub.L] could bind to one or two VDAC molecules forming heterodimers and heterotrimers.

We introduce a eukaryotic cellular system, the Xenopus laevis oocyte, for in-cell NMR analyses of biomolecules at high resolution and delineate the experimental reference conditions for successful implementations of in vivo NMR measurements in this cell type. This approach enables quantitative NMR experiments at defined intracellular concentrations of exogenous proteins, which is exemplified by the description of in-cell NMR properties of the protein G B1 domain (GB1). Additional experiments in Xenopus egg extracts and artificially crowded in vitro solutions suggest that for this biologically inert protein domain, intracellular viscosity and macromolecular crowding dictate its in vivo behavior. These contributions appear particularly pronounced for protein regions with high degrees of internal mobility in the pure state. We also evaluate the experimental limitations of this method and discuss potential applications toward the in situ structural characterization of eukaryotic cellular activities. in-cell | high-resolution | liquid-state

Chad Ross. Naked Germany: Health, Race and the Nation. Oxford: Berg, 2005. xi + 239 pp. $ 79.95 If you ask contemporary German supporters of nudism why they practice this [...]

Eukaryotic translation initiation factor (elF) 5 is crucial for the assembly of the eukaryotic preinitiation complex. This activity is mediated by the ability of its C-terminal HEAT domain to interact with elF1, elF2, and elF3 in the multifactor complex and with elF4G in the 48S complex. However, the binding sites for these factors on elF5--C-terminal domain (CTD) have not been known. Here we present a homology model for elF5-CTD based on the HEAT domain of elF2B[epsilon]. We show that the binding site for elF2[beta] is located in a surface area containing aromatic and acidic residues (aromatic/ acidic boxes), that the binding sites for elF1 and elF3c are located in a conserved surface region of basic residues, and that elF4G binds elF5-CTD at an interface overlapping with the acidic area. Mutations in these distinct elF5 surface areas impair GCN4 translational control by disrupting preinitiation complex interactions. These results indicate that the elF5 HEAT domain is a critical nucleation core for preinitiation complex assembly and function. general amino acid control | ribosome preinitiation complex | translation initiation | translational control

The eukaryotic translation initiation factors 4A (eIF4A) and 4G (eIF4G) are crucial for the assembly of the translationally active ribosome. Even though both eIF4A domains play a role in binding the middle domain of eIF4G, the main interaction surface is located on the C-terminal domain.

Equilibrium binding experiments are widely used for the accurate characterization of binding and competitive binding behavior in biological systems. Exact analytical expressions for general competitive binding models are derived, which can also explain a commonly encountered phenomenon in these types of experiments, anticooperative incomplete displacement.

The direct protein-protein interaction between the phosphatase calcineurin and transcription factor NFAT plays important roles in a number of crucial mammalian cells signaling and regulatory events, such as activation of T cells and developmental genetic programs. The identification of small organic molecules for the targeted disruption of the NFAT-calcineurin interaction in vitro is reported.

Invariant CD3 subunit dimers (CD3[epsilon][gamma] CD3[epsilon][delta], and CD3[zeta][zeta]) are the signaling components of the [alpha][beta] T cell receptor (TCR). The recently solved structure of murine CD3[epsilon][gamma] revealed a unique side-to-side interface and central [beta]-sheets conjoined between the two C2-set Ig-like ectodomains, with the pairing of the parallel G strands implying a potential concerted piston-type movement for signal transduction. Although CD3[gamma], and CD3[delta] each dimerize with CD3[epsilon], there are differential CD3 subunit requirements for receptor assembly and signaling among T lineage subpopulations, presumably mandated by structural differences. Here we present the solution structure of the heterodimeric CD3[epsilon][delta] complex. Whereas the CD3[epsilon] subunit conformation is virtually identical to that in CD3[epsilon][gamma], the CD3[delta] ectodomain adopts a C1-set Ig fold, with a narrower GFC front face [beta]-sheet that is more parallel to the ABED back face than those [beta]-sheets in CD3[epsilon] and CD3[gamma] The dimer interface between CD3[delta] and CD3[epsilon] is highly conserved among species and of similar character to that in CD3[epsilon][gamma]. Glycosylation sites in CD3[delta] are arranged such that the glycans may point away from the membrane, consistent with a model of TCR assembly that allows the CD3[delta] chain to be in close contact with the TCR [alpha]-chain. This and many other structural and biological features provide a basis for modeling putative TCR/CD3 extracellular domain associations. The fact that the two clusters of transmembrane helices, namely, the three CD3[epsilon]-CD3[gamma]-TCR[beta] segments and the five CD3[epsilon]-CD3[delta]-TCR[alpha]-CD3[zeta]-CD3[zeta] segments, are presumably centered beneath the G strand-paired CD3 heterodimers has important implications for TCR signaling. single-chain C1-Ig fold | immunoreceptor tyrosine-based activation motif | NMR structure | T cell development

The solution structure of the reduced 27.6 kDa FAD- and NADH-binding domains (MMOR-FAD) of the reductase from 'Methylococcus capsulatus' is described. Choosing to investigate the structure of the fully reduced protein because of its greater stability and the better comparability with the MMOR-Fd domain, this was solved previously in the reduced state.

BCL-2 family proteins constitute a critical control point for the regulation of apoptosis. Protein interaction between BCL-2 members is a prominent mechanism of control and is mediated through the amphipathic α-helical BH3 segment, an essential death domain. We used a chemical strategy, termed hydrocarbon stapling, to generate BH3 peptides with improved pharmacologic properties. The stapled peptides, called 'stabilized alpha-helix of BCL-2 domains' (SAHBs), proved to be helical, protease-resistant, and cell-permeable molecules that bound with increased affinity to multidomain BCL-2 member pockets. A SAHB of the BH3 domain from the BID protein specifically activated the apoptotic pathway to kill leukemia cells. In addition, SAHB effectively inhibited the growth of human leukemia xenografts in vivo. Hydrocarbon stapling of native peptides may provide a useful strategy for experimental and therapeutic modulation of protein-protein interactions in many signaling pathways., BCL-2 is the founding member of a protein family (1-3) composed of pro- and anti-apoptotic molecules that serve as an essential control point in apoptosis, governing susceptibility to cell death [...]

Transient or reversible protein--protein interactions are commonly used to ensure efficient targeting of signaling enzymes to their cellular substrates. These interactions include direct binding to substrate, interaction with an accessory or scaffold protein, and positioning at subcellular locations in proximity to substrates. The existence of specialized targeting mechanisms raises the possibility of designing inhibitors that do not block enzyme activity per se, but rather interfere with targeting of the enzyme to one or more of its substrates within the cell. Here, we identify small organic molecules that specifically block targeting of the protein phosphatase calcineurin to its substrate nuclear factor of activated T cells (NFAT, also termed NFATc) and show that they are effective inhibitors of calcineurin-NFAT signaling.

The T cell coreceptors CD4 and CD8 both associate via their cytoplasmic tails with the N-terminus of the Src-family tyrosine kinase Lck. These interactions require zinc and are critical for T cell development and activation. We examined the folding and solution structures of ternary CD4-Lck-[Zn.sup.2+] and CD8α-Lck-[Zn.sup.2+] complexes. The coreceptor tails and the Lck N-terminus are unstructured in isolation but assemble in the presence of zinc to form compactly folded heterodimeric domains. The cofolded complexes have similar 'zinc clasp' cores that are augmented by distinct structural elements. A dileucine motif required for clathrin-mediated endocytosis of CD4 is masked by Lck., The Src-family tyrosine kinase Lck transduces signals that are required for normal T lymphocyte development and for antigen-dependent activation of mature T cells. Lck associates non-covalently via its N-terminal region [...]

The translation initiation factors (IFs) IF1/eIF1A and IF2/eIF5B have been conserved throughout all kingdoms. Although the central roles of the bacterial factors IF1 and IF2 were established long ago, the importance of their eukaryotic homologs, eukaryotic IFs (eIFs) eIF1A and eIF5B, has only recently become evident. The translation machinery in eukaryotes is more complex and accordingly, eIF1A and eIF5B seem to have acquired a number of new functions while also retaining many of the roles of bacterial IF1 and IF2. IF1 and IF2 have been shown to interact on the ribosome but no binding has been detected for the free factors. In contrast, yeast eIF1A and eIF5B have been reported to interact in the absence of ribosomes. Here, we have identified the binding interface between human eIF1A and the C-terminal domain of eIF5B by using solution NMR. That interaction interface involves the C termini of the two proteins, which are not present in bacterial IF1 and IF2. The interaction is, therefore, unique to eukaryotes. A structural model for the interaction of eIF1A and eIF5B in the context of the ribosome is presented. We propose that eIF1A and eIF5B simultaneously interact at two sites that are >50 [Angstrom] apart: through their C termini as reported here, and through an interface previously identified in bacterial IF1 and IF2. The binding between the C termini of eIF1A and eIF5B has implications for eukaryote-specific mechanisms of recruitment and release of translation IFs from the ribosome.

Adaptation to hypoxia is mediated by transactivation of hypoxiaresponsive genes by hypoxia-inducible factor-1 (HIF-1) in complex with the CBP and p300 transcriptional coactivators. We report the solution structure of the cysteine/histidine-rich 1 (CH1) domain of p300 bound to the C-terminal transactivation domain of HIF-1[alpha]. CH1 has a triangular geometry composed of four a-helices with three intervening [Zn.sup.2+]-coordinating centers. CH1 serves as a scaffold for folding of the HIF-1[alpha] C-terminal transactivation domain, which forms a vise-like clamp on the CH1 domain that is stabilized by extensive hydrophobic and polar interactions. The structure reveals the mechanism of specific recognition of p300 by HIF-1[alpha], and shows how HIF-1[alpha] transactivation is regulated by asparagine hydroxylation.

Research has been conducted on the 26S proteasome, important for the protein proteolysis. The interactions of the 19S complex's S5a component with various ubiquitin-like modules have been investigated in examining the way the polyubiquitinated proteins are targeted to the proteasome and the results are described.

Research has been conducted on the soluble methane monooxygenase from Methylococcus capsulatus. The solution structure of the reduced from the amino acid ferredoxin domain has been determined via the nuclear magnetic resonance spectroscopy and restrained molecular dynamics calculations and the results are reported.

Solution structure of a heterodimeric CD3epsilongamma ectodomain complex, an integral component of the T cell receptor (TCR) and pre-TCR, reveals that TCR-based signal transduction is facilitated by an hydrophobic interphase between the two C2-set immunoglobulin-like domains and parallel pairing of the C-terminal beta-strands of the complex.

The binding of GAL4 to GAL11P in Saccharomyces cerevisiae is a unique structural motif for an activating region able to bind to one target to cause gene expression, although the binding is an artificial interaction. GAL4-dd is made up of three helical segments connected by flexible loops. Dimerization is via coiled-coil interactions of the three helices. Nuclear magnetic resonance titration was used to study interaction of the GAL4-dd with GAL11P(sub.261-352). GAL11P is a part of the RNA-polymerase II holoenzyme.

Research demonstrates that the N-terminal domain of Escherichia coli Ada protein maintains zinc-thiolate center upon methylation. The methylated -Ada/DNA complexes make contacts with N-terminal Ada but not with DNA. Data indicate that methylation affects DNA binding and transcriptional activation.

Author(s): Raimund Muscheler (corresponding author) [1]; Jürg Beer [1]; Gerhard Wagner [1]; Robert C. Finkel [2] Variations in atmospheric radiocarbon ([sup.14] C) concentrations can be attributed either to changes in [...]

Research has been conducted on the (super)15 N heteronuclear single quantum coherence resonance. The paramagnetic broadening of the resonance by means od a large perdeuterated protein is discussed.

Research is presented describing the production of short RNA, incorporating the m7GpppA cap structure, by combining enzymatic synthesis with chemical synthesis. Three capped RNA molecules are synthesized.

Results describe the structure of CIDE-N of human CIDE-B protein and show its interaction with CIDE-N domains of both 40 kDA capsule-activated DNA fragmentation factor (DFF40) and the inhibitor DFF45. Role of this novel bipolar interaction in the regulation of downstream events of apoptosis is discussed.

The soluble methane monooxygenase (sMMO; EC 1.14.13.25) from the pseudothermophile Methylococcus capsulatus (Bath) is a three-component enzyme system that catalyzes the selective oxidation of methane to methanol. We have used NMR spectroscopy to produce a highly refined structure of MMOB, the 16-kDa regulatory protein of this system. This structure has a unique and intricate fold containing seven [Beta]-strands forming two [Beta]-sheets oriented perpendicular to each other and bridged by three [Alpha]-helices. The rate and efficiency of the methane hydroxylation by sMMO depend on dynamic binding interactions of the hydroxylase with the reductase and regulatory protein components during catalysis. We have monitored by NMR the binding of MMOB to the hydroxylase in the presence and absence of the reductase. The results of these studies provide structural insight into how the regulatory protein interacts with the hydroxylase.

The solution structure of tGCN5 catalytic domain in complex with coenzyme A has been determined. The structure consists of the amino-terminal domain similar to those of other GCN5-related N-acetyltransferases, and the carboxy-terminal domain. Coenzyme A binds between the two domains, and chemical shift changes on titration with histone H3 peptides suggest a binding site at the domain boundary opposite coenzyme A.

An intracellular protein termed CD2 binding protein 2 (CD2BP2), which binds to a site containing two PPPGHR segments within the cytoplasmic region of CD2, was identified. Mutagenesis and NMR analysis demonstrated that the CD2 binding region of CD2BP2 includes a 17-aa motif (GPY[orF]xxxxM[orV]xxWxxx GYF), also found in several yeast and Caenorhabditis elegans proteins of unknown function. In Jurkat T cells, over-expression of the isolated CD2BP2 domain binding to CD2 enhances the production of interleukin 2 on crosslinking of CD2 but not the T cell receptor. Hence, a proline-binding module distinct from SH3 and WW domains regulates protein-protein interactions.

The spontaneous folding ability of many polypeptides contradicts the observation of Levinthal that unfolded polypeptides are unable to fold in a reasonable time. The folding kinetics of villin 14T have been studied under a range of experimental conditions. Its solution structure shows a distinctive fold comprising a five stranded central beta-sheet, flanked by two alpha-helices.

A study was conducted to characterize the three-dimensional caspase recruitment domain structure of RAIDD adaptor proteins using nuclear magnetic resonance (NMR) spectroscopy. Varian spectrometers were used to determine NMR spectra while structure computations were carried out based on simulated annealing protocols. Results indicated that the adaptor proteins support a six-helix bundle and distinct charged surface patches.

Protein kinase such as the casein kinase Ialpha and MEKK1 have synergic roles in suppressing NF-AT. MEKK1 protein kinase indirectly suppresses NF-AT4 nuclear import while casein kinase Ialpha directly binds and phosphorylates the transcription factor NF-AT4 which resulted to the inhibition of the transcription factor's nuclear translocation. These transcriptional factors have important function in maintaining and enhancing the masking activity responsible in controlling NF-AT4.