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Dipeptide production from extracellular proteins is crucial for Porphyromonas gingivalis, a pathogen related to chronic periodontitis, because its energy production is entirely dependent on the metabolism of amino acids predominantly incorporated as dipeptides. These dipeptides are produced by periplasmic dipeptidyl-peptidase (DPP)4, DPP5, DPP7, and DPP11. Although the substrate specificities of these four DPPs cover most amino acids at the penultimate position from the N terminus (P1), no DPP is known to cleave penultimate Gly, Ser, Thr, or His. Here, we report an expanded substrate preference of bacterial DPP7 that covers those residues. MALDI-TOF mass spectrometry analysis demonstrated that DPP7 efficiently degraded incretins and other gastrointestinal peptides, which were successively cleaved at every second residue, including Ala, Gly, Ser, and Gln, as well as authentic hydrophobic residues. Intravenous injection of DPP7 into mice orally administered glucose caused declines in plasma glucagon-like peptide-1 and insulin, accompanied by increased blood glucose levels. A newly developed coupled enzyme reaction system that uses synthetic fluorogenic peptides revealed that the P1′ and P2′ residues of substrates significantly elevated kcat values, providing an expanded substrate preference. This activity enhancement was most effective toward the substrates with nonfavorable but nonrepulsive P1 residues in DPP7. Enhancement of kcat by prime-side residues was also observed in DPP11 but not DPP4 and DPP5. Based on this expanded substrate specificity, we demonstrate that a combination of DPPs enables proteolytic liberation of all types of N-terminal dipeptides and ensures P. gingivalis growth and pathogenicity., Journal of Biological Chemistry, 298(3), art. no. 101585; 2022

Acylpeptidyl-oligopeptidase (AOP), which has been recently identified as a novel enzyme in a periodontopathic bacterium, Porphyromonas gingivalis, removes di- and tri-peptides from N-terminally acylated polypeptides, with a preference for hydrophobic P1-position amino acid residues. To validate enzymatic properties of AOP, characteristics of two bacterial orthologues from Bacteroides dorei (BdAOP), a Gramnegative intestinal rod, and Lysinibacillus sphaericus (LsAOP), a Gram-positive soil rod, were determined. Like P. gingivalis AOP (PgAOP), two orthologues more efficiently hydrolyzed N-terminal acylated peptidyl substrates than non-acylated ones. Optimal pH was shifted from 7.0 ? 8.9 for N-acylated to 8.5 ? 9.5 for non-acylated substrates, indicating preference for non-charged hydrophobic N-terminal residues. Hydrophobic P1- and P2-position preferences were common in the three AOPs, although PgAOP preferred Leu and the others preferred Phe at the P1 position. In vitro mutagenesis demonstrated that Phe647 in PgAOP was responsible for the P1 Leu preference. In addition, bacterial AOPs commonly liberated acetyl-Ser1-Tyr2 from amelanocyte- stimulating hormone. Taken together, although these three bacterial AOPs exhibited some variations in biochemical properties, the present study demonstrated the existence of a group of exopeptidases that preferentially liberates mainly dipeptides from N-terminally acylated polypeptides with a preference for hydrophobic P1 and P2- position residues., Biochimie, 163, pp.50-27; 2019

This paper presents a new methodology for providing insight into manufacturing using key performance indicators (KPIs: ISO 22400), and to achieve a Smart Manufacturing (SM) using a simple indicator. This indicator is very easy to understand for factory owner, production manager and installation staff, and so on. It is Smart Manufacturing Kaizen Level (SMKL). Industry 4.0 (I4.0) was announced by Germany in 2011. Also, Industrial IoT (IIoT) and SM has become a global trend now. Various consortiums related to this trend have been established in each country, such as PI 4.0 in Germany, IIC in the United States, RRI and IVI in Japan. There are very significant discussions in every consortium. As a result, various types of test beds have been evaluated and various international standards have been discussed. However, there are some issues to achieve a SM using the IIoT. First, it is difficult for factory owners to understand the Return on Investment (ROI) of the SM, and to make the decisions of continuous investment. Second, especially for Small and Medium Enterprises (SMEs), the company has few or no IIoT experts and only limited consultants who can support the IIoT. By using SMKL, factory owner will be possible to understand the ROI of the SM, and to make the decisions of continuous investment. As a result, the growth of the IIoT market, including SMEs, may be expected to accelerate in the future. In addition, SM system can be easily constructed by using the international standardization technology for industry (OPC UA (IEC 62541), FDT® (IEC 624 53), PLCopen® (IEC 61131-3), AutomationML (IEC 62714)). In this paper, we propose a use case for SMKL and created a demonstration using miniature machines and 3D simulator in IIFES2019 and proved the effectiveness of our proposal. Also, it is concluded that SMKL use case takes important role to assist the MBSE approach for SM implementation.

Bacterial dipeptidyl-peptidase (DPP) 7 liberates a dipeptide with a preference for aliphatic and aromatic penultimate residues from the N-terminus. Although synthetic substrates are useful for activity measurements, those currently used are problematic, because they are more efficiently degraded by DPP5. We here aimed to develop a potent and specific substrate and found that the kcat/Km value for Phe-Met-methylcoumaryl-7-amide (MCA) (41.40?±?0.83?μM?1?s?1) was highest compared to Met-Leu-, Leu-Leu-, and Phe-Leu-MCA (1.06?3.77?μM?1?s?1). Its hydrolyzing activity was abrogated in a Porphyromonas gingivalis dpp7-knockout strain. Conclusively, we propose Phe-Met-MCA as an ideal synthetic substrate for DPP7., Analytical Biochemistry, 548, pp.78-81; 2018

Peptidase family S46 consists of two types of dipeptidyl-peptidases (DPPs), DPP7 and DPP11, which liberate dipeptides from the N-termini of polypeptides along with the penultimate hydrophobic and acidic residues, respectively. Their specificities are primarily defined by a single amino acid residue, Gly673 in DPP7 and Arg673 in DPP11 (numbering for Porphyromonas gingivalis DPP11). Bacterial species in the phyla Proteobacteria and Bacteroidetes generally possess one gene for each, while Bacteroides species exceptionally possess three genes, one gene as DPP7 and two genes as DPP11, annotated based on the full-length similarities. In the present study, we aimed to characterize the above-mentioned Bacteroides S46 DPPs. A recombinant protein of the putative DPP11 gene BF9343_2924 from Bacteroides fragilis harboring Gly673 exhibited DPP7 activity by hydrolyzing Leu-Leu-4-methylcoumaryl-7-amide (MCA). Another gene, BF9343_2925, as well as the Bacteroides vulgatus gene (BVU_2252) with Arg673 was confirmed to encode DPP11. These results demonstrated that classification of S46 peptidase is enforceable by the S1 essential residues. Bacteroides DPP11 showed a decreased level of activity towards the substrates, especially with P1-position Glu. Findings of 3D structural modeling indicated three potential amino acid substitutions responsible for the reduction, one of which, Asn650Thr substitution, actually recovered the hydrolyzing activity of Leu-Glu-MCA. On the other hand, the gene currently annotated as DPP7 carrying Gly673 from B. fragilis (BF9343_0130) and Bacteroides ovatus (Bovatus_03382) did not hydrolyze any of the examined substrates. The existence of a phylogenic branch of these putative Bacteroides DPP7 genes classified by the C-terminal conserved region (Ser571-Leu700) strongly suggests that Bacteroides species expresses a DPP with an unknown property. In conclusion, the genus Bacteroides exceptionally expresses three S46-family members; authentic DPP7, a new subtype of DPP11 with substantially reduced specificity for Glu, and a third group of S46 family members., Biochimie, 147, pp.25-35; 2018

The authors report on anisotropic thermal transport in the spin-1/2 triangular-lattice antiferromagnet Cs${}_{2}$CuCl${}_{4}$ close to the transition into the three-dimensional long-range-ordered state. This behavior is related to an additional heat-transport channel through magnetic excitations, that can best propagate along the direction of the largest exchange interaction.

High-resolution time-of-flight powder neutron diffraction and high-field magnetization were measured to investigate the magnetic structure and existence of a field-induced magnetic phase transition in the distorted kagome antiferromagnet ${\mathrm{Cs}}_{2}{\mathrm{Cu}}_{3}{\mathrm{SnF}}_{12}$. Upon cooling from room temperature, the compound undergoes a structural phase transition at ${T}_{\mathrm{t}}=185\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ from the rhombohedral space-group $R\overline{3}m$ with the perfect kagome spin network to the monoclinic space-group $P{2}_{1}/n$ with the distorted kagome planes. The distortion results in three inequivalent exchange interactions among the $S=1/2\phantom{\rule{0.28em}{0ex}}{\mathrm{Cu}}^{2+}$ spins that magnetically order below ${T}_{\mathrm{N}}=20.2\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. Magnetization measured with a magnetic field applied within the kagome plane reveals small in-plane ferromagnetism resulting from spin canting. On the other hand, the out-of-plane magnetization does not show a clear hysteresis loop of the ferromagnetic component nor a prominent anomaly up to 170 T with the exception of the subtle kneelike bend around 90 T, which could indicate the 1/3 magnetization plateau. The combined analysis using the irreducible representations of the magnetic space groups and magnetic structure refinement on the neutron powder-diffraction data suggests that the magnetic moments order in the magnetic space-group $P{2}_{1}^{\ensuremath{'}}/{n}^{\ensuremath{'}}$ with the all-in--all-out spin structure, which by symmetry allows for the in-plane canting, consistent with the in-plane ferromagnetism observed in the magnetization.

We have conducted magnetization measurements of the $S = 1$ spin-ladder compound BIP-TENO using the single-turn coil method which generates micro-second pulsed magnetic field. We observed three magnetization plateaus in the magnetization process up to 100 T. We have also found that the magnetization process depends on the sweep speed of the magnetic fields. Possible origins of this phenomenon are (1) lowering temperature of the samples due to magnetocaloric effect with adiabatic condition realized in the fast (micro-second) pulsed magnetic field, and (2) spin-lattice separation due to a slow response of the magnetostriction whose response time is longer than microsecond range.

We carried out inelastic neutron scattering experiments on a buckled honeycomb lattice antiferromagnet Ba$_{2}$NiTeO$_{6}$ exhibiting a stripe structure at a low temperature. Magnetic excitations are observed in the energy range of $\hbar \omega \lesssim 10$ meV having an anisotropy gap of 2 meV at 2 K. We perform spin-wave calculations to identify the spin model. The obtained microscopic parameters are consistent with the location of the stripe structure in the classical phase diagram. Furthermore, the Weiss temperature independently estimated from a bulk magnetic susceptibility is consistent with the microscopic parameters. The results reveal that a competition between the NN and NNN interactions that together with a relatively large single ion magnetic anisotropy stabilize the stripe magnetic structure., Comment: 6 pages, 5 figures

This paper presents application of ISO22400 (Key Performance Indicators, KPIs) for manufacturing system. The KPIs defined in ISO 22400-1 are intended to be calculated using data from the control domain (Levels 1 and 2), and to provide both the enterprise domain and the MOM domain with decision support information to manage the enterprise. However IS022400 does not define what data should be used to compose the KPI elements. Therefore this could be lack of important information to implement KPI management systems. It could result a gap about understanding of engineers between the M0M domain and the control domain. To avoid the situation, this paper provides suggestions with examples for modelling of the KPI element described in the ISO 22400. Further this paper suggests conforming to the international standards like 0PC UA(IEC62541), FDT® (IEC62453), PLCopen® (IEC 61131-3) and AutomationML(IEC 62714) to make interoperability between systems deployed in the domains.

Porphyromonas gingivalis, a Gram-negative asaccharolytic anaerobe, is one of the major causative organisms of chronic periodontitis. The bacterium utilizes amino acids as energy and carbon sources, and incorporates them mainly as dipeptides. Therefore, a wide variety of dipeptide production processes mediated by dipeptidyl-peptidases (DPPs) should be beneficial for the organism. In the present study, we identified the fourth P. gingivalis enzyme, DPP5. A DPP7-like activity still remained in a dpp4-7-11 disrupted P. gingivalis ATCC 33277. PGN_0756, currently annotated as a prolyl oligopeptidase, possessed an activity indistinguishable from that of the triple dpp gene-disrupted strain, and was identified as a bacterial orthologue of fungal DPP5, because of its substrate specificity and 28.5% amino acid sequence identity with an Aspergillus fumigatus entity. P. gingivalis DPP5 was composed of 684 amino acids with an apparent molecular weight of 66 kDa, while it preferred Ala and hydrophobic residues, had no activity toward Pro at the P1 position, and no preference for hydrophobic P2 residues, showed an optimal pH of 6.7 in the presence of NaCl, demonstrated kcat/Km values for Gly-Phe-MCA and Lys-Ala-MCA of 13.01 and 11.02 μM-1 s-1, respectively, and was localized in the periplasm. DPP5 elaborately complemented DPP7 in liberation of dipeptides with hydrophobic P1 residues. Examinations of dpp- and gingipain gene-disrupted mutants indicated that DPP4, DPP5, DPP7, and DPP11 together with Arg- and Lys-gingipains cooperatively liberate most dipeptides from nutrient oligopeptides. This is the first study to report that DPP5 is expressed not only in eukaryotes, but also distributed in prokaryotes., Journal of Biological Chemistry, 289(9), pp.5436-5448; 2014

We successfully synthesized single crystals of the verdazyl radical $2\text{\ensuremath{-}}\mathrm{Cl}\text{\ensuremath{-}}3,6\text{\ensuremath{-}}{\mathrm{F}}_{2}\text{\ensuremath{-}}\mathrm{V}$ [=3-(2-chloro-3,6-difluorophenyl)-1,5-diphenylverdazyl], which is a rare model compound with an $S=\frac{1}{2}$ Heisenberg antiferromagnetic (HAF) honeycomb lattice. Ab initio molecular orbital calculations indicate two dominant AF interactions, forming a slightly distorted honeycomb lattice. We explain the magnetic susceptibility and the magnetization curve up to the saturation field based on the expected spin model using the quantum Monte Carlo method. In the low-temperature regions, we found a phase transition to an AF ordered state at about 0.77 K for the zero field and obtained the magnetic field-temperature phase diagram from the magnetic susceptibility and the specific heat for various magnetic fields. Through the analysis considering the effect of lattice distortion on magnetic behavior, we confirm that the lattice distortion of the present model is small enough that it does not affect the intrinsic behavior of the uniform $S=\frac{1}{2}$ HAF honeycomb lattice.

We have succeeded in synthesizing a new organic biradical F4BIPBNN [= 2,2′-(3,3′,5,5′-tetrafluorobiphenyl-4,4′-diyl)bis(4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide)] which forms an S = 1=2 Heisenberg three-dimensional honeycomb antiferromagnet. Each site of a honeycomb layer alternately couples with upper or lower layers, which results in the unique three-dimensional honeycomb network with four nearest neighbors. At zero magnetic field, antiferromagnetic long-range order has been observed below TN = 2.7 K. Magnetic susceptibility in both paramagnetic and antiferromagnetic states and the magnetization curves are well reproduced by quantum Monte Carlo calculations with three antiferromagnetic interactions in the range of 4.3 to 6.6 K. From the concave shape of the magnetization curve, the shrinkage of spin due to spin fluctuations is evaluated to approximately 30% with respect to its classical value. The phase diagram of magnetic field versus temperature was determined by heat capacity and magnetization. In the field region below 3 T, a slight increase of TN was observed, which reflects the effect of spin fluctuations., Dr. A. Arauzo from General Services for Research of University of Zaragoza is acknowledged. JC and FP acknowledge grant number MAT2015-68200-C2-2-P. This work was partly supported by JSPS KAKENHI Grant Number JP15H03695 for YH. This work was performed in part under the Inter-University Cooperative Research Program of the Institute for Materials Research, Tohoku University, and in Institute for Molecular Science, supported by Nanotechnology Platform Program (Molecule and Material Synthesis) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.

Dipeptidyl peptidases (DPPs) are crucial for the energy metabolism in Porphyromonas gingivalis, a Gram-negative proteolytic and asaccharolytic anaerobic rod causing chronic periodontitis. Three DPPs, DPPIV specific for Pro, DPP7 for hydrophobic residues and DPP11 for Asp/Glu at the P1 position, are expressed in the bacterium. Like DPP7, DPP11 belongs to the S46 protease family, and they share 38.7% sequence identity. Although DPP11 is preferential for hydrophobic residues at the P2 position, it has been reported that DPP7 has no preference at the P2 position. In the present study, we defined the detailed P2 substrate preference of DPP7 and the amino acid residue responsible for the specificity. DPP7 most efficiently hydrolyzed Met-Leu-dipeptidyl-4-methylcoumaryl-7-amide (MCA) carrying hydrophobic residues at the P1 position with kcat/Km of 10.62 ± 2.51 μM−1 s−1, while it unexpectedly cleaved substrates with hydrophilic (Gln, Asn) or charged (Asp, Arg) residues. Examination with 21 dipeptidyl MCA demonstrated that DPP7-peptidase activity was dependent on hydrophobicity of the P2- as well as P1-position residue, thus it correlated best with the sum of the hydrophobicity index of P1- and P2-amino acid residues. Hydrophobicity of the P1 and P2 positions ensured efficient enzyme catalysis by increasing kcat and lowering Km values, respectively. Substitution of hydrophobic residues conserved in the S46 DPP7/DPP11 family to Ala revealed that Phe664 of DPP7 and Phe671 of DPP11 primarily afforded hydrophobic P2 preference. A modeling study suggested that Phe664 and Gly666 of DPP7 and Phe671 and Arg673 of DPP11 being associated with the P2- and P1-position residues, respectively, are located adjacent to the catalytic Ser648/Ser655. The present results expand the substrate repertoire of DPP7, which ensures efficient degradation of oligopeptides in asaccharolytic bacteria., Highlights • Dipeptidyl peptidases are crucial for energy metabolism in Porphyromonas gingivalis. • P. gingivalis DPP7 prefers a hydrophobic amino acid residue at P2 position. • kcat/Km of DPP7 for Met-Leu-MCA is 10.62 ± 2.51 μM−1 s−1. • A hydrophobic P1 residue enhances kcat and a hydrophobic P2 residue lowers Km. • Phe664 of DPP7 and Phe671 of DPP11 primarily afford hydrophobic P2 preference.

We present the first experimental realization of an $S=2$ ferromagnetic-antiferromagnetic (F-AF) alternating chain in a new Mn-verdazyl complex [Mn(hfac)$_2$]$\cdot$($o$-Py-V) [hfac=1,1,1,5,5,5-hexafluoroacetylacetonate; $o$-Py-V=3-(2-pyridyl)-1,5-diphenylverdazyl]. Through the $ab$ $initio$ molecular orbital calculation, magnetization, and ESR measurements, this compound is confirmed to form an $S=2$ F-AF alternating chain with Ising anisotropy below about 100 K. Furthermore, we find an anomalous change in magnetization at 1/4 of the saturation value, which is probably a manifestation of the quantum nature of the system.

The glutamyl endopeptidase family of enzymes from staphylococci has been shown to be important virulence determinants of pathogenic family members, such as Staphylococcus aureus. Previous studies have identified the N-terminus and residues from positions 185-195 as potentially important regions that determine the activity of three members of the family. Cloning and sequencing of the new family members from Staphylococcus caprae (GluScpr) and Staphylococcus cohnii (GluScoh) revealed that the N-terminal Val residue is maintained in all family members. Mutants of the GluV8 enzyme from S. aureus with altered N-terminal residues, including amino acids with similar properties, were inactive, indicating that the Val residue is specifically required at the N-terminus of this enzyme family in order for them to function correctly. Recombinant GluScpr was found to have peptidase activity intermediate between GluV8 and GluSE from Staphylococcus epidermis and to be somewhat less specific in its substrate requirements than other family members. The 185-195 region was found to contribute to the activity of GluScpr, although other regions of the enzyme must also play a role in defining the activity. Our results strongly indicate the importance of the N-terminal and the 185-195 region in the activity of the glutamyl endopeptidases of staphylococci., Biological chemistry, 391(10), pp.1221-1232; 2010

Single crystals of a two-dimensional quantum spin system with geometric frustration lead to the observation of a ‘pinwheel’ valence-bond ground state. In this case, the distortion of the ideal kagome lattice structure helps to stabilize the quantum spin state. Determining ground states of correlated electron systems is fundamental to understanding unusual phenomena in condensed-matter physics. A difficulty, however, arises in a geometrically frustrated system in which the incompatibility between the global topology of an underlying lattice and local spin interactions gives rise to macroscopically degenerate ground states1, potentially prompting the emergence of quantum spin states, such as resonating valence bond2,3,4,5,6,7 and valence-bond solid8,9,10,11 (VBS). Although theoretically proposed to exist in a kagome lattice—one of the most highly frustrated lattices in two dimensions being comprised of corner-sharing triangles—such quantum-fluctuation-induced states have not been observed experimentally. Here we report the first realization of the ‘pinwheel’ VBS ground state in the S=1/2 deformed kagome lattice antiferromagnet Rb2Cu3SnF12 (refs 12, 13). In this system, a lattice distortion breaks the translational symmetry of the ideal kagome lattice and stabilizes the VBS state.

In magnetic field, KCuGaF6 can be mapped onto the quantum sine-Gordon model, for which low-energy elementary excitations are solitons, antisolitons and their bound states breathers. Using high-frequency, high-field ESR measurements, we observed these unusual magnetic excitations.

V8 protease (GluV8), a member of the glutamyl endopeptidase I family isolated from the V8 strain of Staphylococcus aureus, is widely used for proteome analysis because of its unique substrate specificity and resistance to detergents. We recently developed an Escherichia coli expression system for the production of GluV8 based on a technique that suppresses the autoproteolysis?the use of the prosequence of its homologue (GluSE) from Staphylococcus epidermidis as a chimeric form or the introduction of four substitutions in the prosequence of GluV8. In the current study, we refined this technique through five amino acid substitutions within the prosequence of GluV8 for complete suppression of the autodegradation. As a result, the recovery of GluV8 proform was enhanced to 20 fg/cell, which was comparable to the level of a constitutive inactive form of GluV8, indicating complete suppression of the autoproteolysis. This mutated propeptide was also effective for the expression of the mature sequence of the glutamyl endopeptidase from Staphylococcus warneri. The recombinant proteins were successfully converted to their active forms through a common cleavage mechanism mediated by thermolysin in vitro. This strategy may shed light on the way for the expression of the proteases that have been scarcely produced in E. coli to date., Analytical Biochemistry, 381(1), pp.74-80; 2008

The extracellular serine endopeptidase GluSE (EC 3.4.21.19) is considered to be one of the virulence factors of Staphylococcus epidermidis. The present study investigated maturation processing of native GluSE and that heterologously expressed in Escherichia coli. In addition to the 28-kDa mature protease, small amounts of proenzymes with molecular masses of 32, 30, and 29 kDa were identified in the extracellular and cell wall-associated fractions. We defined the pre (M1-A27)- and pro (K28-S66)-segments, and found that processing at the E32-S33 and D48-I49 bonds was responsible for production of the 30- and 29-kDa intermediates, respectively. The full-length form of C-terminally His-tagged GluSE was purified as three proenzymes equivalent to the native ones. These molecules possessing an entire or a part of the pro-segment were proteolytically latent and converted to a mature 28-kDa form by thermolysin cleavage at the S66-V67 bond. Mutation of the essential amino acid S235 suggested auto-proteolytic production of the 30- and 29-kDa intermediates. Furthermore, an undecapeptide (I56-S66) of the truncated pro-segment not only functions as an inhibitor of the protease but also facilitates thermolysin processing. These findings could offer clues to the molecular mechanism involved in the regulation of proteolytic activity of pathogenic proteases secreted from S. epidermidis., Biological Chemistry, 389(9), pp.1209-1217; 2008

V8 protease, a member of the glutamyl endopeptidase I family, of Staphylococcus aureus V8 strain (GluV8) is widely used for proteome analysis because of its unique substrate specificity and resistance to detergents. In this study, an Escherichia coli expression system for GluV8, as well as its homologue from Staphylococcus epidermidis (GluSE), was developed, and the roles of the prosegments and two specific amino acid residues, Val69 and Ser237, were investigated. C-terminal His(6)-tagged proGluSE was successfully expressed from the full-length sequence as a soluble form. By contrast, GluV8 was poorly expressed by the system as a result of autodegradation; however, it was efficiently obtained by swapping its preprosegment with that of GluSE, or by the substitution of four residues in the GluV8 prosequence with those of GluSE. The purified proGluV8 was converted to the mature form in vitro by thermolysin treatment. The prosegment was essential for the suppression of proteolytic activity, as well as for the correct folding of GluV8, indicating its role as an intramolecular chaperone. Furthermore, the four amino acid residues at the C-terminus of the prosegment were sufficient for both of these roles. In vitro mutagenesis revealed that Ser237 was essential for proteolytic activity, and that Val69 was indispensable for the precise cleavage by thermolysin and was involved in the proteolytic reaction itself. This is the first study to express quantitatively GluV8 in E. coli, and to demonstrate explicitly the intramolecular chaperone activity of the prosegment of glutamyl endopeptidase I.

We investigate the magnetic order of the buckled honeycomb lattice antiferromagnet ${\mathrm{Ba}}_{2}{\mathrm{NiTeO}}_{6}$ and its related antiferromagnet ${\mathrm{Ba}}_{3}{\mathrm{NiTa}}_{2}{\mathrm{O}}_{9}$ by neutron diffraction measurements. We observe magnetic Bragg peaks below the transition temperatures, and identify propagation vectors for these oxides. A combination of representation analysis and Rietveld refinement leads to a collinear magnetic order for ${\mathrm{Ba}}_{2}{\mathrm{NiTeO}}_{6}$ and a ${120}^{\ensuremath{\circ}}$ structure for ${\mathrm{Ba}}_{3}{\mathrm{NiTa}}_{2}{\mathrm{O}}_{9}$. We find that the spin model of the bilayer triangular lattice is equivalent to that of the two-dimensional buckled honeycomb lattice having magnetic frustration. We discuss the magnetic interactions and single-ion anisotropy of $\mathrm{Ni}^{2+}$ ions for ${\mathrm{Ba}}_{2}{\mathrm{NiTeO}}_{6}$ in order to clarify the origin of the collinear magnetic structures. Our calculation suggests that the collinear magnetic order of ${\mathrm{Ba}}_{2}{\mathrm{NiTeO}}_{6}$ is induced by the magnetic frustration and easy-axis anisotropy.

TlCuCl 3 is composed of spin dimers and has a gapped singlet ground state. This system undergoes antiferromagnetic orderings under both external magnetic field and hydrostatic pressure, which are described as Bose–Einstein condensation and softening of triplet excitations. An overview of the magnetic quantum phase transitions in TlCuCl 3 is given.

Elementary excitations of the $S=\frac{1}{2}$ one-dimensional antiferromagnet ${\mathrm{KCuGaF}}_{6}$ were investigated by inelastic neutron scattering in zero and finite magnetic fields perpendicular to the $(1,1,0)$ plane combined with specific heat measurements. ${\mathrm{KCuGaF}}_{6}$ exhibits no long-range magnetic ordering down to 50 mK despite the large exchange interaction $J/{k}_{\mathrm{B}}=103$ K. At zero magnetic field, well-defined spinon excitations were observed. The energy of the des Cloizeaux and Pearson [J. des Cloizeaux and J. J. Pearson, Phys. Rev. 128, 2131 (1962)] mode of the spinon excitations is somewhat larger than that calculated with the above exchange constant. This discrepancy is mostly ascribed to the effective $XY$ anisotropy arising from the large Dzyaloshinsky-Moriya [T. Moriya, Phys. Rev. 120, 91 (1960)] interaction with an alternating $\mathbit{D}$ vector. ${\mathrm{KCuGaF}}_{6}$ in a magnetic field is represented by the quantum sine-Gordon model, for which low-energy elementary excitations are composed of solitons and antisolitons and their bound states called breathers. Unlike the theoretical prediction, it was found that the energy of a soliton is smaller than that of the first breather, although the energy of the first breather coincides with that observed in a previous electron spin resonance measurement.

Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration. The realization of such systems is expected to provide a distinct platform for studying frustrated magnetism. Here, we present a spin-1/2 quantum pentagonal lattice in the new organic radical crystal α-2,6-Cl2-V [=α-3-(2,6-dichlorophenyl)-1,5-diphenylverdazyl]. Its unique molecular arrangement allows the formation of a partially corner-shared pentagonal lattice (PCPL). We find a clear 1/3 magnetization plateau and an anomalous change in magnetization in the vicinity of the saturation field, which originate from frustrated interactions in the PCPL.

The layered compound $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ is composed of a honeycomb lattice of magnetic ${\mathrm{Ru}}^{3+}$ ions with the $4{d}^{5}$ electronic state. We have investigated the magnetic properties of $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ via magnetization and specific heat measurements using single crystals. It was observed that $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ undergoes a structural phase transition at ${T}_{t}\phantom{\rule{0.16em}{0ex}}\ensuremath{\simeq}\phantom{\rule{0.16em}{0ex}}150$ K accompanied by fairly large hysteresis. This structural phase transition is expected to be similar to that observed in closely related ${\mathrm{CrCl}}_{3}$. The magnetizations and magnetic susceptibilities are strongly anisotropic, which mainly arise from the anisotropic $g$ factors, i.e., ${g}_{ab}\phantom{\rule{0.16em}{0ex}}\ensuremath{\simeq}\phantom{\rule{0.16em}{0ex}}2.5$ and ${g}_{c}\phantom{\rule{0.16em}{0ex}}\ensuremath{\simeq}\phantom{\rule{0.16em}{0ex}}0.4$ for magnetic fields parallel and perpendicular to the $ab$ plane, respectively. These $g$ factors and the obtained entropy indicate that the effective spin of ${\mathrm{Ru}}^{3+}$ is one-half, which results from the low-spin state. Specific heat data show that magnetic ordering occurs in four steps at zero magnetic field. The successive magnetic phase transitions should be ascribed to the competition among exchange interactions. The magnetic phase diagram for $H\phantom{\rule{0.16em}{0ex}}\ensuremath{\parallel}\phantom{\rule{0.16em}{0ex}}ab$ is obtained. We discuss the strongly anisotropic $g$ factors in $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ and deduce that the exchange interaction is strongly XY-like. $\ensuremath{\alpha}\ensuremath{-}{\mathrm{RuCl}}_{3}$ is magnetically described as a three-dimensionally coupled XY-like frustrated magnet on a honeycomb lattice.

The 70-kDa heat shock protein (Hsp70) is predominantly present intracellularly as a monomer, but a small population is converted to dimers and oligomers under certain conditions. In the present study, we investigated the dimeric structure of human inducible Hsp70. As reported earlier, the C-terminal client-binding domain (amino acids 382-641) was required for the dimerization. A 40-amino acid deletion in the client-binding domain from either the N-terminus or C-terminus greatly enhanced the dimerization potential of Hsp70. Limited proteolysis indicated that the dimer formed through truncation from the C-terminus had a conformation similar to that of the non-truncated form. Truncation experiments demonstrated that the client-binding sub-domain (amino acids 382-520) with its adjacent region up to amino acid 541 was not sufficient for the dimerization but that the region up to amino acid 561 was sufficient. Interestingly, the dimer formed through truncation from the C-terminus acquired a homomeric disulfide bridge at Cys574., Journal of biochemistry. 139(4), pp.677-687; 2006

Old hen tendon provides a model suitable for the study of calcification in an extracellular matrix. In the present study, we observed the mineralizing substances of hen tendon by scanning electron microscopy of plasma-osmium-coated specimens and by transmission electron microscopy of those processed by a plasma-polymerization film replica method. The mineralizing front area revealed a number of elliptical particles fused to each other and forming rod-like structures oriented parallel to collagen fibrils. The area of advanced mineralization possessed non-mineralizing cavities, in which tendon cells were likely to exist. At this site, we recognized a second form of mineral structure, one in which the crystals had a scale-like morphology and were deposited onto the major first-form mineral component. This crystal form was similar to hydroxyapatite synthesized under wet reaction conditions. These findings strongly suggest that the second form of mineral formed independent of collagen fibrils existed together with the predominant, collagen-dependent form of mineral. We speculate that cell membranes and an extremely slow mineralization process may contribute to the formation of this form of mineral during the mineralization process in the hen tendon.

Magnetization, specific heat and X-ray measurements have been carried out on Cs 2 Cu 3 ZrF 12 which is a candidate of a two-dimensional S = 1/2 Heisenberg Kagome antiferromagnet. A structural phase transition was observed at T t ≃ 210 K. The hexagonal unit cell is enlarged to 2a, 2a, c below T t . A jump was observed in the susceptibility at T t . The magnetic susceptibility obeys the Curie-Weiss law with the Weiss constants Θ = -355 K and Θ = -300 K above and below T,, respectively. Weak ferromagnetic behavior was observed below T wf ≃ 30 K. However, specific heat exhibits no anomaly at T wf .

Quantum antiferromagnet NH 4 CuCl 3 shows magnetization plateaus at 1/4 and 3/4 of the saturation magnetization. Specific heat measurements at ambient pressure and magnetization measurements under hydrostatic pressure were performed on NH 4 CuCl 3 in magnetic fields. From specific heat measurements, we obtained the detailed magnetic phase diagram below 9 T, which includes the lower edge field H c1 of 1/4 plateau. The phase boundary just below H c1 can be described by a power low, H c1 - H N (T) T Φ with Φ = 2, where H N (T) is the transition field at temperature T. Magnetic susceptibility measurements under pressure revealed reentrant quantum phase transitions, such that the gapless ground state at zero field changes into gapped state with increasing pressure, and further into gapless state again.

An attempt to substitute Co 2+ , Mn 2+ for Pd 2+ was performed to yield dilute kagome lattice magnetism of S = 1/2 on a ternary transition metal chalocogenide Rb 2 Pd 3 S 4 . This compound takes a crystal structure, Pd sites of which constitute kagome lattice nets. Because the divalent Pd 2+ (4d) 8 's on the kagome lattice are in a low-spin state of spin-less owing to specific characteristics of the crystal field influencing on the Pd sites. Magnetic properties of specimens thus obtained were examined through magnetic susceptibility, ESR and specific heat measurements. Several data were obtained for confirming the syntheses of S = 1/2 systems in spite of dilute magnetic ones with substitutional ratio x's below the site percolation threshold x p = 0.62 of the kagome lattice.

Magnetization measurements under hydrostatic pressure were performed on S = 1/2 coupled dimer systems TlCuCl 3 and KCuCl 3 under magnetic field H parallel to the [2,0,1] direction. With increasing applied pressure P, the gap in TlCuCl 3 decreases and closes completely at P c = 0.42 ± 0.05 kbar. TlCuCl 3 undergoes pressure-induced quantum phase transition. The gap and Neel temperature are presented as functions of pressure. KCuCl 3 also undergoes pressure-induced quantum phase transition at P c ∼ 8.8 kbar. Pressure dependence of intra- and interdimer interactions in KCuCl 3 are presented.

The field induced magnetic phase transitions of Cs 2 CuBr 4 were investigated by means of magnetization process and neutron scattering experiments. Cs 2 CuBr 4 should be characterized as S = 1/2 two-dimensional triangular antiferromagnet. Below the ordering temperature T N = 1.4 K, the Spin structure is the helical incommensurate structure almost within the triangular lattice plane. In the field direction within the triangular lattice plane, Cs 2 CuBr 4 exhibits the magnetization plateaux at one-third and two-thirds of the saturation magnetization. The spin structure in the one-third plateau phase is found to be almost collinear up-up-down structure which should be stabilized by quantum fluctuation as predicted by the theoretical studies.

Magnetic measurements under high pressures have been performed on the hexagonal ABX 3 type antiferromagnets, CsFeCl 3 , CsNiCl 3 and RbNiCl 3 to investigate the pressure effect on the magnetic phase transitions. CsFeCl 3 has the singlet ground state due to the large single-ion anisotropy of the easy-plane type at ambient pressure. Above the critical pressure P c ≃ 0.9 GPa, CsFeCl 3 exhibits the long range magnetic ordering at zero field as the result of the collapse of the energy gap between the singlet state and the lowest excited doublet. CsNiCl 3 and RbNiCl 3 having the easy-axis type magnetic anisotropy undergo the successive phase transitions in the temperature variations and exhibit the spin-flop phase transition in the field parallel to the c-axis. With increasing pressure, the temperature range of the collinear intermediate phase and the spin-flop field H SF are enhanced. This fact indicates that the easy-axis anisotropies of CsNiCl 3 and RbNiCl 3 are enhanced by the pressure as compared with the increase of the intra- and inter-chain interactions.

We give an overview of our studies on the electron spin resonance (ESR) in the hexagonal triangular antiferromagnets of ABX 3 type using millimeter and submillimeter waves and static and pulsed high magnetic fields. Novel ESR modes, which cannot be understood by the conventional theory of the antiferromagnetic resonance, were observed. Examples of this include that there exists the gapless excitation even for the easy-axis anisotropy. The ESR modes can be classified by the signs of the exchange interaction J 0 along the c-axis and the anisotropy. The ESR modes were calculated within the framework of the mean-field approximation using three-sublattice and six-sublattice models for the ferromagnetic and antiferromagnetic J 0 interaction, respectively. The experimental results were well described by the present calculations.

The alpha isoform of human 90-kDa heat shock protein (HSP90alpha) is composed of three domains: the N-terminal (residues 1-400); middle (residues 401-615) and C-terminal (residues 621-732). The middle domain is simultaneously associated with the N- and C-terminal domains, and the interaction with the latter mediates the dimeric configuration of HSP90. Besides one in the N-terminal domain, an additional client-binding site exists in the C-terminal domain of HSP90. The aim of the present study is to elucidate the regions within the C-terminal domain responsible for the bindings to the middle domain and to a client protein, and to define the relationship between the two functions. A bacterial two-hybrid system revealed that residues 650-697 of HSP90alpha were essential for the binding to the middle domain. An almost identical region (residues 657-720) was required for the suppression of heat-induced aggregation of citrate synthase, a model client protein. Replacement of either Leu665-Leu666 or Leu671-Leu672 to Ser-Ser within the hydrophobic segment (residues 662-678) of the C-terminal domain caused the loss of bindings to both the middle domain and the client protein. The interaction between the middle and C-terminal domains was also found in human 94-kDa glucose-regulated protein. Moreover, Escherichia coli HtpG, a bacterial HSP90 homologue, formed heterodimeric complexes with HSP90alpha and the 94-kDa glucose-regulated protein through their middle-C-terminal domains. Taken together, it is concluded that the identical region including the hydrophobic segment of the C-terminal domain is essential for both the client binding and dimer formation of the HSP90-family molecular chaperone and that the dimeric configuration appears to be similar in the HSP90-family proteins., European journal of biochemistry, 270(1), pp.146-154; 2003

The alpha isoform of human 90-kDa heat shock protein (HSP90alpha) is composed of three domains: the N-terminal (residues 1-400); middle (residues 401-615) and C-terminal (residues 621-732). The middle domain is simultaneously associated with the N- and C-terminal domains, and the interaction with the latter mediates the dimeric configuration of HSP90. Besides one in the N-terminal domain, an additional client-binding site exists in the C-terminal domain of HSP90. The aim of the present study is to elucidate the regions within the C-terminal domain responsible for the bindings to the middle domain and to a client protein, and to define the relationship between the two functions. A bacterial two-hybrid system revealed that residues 650-697 of HSP90alpha were essential for the binding to the middle domain. An almost identical region (residues 657-720) was required for the suppression of heat-induced aggregation of citrate synthase, a model client protein. Replacement of either Leu665-Leu666 or Leu671-Leu672 to Ser-Ser within the hydrophobic segment (residues 662-678) of the C-terminal domain caused the loss of bindings to both the middle domain and the client protein. The interaction between the middle and C-terminal domains was also found in human 94-kDa glucose-regulated protein. Moreover, Escherichia coli HtpG, a bacterial HSP90 homologue, formed heterodimeric complexes with HSP90alpha and the 94-kDa glucose-regulated protein through their middle-C-terminal domains. Taken together, it is concluded that the identical region including the hydrophobic segment of the C-terminal domain is essential for both the client binding and dimer formation of the HSP90-family molecular chaperone and that the dimeric configuration appears to be similar in the HSP90-family proteins.

At the primary structure level, the 90-kDa heat shock protein (HSP90) is composed of three regions: the N-terminal (Met(1)-Arg(400)), middle (Glu(401)-Lys(615)), and C-terminal (Asp(621)-Asp(732)) regions. In the present study, we investigated potential subregion structures of these three regions and their roles. Limited proteolysis revealed that the N-terminal region could be split into two fragments carrying residues Met(1) to Lys(281) (or Lys(283)) and Glu(282) (or Tyr(284)) to Arg(400). The former is known to carry the ATP-binding domain. The fragments carrying the N-terminal two-thirds (Glu(401)-Lys(546)) and C-terminal one-third of the middle region were sufficient for the interactions with the N- and C-terminal regions, respectively. Yeast HSC82 that carried point mutations in the middle region causing deficient binding to the N-terminal region could not support the growth of HSP82-depleted cells at an elevated temperature. Taken together, our data show that the N-terminal and middle regions of the HSP90 family protein are structurally divided into two respective subregions. Moreover, the interaction between the N-terminal and middle regions is essential for the in vivo function of HSP90 in yeast., Journal of Biological Chemistry, Vol. 277, Issue 38, 34959-34966, September 20, 2002

We have measured the magnetization of the organic compound BIP-BNO (3,5'-bis(N-tert-butylaminoxyl)-3',5-dibromobiphenyl) up to 76 T where the magnetization is saturated. The S = 1/2 antiferromagnetic Heisenberg two-leg spin-ladder model accounts for the obtained experimental data regarding the magnetization curve, which is clarified using the quantum Monte Carlo method. The exchange constants on the rung and the side rail of the ladder are estimated to be J(rung)/kB = 65.7 K and J(leg)/kB = 14.1 K, respectively, deeply in the strong coupling region: J(rung)/J(leg) > 1., 8 pages, 2 figures

Severe periodontitis is known to aggravate diabetes mellitus, though molecular events related to that link have not been fully elucidated. Porphyromonas gingivalis, a major pathogen of periodontitis, expresses dipeptidyl peptidase 4 (DPP4), which is involved in regulation of blood glucose levels by cleaving incretins in humans. We examined the enzymatic characteristics of DPP4 from P. gingivalis as well as two other periodontopathic bacteria, Tannerella forsythia and Prevotella intermedia, and determined whether it is capable of regulating blood glucose levels. Cell-associated DPP4 activity was found in those microorganisms, which was effectively suppressed by inhibitors of human DPP4, and molecules sized 73 kDa in P. gingivalis, and 71 kDa in T. forsythia and P. intermedia were immunologically detected. The kcat/Km values of recombinant DPP4s ranged from 721 ± 55 to 1283 ± 23 μM-1sec-1 toward Gly-Pro-4-methylcoumaryl-7-amide (MCA), while those were much lower for His-Ala-MCA. MALDI-TOF MS analysis showed the His/Tyr-Ala dipeptide release from the N-termini of incretins, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide, respectively, with the action of microbial DPP4. Moreover, intravenous injection of DPP4 into mice decreased plasma active GLP-1 and insulin levels, accompanied by a substantial elevation in blood glucose over the control after oral glucose administration. These results are the first to show that periodontopathic bacterial DPP4 is capable of modulating blood glucose levels the same as mammalian DPP4, thus the incidence of periodontopathic bacteremia may exacerbate diabetes mellitus via molecular events of bacterial DPP4 activities., Infection and Immunity, 85(9), e00277-17; 2017

An antiferromagnetic system on a 2-D triangular lattice leads to geometric topological frustration. This ideal system has been the subject of theoretical investigations. One experimental realization of this system is the compound Cs2CuCl4. Various magnetization, heat capacity, neutron scattering and NMR studies have identified several magnetic transitions when the magnetic field is applied along one of the three principal axes. The current work investigates the evolution of these phases at intermediate angles as the crystal is rotated relative to the magnetic field. These phases were investigated using a novel rotating calorimeter allowing complete coverage of the experimental parameter space. New magnetic phases only existing at intermediate angles have been found.