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SarA is a global transcription regulator in S. aureus which regulates the expression of over 120 genes related to quorum sensing, biofilm synthesis, drug resistance and many other important physiological processes during host infection. SarA can bind to the promoter region of agr and other target genes to activate or repress the transcription. The crystal structure of SarA uncovered a MarR protein-like conformation with two symmetrical winged helix domains, while its DNA binding mechanism is still unknown. We have constructed a monomeric DNA binding domain of SarA (SarAΔN19) for the study of the interaction between SarA and DNA with NMR spectroscopy. Here, we report the 1H, 13C and 15N NMR assignment of SarAΔN19/DNA complex which is the first step towards further structure and function analysis. [ABSTRACT FROM AUTHOR]

H-REV107-like family proteins TIG3 and H-REV107 are class II tumor suppressors. Here we report that the C-terminal domains (CTDs) of TIG3 and H-REV107 can induce HeLa cell death independently. The N-terminal domain (NTD) of TIG3 enhances the cell death inducing ability of CTD, while NTD of H-REV107 plays an inhibitory role. The solution structure of TIG3 NTD is very similar to that of H-REV107 in overall fold. However, the CTD binding regions on NTD are different between TIG3 and H-REV107, which may explain their functional difference. As a result, the flexible main loop of H-REV107, but not that of TIG3, is critical for its NTD to modulate its CTD in inducing cell death. [ABSTRACT FROM AUTHOR]

Abstract: H-REV107 is a Ca2+-independent phospholipase A1/2, and it is also a pro-apoptosis protein belonging to the novel class II tumor suppressor family, H-REV107-like family. Here we report the solution structure of the N-terminal catalytic domain of human H-REV107, which has a similar architecture to classical NlpC/P60 domains, even though their fold topologies are different due to circular permutation in the primary sequence. The phospholipase active site possesses a structurally conserved Cys–His–His catalytic triad as found in NlpC/P60 peptidases, indicating H-REV107 should adopt a similar catalytic mechanism towards phospholipid substrates to that of NlpC/P60 peptidases towards peptides. As H-REV107 is highly similar to lecithin retinol acyltransferase, our study also provides structural insight to this essential enzyme in retinol metabolism. [ABSTRACT FROM AUTHOR]

Human H-REV107 protein is the representative of a novel class II tumor suppressor family, which is lost in tumor cells and can induce cell death after restoration. The NMR assignments of the H-REV107 N-terminal domain are essential for its solution structure determination. [ABSTRACT FROM AUTHOR]

Bacterial thiol peroxidases (Tpxs) are antioxidant enzymes which exist in various bacteria. Tpxs reduce the lipid hydroperoxides to protect the membrane lipid from destruction by reactive oxygen species. Tpxs are essential enzymes for bacterial anaerobic growth. Herein, we report the resonance assignments of 1H, 13C, and 15N atoms in both the reduced and oxidized forms of Bacillus subtilis Tpx. [ABSTRACT FROM AUTHOR]

Abstract: Escherichia coli HypC plays an important role in the maturation process of the pre-maturated HycE, the large subunit of hydrogenase 3. It serves as an iron transfer as well as a chaperone protein during the maturation process of pre-HycE, and interacts with both HypD and HycE. The N-terminal cysteine residue of HypC plays a key role in the protein–protein interactions. Here, we present the three-dimensional structure of E. coli HypC, the first solution structure of HupF/HypC family. Our result demonstrates that E. coli HypC consists of a typical OB-fold β-barrel with two C-terminal helixes. Sequence alignment and structural comparison reveal that the hydrophobic region on the surface of E. coli HypC, as well as the highly flexible C-terminal helixes, may involve in the interactions of E. coli HypC with other proteins. [Copyright &y& Elsevier]

The main protease (M) of severe acute respiratory syndrome coronavirus (SARS-CoV) plays an essential role in the extensive proteolytic processing of the viral polyproteins (pp1a and pp1ab), and it is an important target for anti-SARS drug development. SARS-CoV M is composed of a catalytic N-terminal domain and an α-helical C-terminal domain linked by a long loop. Even though the N-terminal domain of SARS-CoV M adopts a similar chymotrypsin-like fold as that of piconavirus 3C protease, the extra C-terminal domain is required for SARS-CoV M to be enzymatically active. Here, we reported the NMR assignments of the SARS-CoV M N-terminal domain alone, which are essential for its solution structure determination. [ABSTRACT FROM AUTHOR]

Rhodanese catalyzes the sulfur-transfer reaction in which a sulfur atom is transferred from thiosulfate to cyanide by a double-displacement mechanism. During the reaction, a persulfide-intermediate form of rhodanese is generated by the reaction of a conserved active cysteine residue with thiosulfate. Escherichia coli GlpE is a prototype for the single-domain rhodanese superfamily. Though there are some studies on rhodaneses, the molecular mechanism of the catalytic activity of rhodaneses is still unclear. Herein, we report the resonance assignments of H, C and N atoms of E. coli GlpE, which provides the basis for further structural, dynamic and functional studies of rhodaneses using NMR technique. [ABSTRACT FROM AUTHOR]

Rhodanese domain is a ubiquitous structural module commonly found in bacterial, archaeal and eukaryotic cells. Growing evidence indicates that rhodanese domains act as the carrier of reactive sulfur atoms by forming persulfide intermediates in distinct metabolic pathways. YgaP, a membrane protein consisting of a rhodanese domain and a C-terminal transmembrane segment, is the only membrane-associated rhodanese in Escherichia coli. Herein, we report the resonance assignments of H, C and N atoms of rhodanese domain of YgaP. Totally, chemical shifts of more than 95% of the atoms were assigned. [ABSTRACT FROM AUTHOR]

enate reductases (ArsC) are a group of enzymes that play essential roles in biological arsenic detoxification pathways by catalyzing the intracellular reduction of arsenate to arsenite, which is subsequently extruded from the cells by specific transport systems. The ArsC protein from cyanobacterium Synechocystis sp. strain PCC 6803 (SynArsC) is related to the thioredoxin-dependent ArsC family, but uses the glutathione/glutaredoxin system for arsenate reduction. Therefore, it is classified to a novel thioredoxin/glutaredoxin hybrid arsenate reductase family. Herein we report the chemical shift assignments of H, C and N atoms for the reduced form of SynArsC, which provides a starting point for further structural analysis and elucidation of its enzymatic mechanism. [ABSTRACT FROM AUTHOR]

Escherichia coli HybE is a chaperone of hydrogenase-2 and plays a critical role in coordinating the assembly and export of the HybO and HybC subunits of hydrogenase-2. Previous studies indicated that the quality-control during the assembly and export of the HybO-HybC by the Tat pathway was putatively performed by HybE. However, the molecular basis of the biological function of HybE remains unknown. The structural information is essential in order to obtain functional insights of HybE. Here we report the backbone and sidechain resonance assignments of 1H, 13C and 15 N atoms in E. coli HybE. [ABSTRACT FROM AUTHOR]

The mRNA degradation is an important regulatory mechanism which controls gene expression by limiting the number of translation times. Previous studies demonstrated that this process is essential for organisms. Escherichia coli RNA pyrophosphohydrolase (RppH) is an enzyme that triggers mRNA degradation by removing the 5′ pyrophosphate, which is a rate-determining step. In order to understand the molecular mechanism of the biological function, the structural information of RppH is required. Herein, we report the resonance assignments of 1H, 15N, 13C atoms of the E. coli RppH. [ABSTRACT FROM AUTHOR]

GSP13 encoded by gene yugI is a general stress protein in Bacillus subtilis. The NMR assignments of the protein are essential for its structure determination. [ABSTRACT FROM AUTHOR]

The ζ-COP is one subunit of the COP I coatomer, which mediates the protein trafficking from the cis-Golgi complex to the endoplasmic reticulum and also functions in the intra-Golgi trafficking. The NMR assignments of the ζ-COP are essential for its solution structure determination. [ABSTRACT FROM AUTHOR]

Abstract: The bacterial phosphoenolpyruvate-dependent sugar phosphotransferase system (PEP-PTS) is essential in the coupled transportation and phosphorylation of various types of carbohydrates. The CmtAB proteins of Escherichia coli are sequentially similar to the mannitol-specific phosphotransferase MtlA. The CmtB protein corresponds to the phosphotransferase enzyme IIA component. Here we report the solution structure of CmtB from E. coli at high resolution by NMR spectroscopy. The results show that CmtB adopts a globular fold consisting of a central mixed five-strand β-sheet flanked by seven helices at both sides. Structural comparison with the IIA domain of MtlA (IIAMtl) reveals high overall similarity, while notable conformational differences at the active site are observed. The active site pocket of CmtB appears to be wider, and the hydrophobic regions around it is larger compared to IIAMtl. Further, the essential arginine residue at the active site of IIAMtl is substituted by a serine in CmtB. Instead, the active pocket of CmtB contains another arginine at a distinct position, suggesting different molecular mechanisms for phosphoryl transfer. [Copyright &y& Elsevier]

Abstract: COP-I-coated vesicles are protein and lipid carriers that mediate intra-Golgi transport and transport from the cis-Golgi complex to the endoplasmic reticulum in cells. The coatomer of the vesicles coat is comprised of seven subunits: α-COP, ɛ-COP, β′-COP, β-COP, γ-COP, δ-COP, and ζ-COP. Here we report the solution structure of a truncated form (residues 1–149; ζ-COP149) of human ζ-COP (total 177 residues). It is the first three-dimensional structure of a “core” subunit of the COP I F-subcomplex. The structure of ζ-COP149 mainly consists of a disordered N-terminal tail, a five-stranded antiparallel β-sheet, a two-stranded antiparallel β-sheet, and five α-helices. The global folding of ζ-COP149 is very similar to the crystal structures of AP1-σ1 and AP2-σ2, directly demonstrating the structural similarity between the “core” subunits of the COP I F-subcomplex and adaptor protein complexes. Through structural comparison and mutagenesis study, we have also demonstrated that the heterodimers of ζ-COP149 and γ-COP have packing interfaces and relative subunit orientations similar to those of AP2-σ2 and AP2-α heterodimers. These results provide direct evidence supporting the previous proposal that the COP I F-subcomplex and adaptor protein complexes have similar tertiary and quaternary structures. [Copyright &y& Elsevier]

Abstract: Bacterial thiol peroxidase (Tpx) is the periplasmic antioxidant enzyme widely distributed in most bacterial species, which catalyzes the reduction of lipid hydroperoxide in vivo. Tpx belongs to the atypical 2-Cys peroxiredoxin (Prx) family and utilizes two active cysteine residues during the redox reaction. Although several crystal structures of Tpx are available, no pair of the redox structures reported thus far. Therefore, the conformational changes coupled to the catalytic reaction remain unclear. Herein, we report the solution structures of Bacillus subtilis Tpx in both the reduced and oxidized forms, the first pair of Tpx structures. The overall structures of both forms are very similar, however, significant differences at the active regions around the CP and CR residues were observed. In particular, a helix-to-coil transition was observed at the CR region between the two forms. Our study reveals a dynamic picture of the conformational switch coupled to the redox reaction, thus provides further insights in understanding the catalytic mechanism of bacterial Tpx. [Copyright &y& Elsevier]

Abstract: PmrA/PmrB and PhoP/PhoQ are a pair of two-component systems (TCSs) that allow the Gram-negative bacteria to survive the cationic antimicrobial peptide polymyxin B. The two TCSs are linked by the polymyxin resistance protein, PmrD. The PhoP-activated PmrD protects the phosphorylated response regulator PmrA from dephosphorylation, and promotes the transcription of PmrA-activated genes responsible for polymyxin resistance. PmrD is the first protein identified to mediate the connectivity between two TCSs by protecting the phosphorylated response regulator of the downstream TCS. PmrD shows no homology to proteins with known structures. We present here the solution structure of PmrD from Escherichia coli, the first three-dimensional structure of the PmrD family. Our study provides the structural basis of the novel interacting mechanism of bacterial two-component signal-transduction systems. [Copyright &y& Elsevier]

Abstract: The bacterial chemotaxis adaptor protein CheW physically links the chemoreceptors (MCPs) and the histidine kinase CheA. Extensive investigations using bacterium Escherichia coli have established the central role of CheW in the MCP-modulated activation of CheA. Here we report the solution structure of CheW from E. coli determined by NMR spectroscopy. The results show that E. coli CheW shares an overall fold with previously reported structure of CheW from Thermotoga maritima, whereas local conformational deviations are observed. In particular, the C-terminal α-helix is considerably longer in E. coli CheW and appears to shrink the active binding pocket with CheA. Our study provides the structural basis for further investigations in E. coli chemotaxis. [Copyright &y& Elsevier]