The solution structure of Escherichia coli Wzb reveals a novel substrate recognition mechanism of prokaryotic low molecular weight protein-tyrosine phosphatases.
ABSTRACT Low molecular weight protein-tyrosine phosphatases (LMW-PTPs) are small enzymes that ubiquitously exist in various organisms and play important roles in many biological processes. In Escherichia coli, the LMW-PTP Wzb dephosphorylates the autokinase Wzc, and the Wzc/Wzb pair regulates colanic acid production. However, the substrate recognition mechanism of Wzb is still poorly understood thus far. To elucidate the molecular basis of the catalytic mechanism, we have determined the solution structure of Wzb at high resolution by NMR spectroscopy. The Wzb structure highly resembles that of the typical LMW-PTP fold, suggesting that Wzb may adopt a similar catalytic mechanism with other LMW-PTPs. Nevertheless, in comparison with eukaryotic LMW-PTPs, the absence of an aromatic amino acid at the bottom of the active site significantly alters the molecular surface and implicates Wzb may adopt a novel substrate recognition mechanism. Furthermore, a structure-based multiple sequence alignment suggests that a class of the prokaryotic LMW-PTPs may share a similar substrate recognition mechanism with Wzb. The current studies provide the structural basis for rational drug design against the pathogenic bacteria.
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ABSTRACT: Antibiotics are certainly beneficial to treat the bacterial infection. However, inappropriate use puts patients at danger for avoidable adverse drug reactions. This inappropriate use accelerates the emergence of resistance and potentially increases overall health-care costs. In oriental pharmacology, herbal medicines had been used as an antibiotic drug, but its antibiotic mechanism has not yet been proved completely. Here, we studied the antibiotic effects of Agrimonia pilosa on E. coli O157:H7. Especially, it is noteworthy that the antibiotic efficacy of the herb extract on three proven targets for a main antibiotic drug: bacterial cell wall biosynthesis, protein synthesis and DNA replication and repair. The results show the antibiotic effects through the inhibition of bacterial cell wall synthesis, folic acid synthesis, and multidrug efflux. Keywords Agrimonia pilosa –Antibiotic– folA–Cell wall inhibition– cys sulfur metabolismMolecular and Cellular Toxicology 04/2012; 7(3):299-310. · 0.72 Impact Factor
- Journal of Medicinal Chemistry 01/2012; 55(1):2-22. · 5.61 Impact Factor
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ABSTRACT: The cyclic process of auto-phosphorylation of the C-terminal tyrosine cluster (YC) of a BY-kinase (Bacterial tYrosine kinase), and its subsequent dephosphorylation following interactions with a counteracting tyrosine phosphatase, regulates diverse physiological processes including the biosynthesis and export of polysaccharides responsible for the formation of biofilms or virulence-determining capsules. We provide here the first detailed insight into this hitherto uncharacterized regulatory interaction at residue-specific resolution using Escherichia coli Wzc, a canonical BY-kinase, and its opposing tyrosine phosphatase, Wzb. The phosphatase Wzb utilizes a surface distal to the catalytic elements of the kinase, Wzc, to dock onto its catalytic domain (WzcCD). WzcCD binds in a largely YC-independent fashion near the Wzb catalytic site, inducing allosteric changes therein. YC-dephosphorylation is proximity-mediated and reliant on the elevated concentration of phosphorylated-YC near the Wzb active site resulting from WzcCD docking. Wzb principally recognizes the phosphate of its phospho-tyrosine substrate, and further stabilizes the tyrosine moiety through ring stacking interactions with a conserved active-site tyrosine.Journal of Biological Chemistry 03/2013; · 4.65 Impact Factor