Dataset Information

Active-site dynamics of SpvC virulence factor from Salmonella typhimurium and density functional theory study of phosphothreonine lyase catalysis.

ABSTRACT: The newly discovered SpvC effector protein from Salmonella typhimurium interferes with the host immune response by dephosphorylating mitogen-activated protein kinases (MAPKs) with a beta-elimination mechanism. To understand this unique phosphothreonine lyase catalysis, the dynamics of the enzyme-substrate complex of the SpvC effector is investigated with a 3.2 ns molecular dynamics simulation, which reveals that the phosphorylated peptide substrate is tightly held in the active site by a hydrogen bond network and the lysine general base is positioned for the abstraction of the alpha hydrogen. The catalysis is further modeled with density functional theory (DFT) in a truncated active-site model at the B3LYP/6-31+G(d,p) level of theory. The DFT calculations indicate the reaction proceeds via a single transition state, featuring a concerted proton abstraction from the alpha-carbon by Lys136 and beta-elimination of the phosphate leaving group. Key kinetic isotopic effects are predicted based on the truncated active-site model.

SUBMITTER: Smith GK

PROVIDER: S-EPMC2783390 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature

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Active-site dynamics of SpvC virulence factor from Salmonella typhimurium and density functional theory study of phosphothreonine lyase catalysis.

Smith Gregory K GK Ke Zhihong Z Hengge Alvan C AC Xu Dingguo D Xie Daiqian D Guo Hua H

The journal of physical chemistry. B 20091101 46

The newly discovered SpvC effector protein from Salmonella typhimurium interferes with the host immune response by dephosphorylating mitogen-activated protein kinases (MAPKs) with a beta-elimination mechanism. To understand this unique phosphothreonine lyase catalysis, the dynamics of the enzyme-substrate complex of the SpvC effector is investigated with a 3.2 ns molecular dynamics simulation, which reveals that the phosphorylated peptide substrate is tightly held in the active site by a hydroge ...[more]

PMID: 19715325

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Project description:BACKGROUND:Salmonella enterica subspecies enterica is an animal and zoonotic pathogen of global importance. Cattle are a significant reservoir of human non-typhoidal salmonellosis and can suffer enteric and systemic disease owing to the ability of Salmonella to survive within the bovine lymphatic system and intestines. Contamination of food can occur due to the incorporation of contaminated peripheral lymph nodes or by direct contamination of carcasses with gut contents. It is essential to understand the mechanisms used by Salmonella to enter and persist within the bovine lymphatic system and how they differ from those required for intestinal colonization to minimize zoonotic infections. RESULTS:Transposon-directed insertion site sequencing (TraDIS) was applied to pools of mutants recovered from mesenteric lymph nodes (MLNs) draining the distal ileum of calves after oral inoculation with a library of 8550 random S. Typhimurium mini-Tn5Km2 mutants in pools of 475 mutants per calf. A total of 8315 mutants representing 2852 different genes were detected in MLNs and their in vivo fitness was calculated. Using the same improved algorithm for analysis of transposon-flanking sequences, the identity and phenotype of mutants recovered from the distal ileal mucosa of the same calves was also defined, enabling comparison with previously published data and of mutant phenotypes across the tissues. Phenotypes observed for the majority of mutants were highly significantly correlated in the two tissues. However, 32 genes were identified in which transposon insertions consistently resulted in differential fitness in the ileal wall and MLNs, suggesting niche-specific roles for these genes in pathogenesis. Defined null mutations affecting ptsN and spvC were confirmed to result in tissue-specific phenotypes in calves, thus validating the TraDIS dataset. CONCLUSIONS:This validation of the role of thousands of Salmonella genes and identification of genes with niche-specific roles in a key target species will inform the design of control strategies for bovine salmonellosis and zoonotic infections, for which efficacious and cross-protective vaccines are currently lacking.

Dataset Information

Active-site dynamics of SpvC virulence factor from Salmonella typhimurium and density functional theory study of phosphothreonine lyase catalysis.

Publications

Active-site dynamics of SpvC virulence factor from Salmonella typhimurium and density functional theory study of phosphothreonine lyase catalysis.

Similar Datasets

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