3tnd

Crystal structure of Shigella flexneri VapBC toxin-antitoxin complex

spinqualitylabelsall models 3tnd, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3tnd is a 8 chain structure with sequence from "shigella_paradysenteriae"_weldin_1927 "shigella paradysenteriae" weldin 1927. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NA, SO4 Gene: CP0245, mvpA, stborf2, vapC ("Shigella paradysenteriae" Weldin 1927), CP0246, mvpT, vapB ("Shigella paradysenteriae" Weldin 1927) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [VAPC_SHIFL] Toxic component of a toxin-antitoxin (TA) module. A tRNA-(fMet) endonuclease, it cleaves both charged and uncharged tRNA-(fMet) between positions 38 and 39 at the anticodon stem-loop boundary. Does not cleave tRNA(Met), tRNA(Arg2), tRNA(His), tRNA(Leu), tRNA(Phe) tRNA(Thr1), tRNA(Tyr) or tRNA(Val). Overexpression in E.coli inhibits translation, leads to loss of cell growth and degradation of tRNA(fMet); these effects are neutralized by expression of cognate antitoxin VapB. The VapB/VapC complex probably regulates transcription of its own promoter. Ectopic overexpression in E.coli induces the YoeB toxin, but this is not the cause of VapC toxicity. [VAPB_SHIFL] Antitoxin component of a toxin-antitoxin (TA) module. Upon expression in E.coli neutralizes the effect of cognate toxin VapC. The VapB/VapC complex probably regulates transcription of its own promoter. Publication Abstract from PubMed Toxin-antitoxin (TA) loci are common in archaea and prokaryotes and allow cells to rapidly adapt to changing environmental conditions through release of active regulators of metabolism. Many toxins are endonucleases that target cellular mRNA and tRNAs, while the antitoxins tightly wrap around the toxins to inhibit them under normal circumstances. The antitoxins also bind to operators in the promoter regions of the cognate TA operon and thereby regulate transcription. For enteric vapBC TA loci, the VapC toxins specifically cleave tRNA(fMet) and thus down-regulate protein synthesis. Here, we describe the crystal structure of the intact Shigella flexneri VapBC TA complex, determined to 2.7 A resolution. Both in solution and in the crystal structure, four molecules of each protein combine to form a large and globular hetero-octameric assembly with SpoVT/AbrB-type DNA-binding domains at each end and a total molecular mass of about 100 kDa. The structure gives new insights into the inhibition of VapC toxins by VapB and provides the molecular basis for understanding transcriptional regulation through VapB dimerization. Crystal Structure of the VapBC Toxin-Antitoxin Complex from Shigella flexneri Reveals a Hetero-Octameric DNA-Binding Assembly.,Dienemann C, Boggild A, Winther KS, Gerdes K, Brodersen DE J Mol Biol. 2011 Oct 20. PMID:22037005 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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