1vj7

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Revision as of 02:46, 21 November 2007

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spinqualitylabelsall models 1vj7, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of the bifunctional catalytic fragment of RelSeq, the RelA/SpoT homolog from Streptococcus equisimilis.

Overview

Enzymes of the Rel/Spo family enable bacteria to survive prolonged periods, of nutrient limitation by producing an intracellular signaling alarmone, (p)ppGpp, which triggers the so-called stringent response. Both the, synthesis of (p)ppGpp from ATP and GDP(GTP), and its hydrolysis to, GDP(GTP) and pyrophosphate, are catalyzed by Rel/Spo proteins. The 2.1 A, crystal structure of the bifunctional catalytic fragment of the Rel/Spo, homolog from Streptococcus dysgalactiae subsp. equisimilis, Rel(Seq), reveals two conformations of the enzyme corresponding to known reciprocal, activity states: (p)ppGpp-hydrolase-OFF/(p)ppGpp-synthetase-ON and, hydrolase-ON/synthetase-OFF. The hydrolase and synthetase domains bear, remarkable similarities to the catalytic domains of the cyclic, phosphodiesterase and nucleotidyltransferase superfamilies, respectively., The active sites, separated by more than 30 A, contain bound nucleotides, including an unusual (p)ppGpp derivative, GDP-2':3'-cyclic monophosphate., Reciprocal regulation of the antagonistic catalytic activities, suggested, by the structure, is supported by mutagenesis experiments and appears to, involve ligand-induced signal transmission between the two active sites.

About this Structure

1VJ7 is a Single protein structure of sequence from Streptococcus dysgalactiae subsp. equisimilis with MN, GDP and GPX as ligands. Full crystallographic information is available from OCA.

Reference

Conformational antagonism between opposing active sites in a bifunctional RelA/SpoT homolog modulates (p)ppGpp metabolism during the stringent response [corrected]., Hogg T, Mechold U, Malke H, Cashel M, Hilgenfeld R, Cell. 2004 Apr 2;117(1):57-68. PMID:15066282

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