1n1d
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(New page: 200px<br /><applet load="1n1d" size="450" color="white" frame="true" align="right" spinBox="true" caption="1n1d, resolution 2.Å" /> '''Glycerol-3-phosphate c...)
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Revision as of 19:44, 20 November 2007
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Glycerol-3-phosphate cytidylyltransferase complexed with CDP-glycerol
Overview
The bacterial enzyme, glycerol-3-phosphate cytidylyltransferase (GCT), is, a model for mammalian cytidylyltransferases and is a member of a large, superfamily of nucleotidyltransferases. Dimeric GCT from Bacillus subtilis, displays unusual negative cooperativity in substrate binding and appears, to form products only when both active sites are occupied by substrates., Here we describe a complex of GCT with the product, CDP-glycerol, in a, crystal structure in which bound sulfate serves as a partial mimic of the, second product, pyrophosphate. Binding of sulfate to form a pseudo-ternary, complex is observed in three of the four chains constituting the, asymmetric unit and is accompanied by a backbone rearrangement at Asp11, and ordering of the C-terminal helix. Comparison with the CTP complex of, GCT, determined previously, reveals that in the product complex the active, site closes around the glycerol phosphate moiety with a concerted motion, of the segment 37-47 that includes helix B. This rearrangement allows, lysines 44 and 46 to interact with the glycerol and cytosine phosphates of, CDP-glycerol. Binding of CDP-glycerol also induces smaller movements of, residues 92-100. Roles of lysines 44 and 46 in catalysis have been, confirmed by mutagenesis of these residues to alanine, which decreases, Vmax(app) and has profound effects on the Km(app) for, glycerol-3-phosphate.
About this Structure
1N1D is a Single protein structure of sequence from Bacillus subtilis with SO4 and C2G as ligands. Active as Glycerol-3-phosphate cytidylyltransferase, with EC number 2.7.7.39 Full crystallographic information is available from OCA.
Reference
Glycerol-3-phosphate cytidylyltransferase. Structural changes induced by binding of CDP-glycerol and the role of lysine residues in catalysis., Pattridge KA, Weber CH, Friesen JA, Sanker S, Kent C, Ludwig ML, J Biol Chem. 2003 Dec 19;278(51):51863-71. Epub 2003 Sep 23. PMID:14506262
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