1kof

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Revision as of 17:22, 20 November 2007

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spinqualitylabelsall models 1kof, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of gluconate kinase

Overview

The crystal structure of gluconate kinase from Escherichia coli has been, determined to 2.0 A resolution by X-ray crystallography. The, three-dimensional structure was solved by multi-wavelength anomalous, dispersion, using a crystal of selenomethionine-substituted enzyme., Gluconate kinase is an alpha/beta structure consisting of a twisted, parallel beta-sheet surrounded by alpha-helices with overall topology, similar to nucleoside monophosphate (NMP) kinases, such as adenylate, kinase. In order to identify residues involved in substrate binding and, catalysis, structures of binary complexes with ATP, the ATP analogue, adenosine 5'-(beta,gamma-methylene) triphosphate and the product, gluconate-6-phosphate have been determined. Significant conformational, changes are induced upon binding of ATP to the enzyme. The largest changes, involve a hinge-bending motion of the NMP(bind) part and a motion of the, LID with adjacent helices, which opens the cavity to the second substrate, gluconate. Opening of the active site cleft upon ATP binding is the, opposite of what has been observed in the NMP kinase family so far, which, usually close their active site to prevent fortuitous hydrolysis of ATP., The conformational change positions the side-chain of Arg120 to stack with, the purine ring of ATP and the side-chain of Arg124 is shifted to interact, with the alpha-phosphate in ATP, at the same time protecting ATP from, solvent water. The beta and gamma-phosphate groups of ATP bind in the, predicted P-loop. A conserved lysine side-chain interacts with the, gamma-phosphate group, and might promote phosphoryl transfer., Gluconate-6-phosphate binds with its phosphate group in a similar position, as the gamma-phosphate of ATP, consistent with inline phosphoryl transfer., The gluconate binding-pocket in GntK is located in a different position, than the nucleoside binding-site usually found in NMP kinases.

About this Structure

1KOF is a Single protein structure of sequence from Escherichia coli with MG and ACP as ligands. Active as Gluconokinase, with EC number 2.7.1.12 Full crystallographic information is available from OCA.

Reference

Conformational changes during the catalytic cycle of gluconate kinase as revealed by X-ray crystallography., Kraft L, Sprenger GA, Lindqvist Y, J Mol Biol. 2002 May 10;318(4):1057-69. PMID:12054802

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