1kc7
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(New page: 200px<br /><applet load="1kc7" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kc7, resolution 2.2Å" /> '''Pyruvate Phosphate Di...)
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Revision as of 16:55, 20 November 2007
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Pyruvate Phosphate Dikinase with Bound Mg-phosphonopyruvate
Overview
Crystals of pyruvate phosphate dikinase in complex with a substrate, analogue inhibitor, phosphonopyruvate (K(i) = 3 microM), have been, obtained in the presence of Mg(2+). The structure has been determined and, refined at 2.2 A resolution, revealing that the Mg(2+)-bound, phosphonopyruvate binds in the alpha/beta-barrel's central channel, at the, C-termini of the beta-strands. The mode of binding resembles closely the, previously proposed PEP substrate binding mode, inferred by the homology, of the structure (but not sequence homology) to pyruvate kinase. Kinetic, analysis of site-directed mutants, probing residues involved in inhibitor, binding, showed that all mutations resulted in inactivation, confirming, the key role that these residues play in catalysis. Comparison between the, structure of the PPDK-phosphonopyruvate complex and the structures of two, complexes of pyruvate kinase, one with Mg(2+)-bound phospholactate and the, other with Mg(2+)-oxalate and ATP, revealed that the two enzymes share, some key features that facilitate common modes of substrate binding. There, are also important structural differences; most notably, the machinery for, acid/base catalysis is different.
About this Structure
1KC7 is a Single protein structure of sequence from Clostridium symbiosum with MG, SO4 and PPR as ligands. Active as Pyruvate, phosphate dikinase, with EC number 2.7.9.1 Full crystallographic information is available from OCA.
Reference
Pyruvate site of pyruvate phosphate dikinase: crystal structure of the enzyme-phosphonopyruvate complex, and mutant analysis., Herzberg O, Chen CC, Liu S, Tempczyk A, Howard A, Wei M, Ye D, Dunaway-Mariano D, Biochemistry. 2002 Jan 22;41(3):780-7. PMID:11790099
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