1sq5
|
Crystal Structure of E. coli Pantothenate kinase
OverviewOverview
Pantothenate kinase catalyzes the first step in the biosynthesis of, coenzyme A, the major acyl group carrier in biology. In bacteria, regulation of pantothenate kinase activity is a major factor in, controlling intracellular coenzyme A levels, and pantothenate analogs are, growth-inhibiting antimetabolites. We have extended the structural, information on Escherichia coli pantothenate kinase by determining the, structure of the enzyme.ADP. pantothenate ternary complex. Pantothenate, binding induces a significant conformational change in amino acids, 243-263, which form a "lid" that folds over the open pantothenate binding, groove. The positioning of the substrates suggests the reaction proceeds, by a concerted mechanism that involves a dissociative transition state, although the negative charge neutralization of the gamma-phosphate by, Arg-243, Lys-101, and Mg(2+) coupled with hydrogen bonding of the C1 of, pantothenate to Asp-127 suggests different interpretations of the, phosphoryl transfer mechanism of pantothenate kinase., N-alkylpantothenamides are substrates for pantothenate kinase. Modeling, these antimetabolites into the pantothenate active site predicts that they, bind in the same orientation as pantothenate with their alkyl chains, interacting with the hydrophobic dome over the pantothenate pocket, which, is also accessed by the beta-mercaptoethylamine moiety of the allosteric, regulator, coenzyme A. These structural/biochemical studies illustrate the, intimate relationship between the substrate, allosteric regulator, and, antimetabolite binding sites on pantothenate kinase and provide a, framework for studies of its catalysis and feedback regulation.
About this StructureAbout this Structure
1SQ5 is a Single protein structure of sequence from Escherichia coli with PAU and ADP as ligands. Active as Pantothenate kinase, with EC number 2.7.1.33 Full crystallographic information is available from OCA.
ReferenceReference
The structure of the pantothenate kinase.ADP.pantothenate ternary complex reveals the relationship between the binding sites for substrate, allosteric regulator, and antimetabolites., Ivey RA, Zhang YM, Virga KG, Hevener K, Lee RE, Rock CO, Jackowski S, Park HW, J Biol Chem. 2004 Aug 20;279(34):35622-9. Epub 2004 May 10. PMID:15136582
Page seeded by OCA on Wed Nov 21 02:33:30 2007