1euc
CRYSTAL STRUCTURE OF DEPHOSPHORYLATED PIG HEART, GTP-SPECIFIC SUCCINYL-COA SYNTHETASE
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OverviewOverview
Succinyl-CoA synthetase (SCS) catalyzes the reversible, phosphorylation/dephosphorylation reaction: inverted question mark, inverted question mark inverted question markrm succinyl inverted, question markhbox inverted question mark- inverted question, markCoA+NDP+P_i inverted question markleftrightarrow succinate+CoA+NTP, inverted question mark inverted question markwhere N denotes adenosine or, guanosine. In the course of the reaction, an essential histidine residue, is transiently phosphorylated. We have crystallized and solved the, structure of the GTP-specific isoform of SCS from pig heart (EC 6.2.1.4), in both the dephosphorylated and phosphorylated forms. The structures were, refined to 2.1 A resolution. In the dephosphorylated structure, the enzyme, is stabilized via coordination of a phosphate ion by the active-site, histidine residue and the two "power" helices, one contributed by each, subunit of the alphabeta-dimer. Small changes in the conformations of, residues at the amino terminus of the power helix contributed by the, alpha-subunit allow the enzyme to accommodate either the covalently bound, phosphoryl group or the free phosphate ion. Structural comparisons are, made between the active sites in these two forms of the enzyme, both of, which can occur along the catalytic path. Comparisons are also made with, the structure of Escherichia coli SCS. The domain that has been shown to, bind ADP in E. coli SCS is more open in the pig heart, GTP-specific SCS, structure.
About this StructureAbout this Structure
1EUC is a Protein complex structure of sequences from Sus scrofa with PO4, SO4 and ZN as ligands. Active as Succinate--CoA ligase (GDP-forming), with EC number 6.2.1.4 Full crystallographic information is available from OCA.
ReferenceReference
Phosphorylated and dephosphorylated structures of pig heart, GTP-specific succinyl-CoA synthetase., Fraser ME, James MN, Bridger WA, Wolodko WT, J Mol Biol. 2000 Jun 23;299(5):1325-39. PMID:10873456
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