2ibp | pdb_00002ibp
Crystal Structure of Citrate Synthase from Pyrobaculum aerophilum
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Overview
A growing number of organisms have been discovered inhabiting extreme, environments, including temperatures in excess of 100 degrees C. How, cellular proteins from such organisms retain their native folds under, extreme conditions is still not fully understood. Recent computational and, structural studies have identified disulfide bonding as an important, mechanism for stabilizing intracellular proteins in certain thermophilic, microbes. Here, we present the first proteomic analysis of intracellular, disulfide bonding in the hyperthermophilic archaeon Pyrobaculum, aerophilum. Our study reveals that the utilization of disulfide bonds, extends beyond individual proteins to include many protein-protein, complexes. We report the 1.6 A crystal structure of one such complex, a, citrate synthase homodimer. The structure contains two intramolecular, disulfide bonds, one per subunit, which result in the cyclization of each, protein chain in such a way that the two chains are topologically, interlinked, rendering them inseparable. This unusual feature emphasizes, the variety and sophistication of the molecular mechanisms that can be, achieved by evolution.
About this Structure
2IBP is a Single protein structure of sequence from Pyrobaculum aerophilum with ACT and MG as ligands. Active as Citrate (Si)-synthase, with EC number 2.3.3.1 Full crystallographic information is available from OCA.
Reference
Discovery of a thermophilic protein complex stabilized by topologically interlinked chains., Boutz DR, Cascio D, Whitelegge J, Perry LJ, Yeates TO, J Mol Biol. 2007 May 18;368(5):1332-44. Epub 2007 Mar 6. PMID:17395198
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