1scu
From Proteopedia
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THE CRYSTAL STRUCTURE OF SUCCINYL-COA SYNTHETASE FROM ESCHERICHIA COLI AT 2.5 ANGSTROMS RESOLUTION
Overview
The x-ray crystal structure of succinyl-CoA synthetase (SCS) from, Escherichia coli has been determined by the method of multiple isomorphous, replacement to a resolution of 2.5 A. Crystals of SCS are tetragonal with, a space group of P4(3)22 and unit cell dimensions of a = b = 98.47 A and c, = 400.6 A. One molecule of SCS (142 kDa) is contained in the asymmetric, unit. The current model has been refined to a conventional R factor of, 21.6% with root mean square deviations from ideal stereochemistry of 0.022, A for bond lengths and 3.25 degrees for bond angles. The quaternary, organization of the E. coli enzyme is an alpha 2 beta 2 heterotetramer. In, this tetramer, the alpha-subunits interact only with the beta-subunits, whereas the beta-subunits interact to form the dimer of alpha beta-dimers., The two active site pockets are located at regions of contact between, alpha- and beta-subunits. One molecule of coenzyme A is bound to each, alpha-subunit at a typical nucleotide-binding motif, and His-246 of each, alpha-subunit is phosphorylated. This phosphohistidine, a catalytic, intermediate, is stabilized by two helix dipoles (the "power" helices), one from each of the two subunit types. A short segment of the, beta-subunit from one alpha beta-dimer is in close proximity to the, CoA-binding site of the other alpha beta-dimer, providing a possible, rationale for the overall tetrameric structure.
About this Structure
1SCU is a Protein complex structure of sequences from Escherichia coli with COA and PHS as ligands. Active as Succinate--CoA ligase (ADP-forming), with EC number 6.2.1.5 Full crystallographic information is available from OCA.
Reference
The crystal structure of succinyl-CoA synthetase from Escherichia coli at 2.5-A resolution., Wolodko WT, Fraser ME, James MN, Bridger WA, J Biol Chem. 1994 Apr 8;269(14):10883-90. PMID:8144675
Page seeded by OCA on Wed Nov 21 02:17:00 2007
