1c4t
From Proteopedia
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CATALYTIC DOMAIN FROM TRIMERIC DIHYDROLIPOAMIDE SUCCINYLTRANSFERASE
Overview
The dihydrolipoamide succinyltransferase (E2o) component of the alpha-ketoglutarate dehydrogenase complex catalyzes the transfer of a succinyl group from the S-succinyldihydrolipoyl moiety to coenzyme A. E2o is normally a 24-mer, but is found as a trimer when E2o is expressed with a C-terminal [His]6 tag. The crystal structure of the trimeric form of the catalytic domain (CD) of the Escherichia coli E2o has been solved to 3.0 A resolution using the Molecular Replacement method. The refined model contains an intact trimer in the asymmetric unit and has an R-factor of 0.257 (Rfree = 0.286) for 18,699 reflections between 10.0 and 3.0 A resolution. The core of tE2oCD (residues 187-396) superimposes onto that of the cubic E2oCD with an RMS difference of 0.4 A for all main-chain atoms. The C-terminal end of tE2oCD (residues 397-404) rotates by an average of 37 degrees compared to cubic E2oCD, disrupting the normal twofold interface. Despite the alteration of quaternary structure, the active site of tE2oCD shows no significant differences from that of the cubic E2oCD, although several side chains in the active site are more ordered in the trimeric form of E2oCD. Analysis of the available sequence data suggests that the majority of E2 components have active sites that resemble that of E. coli E2oCD. The remaining E2 components can be divided into three groups based on active-site sequence similarity. Analysis of the surface properties of both crystal forms of E. coli E2oCD suggests key residues that may be involved in the protein-protein contacts that occur between the catalytic and lipoyl domains of E2o.
About this Structure
1C4T is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Dihydrolipoyllysine-residue succinyltransferase, with EC number 2.3.1.61 Full crystallographic information is available from OCA.
Reference
Expression, purification, and structural analysis of the trimeric form of the catalytic domain of the Escherichia coli dihydrolipoamide succinyltransferase., Knapp JE, Carroll D, Lawson JE, Ernst SR, Reed LJ, Hackert ML, Protein Sci. 2000 Jan;9(1):37-48. PMID:10739245
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