title: Three-dimensional solution structure of the E3-binding domain of the dihydrolipoamide succinyltransferase core from the 2-oxoglutarate dehydrogenase multienzyme complex of Escherichia coli.
abstract: The three-dimensional solution structure of a 51-residue synthetic peptide comprising the dihydrolipoamide dehydrogenase (E3)-binding domain of the dihydrolipoamide succinyltransferase (E2) core of the 2-oxoglutarate dehydrogenase multienzyme complex of Escherichia coli has been determined by nuclear magnetic resonance spectroscopy and hybrid distance geometry-dynamical simulated annealing calculations. The structure is based on 630 approximate interproton distance and 101 torsion angle (phi, psi, chi 1) restraints. A total of 56 simulated annealing structures were calculated, and the atomic rms distribution about the mean coordinate positions for residues 12-48 of the synthetic peptide is 1.24 A for the backbone atoms, 1.68 A for all atoms, and 1.33 A for all atoms excluding the six side chains which are disordered at chi 1 and the seven which are disordered at chi 2; when the irregular partially disordered loop from residues 31 to 39 is excluded, the rms distribution drops to 0.77 A for the backbone atoms, 1.55 A for all atoms, and 0.89 A for ordered side chains. Although proton resonance assignments for the N-terminal 11 residues and the C-terminal 3 residues were obtained, these two segments of the polypeptide are disordered in solution as evidenced by the absence of nonsequential nuclear Overhauser effects. The solution structure of the E3-binding domain consists of two parallel helices (residues 14-23 and 40-48), a short extended strand (24-26), a five-residue helical-like turn, and an irregular (and more disordered) loop (residues 31-39). This report presents the first structure of an E3-binding domain from a 2-oxo acid dehydrogenase complex.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: M A
authors.initials: MA
authors.lastname: Robien
authors.forename: G M
authors.initials: GM
authors.lastname: Clore
authors.forename: J G
authors.initials: JG
authors.lastname: Omichinski
authors.forename: R N
authors.initials: RN
authors.lastname: Perham
authors.forename: E
authors.initials: E
authors.lastname: Appella
authors.forename: K
authors.initials: K
authors.lastname: Sakaguchi
authors.forename: A M
authors.initials: AM
authors.lastname: Gronenborn
mesh_terms: D000217:Acyltransferases / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008058:Dihydrolipoamide Dehydrogenase / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D007655:Ketoglutarate Dehydrogenase Complex / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011487:Protein Conformation; D012996:Solutions; D013816:Thermodynamics
chemical_list: D012996:Solutions; D007655:Ketoglutarate Dehydrogenase Complex; D008058:Dihydrolipoamide Dehydrogenase; D000217:Acyltransferases; C021515:dihydrolipoamide succinyltransferase