title: Separation of protein X from the dihydrolipoyl transacetylase component of the mammalian pyruvate dehydrogenase complex and function of protein X.
abstract: The dihydrolipoyl transacetylase (E2)-protein X-kinase subcomplex was resolved to produce an oligomeric transacetylase that was free of protein X and kinase subunits. We investigated the properties of this transacetylase E2 oligomer and of a form of the subcomplex from which only the lipoyl-bearing domain of protein X (XL) was removed. While retaining other catalytic and binding properties of the native subcomplex, the oligomeric transacetylase and the subcomplex lacking the XL domain had greatly reduced capacities both to support the overall reaction of the complex (upon reconstitution with other components) and to bind the dihydrolipoyl dehydrogenase component. Our results indicate that protein X, in part through its XL domain, contributes to the binding of the dihydrolipoyl dehydrogenase component and to the overall reaction of the complex.
authors.affiliation: Department of Biochemistry, Kansas State University, Manhattan 66506.
authors.forename: S L
authors.initials: SL
authors.lastname: Powers-Greenwood
authors.forename: M
authors.initials: M
authors.lastname: Rahmatullah
authors.forename: G A
authors.initials: GA
authors.lastname: Radke
authors.forename: T E
authors.initials: TE
authors.lastname: Roche
mesh_terms: D000123:Acetyltransferases / Q000032:analysis*; D000818:Animals; D002417:Cattle; D051047:Dihydrolipoyllysine-Residue Acetyltransferase; D066298:In Vitro Techniques; D008970:Molecular Weight; D011485:Protein Binding; D011768:Pyruvate Dehydrogenase Complex / Q000032:analysis / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D011768:Pyruvate Dehydrogenase Complex; D000123:Acetyltransferases; D051047:Dihydrolipoyllysine-Residue Acetyltransferase