title: Assignment of function to histidines 260 and 298 by engineering the E1 component of the Escherichia coli 2-oxoglutarate dehydrogenase complex; substitutions that lead to acceptance of substrates lacking the 5-carboxyl group.
abstract: The first component (E1o) of the Escherichia coli 2-oxoglutarate dehydrogenase complex (OGDHc) was engineered to accept substrates lacking the 5-carboxylate group by subjecting H260 and H298 to saturation mutagenesis. Apparently, H260 is required for substrate recognition, but H298 could be replaced with hydrophobic residues of similar molecular volume. To interrogate whether the second component would allow synthesis of acyl-coenzyme A derivatives, hybrid complexes consisting of recombinant components of OGDHc (o) and pyruvate dehydrogenase (p) enzymes were constructed, suggesting that a different component is the "gatekeeper" for specificity for these two multienzyme complexes in bacteria, E1p for pyruvate but E2o for 2-oxoglutarate.
authors.affiliation: Department of Chemistry and Environmental Science, New Jersey Institute of Technology, University Heights, Newark, New Jersey 07102, United States.
authors.forename: Da Jeong
authors.initials: da J
authors.lastname: Shim
authors.forename: Natalia S
authors.initials: NS
authors.lastname: Nemeria
authors.forename: Anand
authors.initials: A
authors.lastname: Balakrishnan
authors.forename: Hetalben
authors.initials: H
authors.lastname: Patel
authors.forename: Jaeyoung
authors.initials: J
authors.lastname: Song
authors.forename: Junjie
authors.initials: J
authors.lastname: Wang
authors.forename: Frank
authors.initials: F
authors.lastname: Jordan
authors.forename: Edgardo T
authors.initials: ET
authors.lastname: Farinas
mesh_terms: D000595:Amino Acid Sequence; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006639:Histidine / Q000502:physiology*; D007655:Ketoglutarate Dehydrogenase Complex / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D015202:Protein Engineering / Q000379:methods*; D013379:Substrate Specificity / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D006639:Histidine; D007655:Ketoglutarate Dehydrogenase Complex