title: The ATP:Co(I)rrinoid adenosyltransferase (CobA) enzyme of Salmonella enterica requires the 2'-OH group of ATP for function and yields inorganic triphosphate as its reaction byproduct.
abstract: The specificity of the ATP:corrinoid adenosyltransferase (CobA) enzyme of Salmonella enterica serovar Typhimurium LT2 for its nucleotide substrate was tested using ATP analogs and alternative nucleotide donors. The enzyme showed broad specificity for the nucleotide base and required the 2'-OH group of the ribosyl moiety of ATP for activity. (31)P NMR spectroscopy was used to identify inorganic triphosphate (PPP(i)) as the byproduct of the reaction catalyzed by the CobA enzyme. Cleavage of triphosphate into pyrophosphate and orthophosphate did not occur, indicating that triphosphate cleavage was not required for release of the adenosylcorrinoid product. Triphosphate was a strong inhibitor of the reaction, with 85% of CobA activity lost when the ATP/PPP(i) ratio present in the reaction mixture was 1:2.5.
authors.affiliation: Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: Maris V
authors.initials: MV
authors.lastname: Fonseca
authors.forename: Nicole R
authors.initials: NR
authors.lastname: Buan
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Horswill
authors.forename: Ivan
authors.initials: I
authors.lastname: Rayment
authors.forename: Jorge C
authors.initials: JC
authors.lastname: Escalante-Semerena
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism / Q000502:physiology*; D019883:Alkyl and Aryl Transferases / Q000378:metabolism* / Q000502:physiology*; D001426:Bacterial Proteins; D001665:Binding Sites; D002384:Catalysis; D004305:Dose-Response Relationship, Drug; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D011485:Protein Binding; D019779:Salmonella enterica / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D000255:Adenosine Triphosphate; D019883:Alkyl and Aryl Transferases; C082269:ATP-corrinoid adenosyltransferase