Binding of cob(II)alamin to the adenosylcobalamin-dependent ribonucleotide reductase from Lactobacillus leichmannii: Identification of dimethylbenzimidazole as the axial ligand

Christopher C. Lawrence, Gary J. Gerfen, Vicente Samano, Rainer Nitsche, Morris J. Robins, János Rétey, Jo Anne Stubbe

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

The ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii catalyzes the reduction of nucleoside 5'-triphosphates to 2'- deoxynucleoside 5'-triphosphates and uses coenzyme B12, adenosylcobalamin (AdoCbl), as a cofactor. Use of a mechanism-based inhibitor, 2'-deoxy-2'- methylenecytidine 5'-triphosphate, and isotopically labeled RTPR and AdoCbl in conjunction with EPR spectroscopy has allowed identification of the lower axial ligand of cob(II)alamin when bound to RTPR. In common with the AdoCbl- dependent enzymes catalyzing irreversible heteroatom migrations and in contrast to the enzymes catalyzing reversible carbon skeleton rearrangements, the dimethylbenzimidazole moiety of the cofactor is not displaced by a protein histidine upon binding to RTPR.

Original languageEnglish (US)
Pages (from-to)7039-7042
Number of pages4
JournalJournal of Biological Chemistry
Volume274
Issue number11
DOIs
Publication statusPublished - Mar 12 1999

    Fingerprint

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this