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Research article2001Peer reviewedOpen access

Novel deoxynucleoside-phosphorylating enzymes in mycoplasmas: evidence for efficient utilization of deoxynucleosides

Wang, Liya; Westberg, Joakim; Bölske, Göran; Eriksson, Staffan

Abstract

Mycoplasmas are unable to synthesize purine and pyrimidine bases de novo. Therefore, salvage of existing nucleosides and bases is essential for their survival. Four mycoplasma species were studied with regard to their ability to phosphorylate deoxynucleosides. High levels of thymidine kinase (TK), deoxycytidine kinase (dCK), deoxyguanosine kinase (dGK) and deoxyadenosine kinase (dAK) activities were detected in extracts from Mycoplasma pneumoniae, Mycoplasma mycoides subsp. mycoides SC (M. mymySC), Acholeplasma laidlawii (A. laidlawii) and Mycoplasma arginini (M. arginini). Nucleoside phosphotransferase activities were found at high levels in A. laidlawii! and low levels in M. arginini. Pyrophosphate-dependent deoxynucleoside kinase activities were detected mainly in A. laidlawii and M. mymySC extracts. Two open reading frames were identified in the M. mymySC genome; one showed 25% sequence identity to human dGK and the other one had about 26% sequence identity to human TK1. The M. mymySC dGK-like enzyme was cloned, expressed in Escherichia coli and affinity-purified. This enzyme phosphorylated dAdo, dGuo and dCyd, and the highest catalytic rate was with dAdo as substrate. Therefore, we suggest that this enzyme should be named deoxyadenosine kinase. The physiological role of mycoplasma dAK and TK may be to support the unusually large dATP and dTTP pools required for replication of mycoplasma genomes.

Published in

Molecular Microbiology
2001, Volume: 42, number: 4, pages: 1065-1073

      SLU Authors

    • Wang, Liya

      • Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences

      • Eriksson, Staffan

        • Department of Veterinary Medical Chemistry, Swedish University of Agricultural Sciences

      UKÄ Subject classification

      Biochemistry and Molecular Biology
      Cell and Molecular Biology
      Microbiology in the medical area

      Publication identifier

      DOI: https://doi.org/10.1046/j.1365-2958.2001.02700.x

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/53113