Deamination of deoxycytidine nucleotides by the obligate intracytoplasmic bacterium Rickettsia prowazekii

J Bacteriol. 1991 Aug;173(15):4902-3. doi: 10.1128/jb.173.15.4902-4903.1991.


Thymidylate biosynthesis via the methylation of dUMP is required for DNA replication in Rickettsia prowazekii, an obligate intracytoplasmic bacterium. In theory, dUMP synthesis could occur either by the deamination of deoxycytidine nucleotides or by the reduction of uridine nucleotides. Accordingly, the incorporation of both radiolabeled cytidine and uridine into the thymidylate of R. prowazekii was examined. After DNA hydrolysis and high-performance liquid chromatography, it was determined that 85% of the rickettsial thymidylate was derived from cytidine and the remaining 15% was derived from uridine. These findings were supported by the identification of a dCTP deaminase activity in extracts of R. prowazekii. Extracts of R. prowazekii deaminated 1.7 +/- 0.3 nmol of dCTP/min/mg of protein (a value calculated to suffice for rickettsial growth), and no measurable activity was observed with dCMP as the substrate.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cytidine / metabolism
  • Cytidine Deaminase
  • Cytoplasm / microbiology*
  • Deoxycytosine Nucleotides / metabolism*
  • Nucleoside Deaminases / metabolism*
  • Rickettsia prowazekii / enzymology
  • Rickettsia prowazekii / genetics
  • Rickettsia prowazekii / metabolism*
  • Uridine / metabolism


  • Deoxycytosine Nucleotides
  • Cytidine
  • Nucleoside Deaminases
  • Cytidine Deaminase
  • deoxycytidine deaminase
  • Uridine