A mutation in the essential gene gmk (encoding guanlyate kinase) generates a requirement for adenine at low temperature in Salmonella enterica

J Bacteriol. 2003 Nov;185(22):6732-5. doi: 10.1128/JB.185.22.6732-6735.2003.


In Salmonella enterica serovar Typhimurium, gmk encodes guanylate kinase, an essential enzyme involved in the synthesis and salvage of guanine nucleotides. Here we report the isolation of a mutation in gmk that results in a nutritional requirement for adenine at low temperature. Comparisons of kinetic parameters from the wild-type and mutant Gmk enzymes revealed that the mutant enzyme had a more than 20-fold-higher Km for ATP than the wild-type enzyme. The growth dependence of the mutant on temperature and/or adenine could not be explained as a direct result of this kinetic difference. We propose a model in which previously described regulatory effects of GMP are responsible for these phenotypes.

Publication types

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

MeSH terms

  • Adenine / metabolism*
  • Cold Temperature*
  • Gene Expression Regulation, Bacterial*
  • Genes, Bacterial
  • Genes, Essential
  • Guanylate Kinases
  • Kinetics
  • Models, Biological
  • Molecular Sequence Data
  • Mutation*
  • Nucleoside-Phosphate Kinase / genetics*
  • Nucleoside-Phosphate Kinase / metabolism
  • Salmonella typhimurium / enzymology*
  • Salmonella typhimurium / genetics
  • Salmonella typhimurium / growth & development
  • Sequence Analysis, DNA


  • Nucleoside-Phosphate Kinase
  • Guanylate Kinases
  • Adenine

Associated data

  • GENBANK/AF140283