A spontaneous point mutation in the aac(6')-Ib' gene results in altered substrate specificity of aminoglycoside 6'-N-acetyltransferase of a Pseudomonas fluorescens strain

FEMS Microbiol Lett. 1994 Jan 15;115(2-3):297-304. doi: 10.1111/j.1574-6968.1994.tb06654.x.


The aac(6')-Ib' gene from Pseudomonas fluorescens BM2687, encoding an aminoglycoside 6'-N-acetyltransferase type II which confers resistance to gentamicin but not to amikacin, was characterized. Nucleotide sequence determination indicated total identity between aac(6')-Ib' and the aac(6')-Ib gene from Pseudomonas aeruginosa BM2656 [1] with the exception of a C-to-T transition that results in a serine to leucine substitution at position 83 of the deduced polypeptide. The aac(6')-Ib gene specifies a type I enzyme which confers resistance to amikacin but not to gentamicin [2]. It thus appears that the point mutation detected is responsible for enzymic altered substrate specificity.

Publication types

  • Comparative Study

MeSH terms

  • Acetyltransferases / genetics*
  • Amikacin / pharmacology
  • Base Sequence
  • Cloning, Molecular
  • Drug Resistance, Microbial / genetics
  • Gene Amplification
  • Genes, Bacterial / genetics*
  • Gentamicins / pharmacology
  • Molecular Sequence Data
  • Point Mutation / genetics*
  • Pseudomonas fluorescens / genetics*
  • Sequence Analysis, DNA
  • Substrate Specificity / genetics


  • Gentamicins
  • Amikacin
  • Acetyltransferases
  • aminoglycoside N(6')-acetyltransferase

Associated data

  • GENBANK/L25666