Nucleotide sequence of a novel kanamycin resistance gene, aphA-7, from Campylobacter jejuni and comparison to other kanamycin phosphotransferase genes

Plasmid. 1989 Jul;22(1):52-8. doi: 10.1016/0147-619x(89)90035-8.


A novel kanamycin phosphotransferase gene, aphA-7, was cloned from a 14-kb plasmid obtained from a strain of Campylobacter jejuni and the nucleotide sequence of the gene was determined. The presumed open reading frame of the aphA-7 structural gene was 753 bp in length and encoded a protein of 251 amino acids with a calculated weight of 29,691 Da. A 29-kDa protein was demonstrated in Escherichia coli maxicells containing the cloned aphA-7 gene. A ribosomal binding site corresponding to 5 of 8 bases of the 3' end of the E. coli 16S rRNA was 8 bp upstream of the start codon. Sequences corresponding to the -35 and -10 regions of the consensus promoter sequences of E. coli were upstream of the presumed initiation codon of the gene. The DNA sequence was most closely related to the aphA-3 gene from Streptococcus faecalis, showing 55.4% sequence similarity. There was 45.6% identity at the amino acid level between the aphA-3 and the aphA-7 proteins. Of the three conserved regions noted previously in phosphotransferase genes, the aphA-7 amino acid sequence was identical to the six conserved amino acids in motif 3, but differed in one of the five conserved amino acids in motif 1 (if gaps are permitted) and 3 of the 10 conserved residues in motif 2. The 32.8% G + C ratio in the open reading frame of the aphA-7 kanamycin resistance gene, which is similar to that of the C. jejuni chromosome, suggests that the aphA-7 may be indigenous to Campylobacters.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Aminoglycosides / pharmacology
  • Base Sequence
  • Campylobacter fetus / drug effects
  • Campylobacter fetus / enzymology
  • Campylobacter fetus / genetics*
  • Chimera
  • Cloning, Molecular
  • DNA, Bacterial / genetics
  • Drug Resistance, Microbial
  • Electrophoresis, Polyacrylamide Gel
  • Genes, Bacterial*
  • Kanamycin / genetics*
  • Kanamycin Resistance / genetics*
  • Molecular Sequence Data
  • Phosphotransferases / genetics*
  • Plasmids
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid


  • Aminoglycosides
  • DNA, Bacterial
  • Kanamycin
  • Phosphotransferases

Associated data

  • GENBANK/J03316
  • GENBANK/M29953