Nucleotide sequence analysis of 2''-aminoglycoside nucleotidyl-transferase ANT(2'') from Tn4000: its relationship with AAD(3'') and impact on Tn21 evolution

Mol Microbiol. 1988 Nov;2(6):709-17. doi: 10.1111/j.1365-2958.1988.tb00081.x.


Aminoglycoside 2''-O-nucleotidyltransferase (AAD(2'')) mediates bacterial resistance to dibekacin, gentamicin, kanamycin, sisomicin and tobramycin. Its coding sequence, aadB, is part of Tn21-related transposon, Tn4000. Nucleotide sequence analysis revealed the presence of an open reading frame capable of specifying a protein of 177 amino acids with a calculated molecular weight of 21,240. The predicted amino acid sequence revealed up to 27% homology to that of three nucleotidyltransferases of type AAD(3''), which are widely distributed among Gram-negatives, and to the AAD(9) from Staphylococcus aureus transposon Tn554. The regions flanking aadB suggest that its insertion into Tn21 arose from a site-specific recombination event adjacent to the aadA gene.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Biological Evolution
  • DNA Transposable Elements*
  • DNA, Bacterial / genetics
  • Drug Resistance, Microbial / genetics
  • Escherichia coli / genetics
  • Genes, Bacterial
  • Gram-Negative Bacteria / genetics
  • Molecular Sequence Data
  • Nucleotidyltransferases / genetics*
  • Restriction Mapping


  • DNA Transposable Elements
  • DNA, Bacterial
  • Nucleotidyltransferases
  • gentamicin 2''-nucleotidyltransferase

Associated data

  • GENBANK/X12618