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Evolved neomycin phosphotransferase from an isolate of Klebsiella pneumoniae
Article first published online: 27 OCT 2006
DOI: 10.1111/j.1365-2958.1991.tb00826.x
1365-2958/asset/cover.gif?v=1&s=75254d9e3ae6a0f08085f34cc6e5bd65d8e3d52e "Molecular Microbiology")
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How to Cite
Lee, K.-Y., Hopkins, J. D. and Syvanen, M. (1991), Evolved neomycin phosphotransferase from an isolate of Klebsiella pneumoniae. Molecular Microbiology, 5: 2039–2046. doi: 10.1111/j.1365-2958.1991.tb00826.x
Publication History
- Issue published online: 27 OCT 2006
- Article first published online: 27 OCT 2006
- Received 22 January, 1991; revised 13 May, 1991.
- Abstract
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Summary
A new aminoglycoside resistance gene (aphA 1-IA6) confers high-level resistance to neomycin. The sequence of apA 1-IAB is closely related to aphA 1 found in the transposons Tn4352, 7n903 and Tn602. For example, aphA 1-IAB differs from aphA 1–903 at five nucleotides that result in four amino acid replacements. The enzyme encoded by aphA 1-IAB has a significantly higher turnover number with neomycin, kanamycin and G418 as substrates than does the aphA 1–903 enzyme. A parsimonious phylogenetic tree suggests that aphA 1-IAB evolved from an ancestral form that is closely related or identical to the aphA 1 found in Tn903. The excess of replacement substitutions over silent substitutions in aphA I-IAB, as well as its convergence toward aphA 3 from Staphylococcus aureus, is indicative of selective evolution. Our hypothesis to explain these results is that aphA 1-IAB evolved under the selective pressure of neomycin use in relatively recent times.