Identification of vancomycin resistance protein VanA as a D-alanine:D-alanine ligase of altered substrate specificity.
High-level glycopeptide resistance in Enterococcus faecium BM4147 is mediated by a 38-kDa protein VanA, whose amino acid sequence is related to Gram-negative D-alanine:D-alanine (D-Ala-D-Ala) ligases [Dutka-Malen, S., Molinas, C., Arthur, M., & Courvalin, P. (1990) Mol. Gen. Genet. 224, 364-372]. We report purification of VanA and demonstrate that it has D-Ala-D-Ala ligase activity but has substantially modified substrate specificity, compared with Gram-negative D-Ala-D-Ala ligases. VanA preferentially condenses D-Ala with D-Met or D-Phe, raising the possibility that its cellular role is to synthesize a modified cell-wall component, which is subsequently not recognized by vancomycin.
Bugg
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Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115.
Dutka-Malen
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S
Arthur
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Courvalin
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P
Walsh
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CT
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D019729:Carbon-Oxygen Ligases; D002850:Chromatography, Gel; D004352:Drug Resistance, Microbial / Q000502:physiology; D006090:Gram-Negative Bacteria / Q000201:enzymology; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013291:Streptococcus / Q000187:drug effects / Q000201:enzymology*; D013379:Substrate Specificity; D014640:Vancomycin / Q000494:pharmacology*
D001426:Bacterial Proteins; C071437:VanA ligase, Bacteria; D014640:Vancomycin; D019729:Carbon-Oxygen Ligases; D010453:Peptide Synthases; C019638:D-alanylalanine synthetase