Gene cloning and characterization of VcrM, a Na+-coupled multidrug efflux pump, from Vibrio cholerae non-O1

Microbiol Immunol. 2003;47(6):419-27. doi: 10.1111/j.1348-0421.2003.tb03379.x.


We cloned a DNA fragment responsible for drug resistance from chromosome of Vibrio cholerae non-O1. Nucleotide sequence analysis of this fragment revealed the presence of a single open reading frame encoding a protein consisting of 445 amino acid residues. We designated the gene as vcrM. Hydropathy analysis of the deduced amino acid sequence of VcrM suggests the presence of 12 trans-membrane segments. A dendrogram showed that VcrM is a member of the DinF-subfamily within the MATE family of multidrug efflux pumps. Expression of the cloned vcrM gene in drug-hypersensitive Escherichia coli KAM32 cells made them resistant to acriflavine, 4', 6-diamidino-2-phenylindole, Hoechst 33342, rhodamine 6G, tetraphenylphosphonium chloride (TPPCl) and ethidium bromide. Efflux of acriflavine due to VcrM was dependent on Na+ or Li+. Moreover, Na+ efflux was observed with VcrM when TPPCl was added to Na+-loaded cells. Therefore, we conclude that VcrM is a Na+/drug antiporter-type multidrug efflux pump.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acriflavine / metabolism
  • Amino Acid Sequence
  • Anti-Bacterial Agents / metabolism
  • Anti-Bacterial Agents / pharmacology
  • Antiporters / genetics*
  • Antiporters / metabolism
  • Biological Transport
  • Cations, Monovalent / pharmacology
  • Cloning, Molecular
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Escherichia coli / drug effects
  • Escherichia coli / genetics
  • Genes, Bacterial*
  • Hydrophobic and Hydrophilic Interactions
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Multigene Family
  • Phylogeny
  • Recombinant Fusion Proteins / physiology
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Sodium / metabolism
  • Vibrio cholerae / drug effects
  • Vibrio cholerae / genetics*


  • Anti-Bacterial Agents
  • Antiporters
  • Cations, Monovalent
  • Recombinant Fusion Proteins
  • Acriflavine
  • Sodium

Associated data

  • GENBANK/AB073219