Characterization of the hlyB gene and its role in the production of the El Tor haemolysin of Vibrio cholerae O1

Mol Microbiol. 1990 Mar;4(3):413-25. doi: 10.1111/j.1365-2958.1990.tb00608.x.


El Tor strains of Vibrio cholerae are capable of producing a haemolysin which they actively secrete into the growth medium. This requires translation to produce the protein at the surface of the cytoplasmic membrane and translocation across this membrane, the periplasmic space and the outer membrane. The mechanism by which this occurs is poorly understood. In addition to the structural gene for the haemolysin (hlyA), we have cloned a second adjacent gene, hlyB. By site-directed mutagenesis, specific hlyB mutants have been constructed. These mutants are defective in the secretion of HlyA in the early to mid-exponential phase of growth and the haemolysin becomes trapped within the cell and is only released in stationary phase. Nucleotide sequence analysis and cell fractionations reveal HlyB to be a 60.3 kD putative outer membrane-associated protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Outer Membrane Proteins / genetics*
  • Bacterial Proteins*
  • Base Sequence
  • Carrier Proteins / genetics*
  • Cell Membrane / metabolism
  • DNA Transposable Elements
  • Genes, Bacterial*
  • Hemolysin Proteins / biosynthesis
  • Hemolysin Proteins / genetics*
  • Molecular Sequence Data
  • Mutation*
  • Protein Sorting Signals / genetics
  • Vibrio cholerae / genetics*
  • Vibrio cholerae / growth & development


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • DNA Transposable Elements
  • Hemolysin Proteins
  • Hlyb protein, Bacteria
  • Protein Sorting Signals

Associated data

  • GENBANK/X16945