Structure and function of haemolysin B,P-glycoprotein and other members of a novel family of membrane translocators

Mol Microbiol. 1990 Jun;4(6):873-80. doi: 10.1111/j.1365-2958.1990.tb00660.x.


Recent studies have identified two sub-families of highly conserved polypeptides in a wide variety of organisms concerned with the transport of many different compounds, specific for each transport protein. Both families, represented by HisP and HlyB, respectively, have in common a highly conserved, approximately 25 kD domain, containing an ATP-binding site. The HisP sub-family essentially consists of cytoplasmic proteins which couple energy to the import of small substrates through cytoplasmic membrane permeases in Gram-negative bacteria. The HlyB (P-glycoprotein) sub-family, on the other hand, contains a second large domain which apparently acts as the transmembrane translocator itself, which in most cases drives the secretion of a variety of compounds. These membrane domains share a number of structural features which also serve to distinguish these proteins as a closely related group. Nevertheless, the compounds secreted by the HlyB sub-family include large polypeptides, polysaccharides and a variety of anti-tumour drugs. We describe here the properties of each of these remarkable proteins and we speculate on their possible mechanism of action.

Publication types

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

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Amino Acid Sequence
  • Animals
  • Bacteria / metabolism
  • Bacterial Outer Membrane Proteins / metabolism*
  • Bacterial Proteins*
  • Biological Transport
  • Carrier Proteins / metabolism*
  • Cell Membrane / metabolism
  • Hemolysin Proteins / metabolism*
  • Humans
  • Membrane Glycoproteins / metabolism*
  • Molecular Sequence Data
  • Structure-Activity Relationship


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • Hemolysin Proteins
  • Hlyb protein, Bacteria
  • Membrane Glycoproteins