SecB, a molecular chaperone with two faces

Trends Microbiol. 2001 May;9(5):193-6. doi: 10.1016/s0966-842x(01)01980-1.


SecB is a molecular chaperone unique to the phylum Proteobacteria, which includes the majority of known Gram-negative bacteria of medical, industrial and agricultural significance. SecB is involved in the translocation of secretory proteins across the cytoplasmic membrane. The crystal structure of the Haemophilus influenzae SecB provides new insights into how SecB simultaneously recognizes its two ligands: unfolded preproteins and SecA, the ATPase subunit of the translocase. SecB uses its entire molecular surface for these two functions, but for preprotein release and its own membrane release, SecB relies on the catalytic activity of SecA. This defines SecB as a translocation-specific molecular chaperone.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism*
  • Binding Sites
  • Carrier Proteins / metabolism
  • Escherichia coli Proteins*
  • Haemophilus influenzae / chemistry*
  • Membrane Transport Proteins*
  • Models, Molecular
  • Molecular Chaperones / chemistry
  • Molecular Chaperones / metabolism*
  • Protein Binding
  • Protein Structure, Quaternary
  • SEC Translocation Channels
  • SecA Proteins


  • Bacterial Proteins
  • Carrier Proteins
  • Escherichia coli Proteins
  • Membrane Transport Proteins
  • Molecular Chaperones
  • SEC Translocation Channels
  • SecB protein, Bacteria
  • Adenosine Triphosphatases
  • SecA Proteins