SecB, a molecular chaperone with two faces.
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.
Driessen
A J
AJ
Dept of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, Groningen, The Netherlands. a.j.m.driessen@biol.rug.nl
D000251:Adenosine Triphosphatases / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D029968:Escherichia coli Proteins; D006193:Haemophilus influenzae / Q000737:chemistry*; D026901:Membrane Transport Proteins; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; D000069816:SEC Translocation Channels; C057842:SecB protein, Bacteria; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins