The carboxyl terminus of the Bacillus subtilis SecA is dispensable for protein secretion and viability.
The Escherichia coli secretion-dedicated chaperone SecB targets a subset of proteins to the translocase by interacting with the carboxyl (C-) terminus of SecA. This region of SecA is highly conserved in Eubacteria, but despite its presence in the Bacillus subtilis SecA, the B. subtilis genome does not appear to contain a gene for a clear homologue of SecB. Deletion of the C-terminus of the B. subtilis SecA yields cells that have normal viability, but that exhibit a response reminiscent of oxidative stress and the loss of a number of secretory proteins from the culture supernatant. Semi-quantitative RT-PCR demonstrates that these proteins are expressed at lower levels. The C-terminus of SecA fused to glutathione S:-transferase (GST) specifically binds a cytosolic protein, termed MrgA. This protein has been reported to function in relation to oxidative stress, but deletion of the mrgA gene does not result in a secretion defect nor does it cause an oxidative stress response. It is concluded that the C-terminus of the B. subtilis SecA is not essential for secretion and viability.
van Wely
Karel H M
KHM
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands1.
Swaving
Jelto
J
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands1.
Klein
Michael
M
Institut für Biotechnologie 1, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany2.
Freudl
Roland
R
Institut für Biotechnologie 1, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany2.
Driessen
Arnold J M
AJM
Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands1.
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000254:growth & development* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D018384:Oxidative Stress / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins