The rapid degradation of mutant SecA protein in the Bacillus subtilis secA341 (ts) mutant causes a protein translocation defect in the cell.
To study the function of SecA protein and the protein translocation system of Bacillus subtilis, wild-type and mutant SecA proteins were characterized in vivo and in vitro. SecA protein was abundant in a wild-type strain (168) and existed in a stable homodimer. In contrast to this, SecA341 (ts) protein having an amino acid replacement from proline to leucine at residue 431 was undetectable by immunoblotting in the cell lysate of a secA341 mutant (TB301) at the nonpermissive temperature, 42 degrees C. Pulse-chase studies using 35S-methionine showed that newly synthesized SecA protein was rapidly degraded in the mutant at 42 degrees C. Purified SecA341 protein was more sensitive to trypsin and subtilisin than purified wild-type SecA protein in the presence of ATP. These results indicate that the secA341 mutation causes the rapid degradation of mutant SecA protein and a concomitant protein translocation defect in the cell.
Takamatsu
H
H
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Nakane
A
A
Sadaie
Y
Y
Nakamura
K
K
Yamane
K
K
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D001692:Biological Transport / Q000502:physiology; D002850:Chromatography, Gel; D010450:Endopeptidases / Q000378:metabolism; D029968:Escherichia coli Proteins; D006868:Hydrolysis; D015151:Immunoblotting; D026901:Membrane Transport Proteins; D009154:Mutation; D010957:Plasmids; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D014178:Translocation, Genetic; D014357:Trypsin / Q000378:metabolism; D001618:beta-Lactamases / Q000096:biosynthesis
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; D010450:Endopeptidases; D014357:Trypsin; D001618:beta-Lactamases; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins