The rapid degradation of mutant secA protein in the Bacillus subtilis secA341 (ts) mutant causes a protein translocation defect in the cell

• Published in: Bioscience, biotechnology, and biochemistry Vol. 58; no. 10; pp. 1845 - 1850
• Main Authors: Takamatsu, H. (Tsukuba Univ., Ibaraki (Japan)), Nakane, A, Sadaie, Y, Nakamura, K, Yamane, K
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society for Bioscience Biotechnology and Agrochemistry 01.10.1994; Oxford University Press
• Subjects: Adenosine Triphosphatases - chemistry; Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - metabolism; BACILLUS SUBTILIS; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; beta-Lactamases - biosynthesis; Biological and medical sciences; Biological Transport - physiology; Biotechnology; CALOR; CHALEUR; Chromatography, Gel; DEFAUT; DEFECTOS; DEFECTS; DEGRADACION; DEGRADATION; Endopeptidases - metabolism; ESCHERICHIA; Escherichia coli Proteins; Fundamental and applied biological sciences. Psychology; Genetics; HEAT; Hydrolysis; Immunoblotting; Membrane Transport Proteins; Microbiology; MUTANT; MUTANTES; MUTANTS; Mutation; PLASMIDE; PLASMIDIOS; PLASMIDS; PROTEINAS; PROTEINE; PROTEINS; RESISTANCE A LA TEMPERATURE; RESISTENCIA A LA TEMPERATURA; SEC Translocation Channels; SECRECION; SECRETION; TEMPERATURE RESISTANCE; Translocation, Genetic; Trypsin - metabolism; Structure stability; Bacillales; Bacillus subtilis; Gene product; Enzymatic digestion; Bacteria; Dimer; Mutation; Bacillaceae; Membrane translocation
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.58.1845

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.