Stress induction of the Bacillus subtilis clpP gene encoding a homologue of the proteolytic component of the Clp protease and the involvement of ClpP and ClpX in stress tolerance

摘要: The Bacillus subtilis clpP gene, encoding the proteolytic component of Clp or Ti protease, was cloned and sequenced. amount clpP-specific mRNA increased after heat shock, salt ethanol stress, as well treatment with puromycin. Two transcriptional start sites upstream structural gene were identified, preceded by sequences resembling consensus promoters recognized σA andσB factors B. RNA polymerase respectively. Transcription initiation occurred predominantly at putative σA-dependent promoter in exponentially growing cells induced under stress conditions. After exposure to transcription also σB-dependent promoter, but a lesser extent, indicating that belongs double promoter-controlled subgroup class III general genes subtilis. In sigB mutant strain, remained inducible promoter. BgaB–reporter fusions, carrying either σA- showed higher bgaB induction whereas significantly lower level measured appeared be crucial for heat-inducible clpP. A CIRCE (controlling inverted repeat chaperone expression) element, characteristic regulation target I shock such dnaK groESL, not found between translational sites. Mutants lacking ClpP regulatory ATPase ClpX phenotypically distinct from wild type. Both mutants produced chains elongated exhibited severely impaired growth conditions starvation. Comparison two-dimensional protein gels wild-type those clpX revealed several changes pattern. Several proteins, GroEL, PpiB, PykA, SucD, YhfP, YqkF, YugJ YvyD, which preferentially amounts both mutants, might potential substrates ClpXP protease.