SPECIFIC AND GENERAL STRESS PROTEINS IN BACILLUS-SUBTILIS - A 2-DIMENSIONAL PROTEIN ELECTROPHORESIS STUDY

A computer-aided analysis of high resolution two-dimensional polyacryl amide gels was used to investigate the changes in the protein synthesi s profile in B. subtilis wild-type strains and sigB mutants in respons e to heat shock, salt and ethanol stress, and glucose or phosphate sta rvation. The data provided evidence that the induction of at least 42 general stress proteins absolutely required the alternative sigma fact or sigma(B). However, at least seven stress proteins, among them ClpC, ClpP, Sod, AhpC and AhpF, remained stress-inducible in a sigB mutant. Such a detailed analysis also permitted the description of subgroups of general stress proteins which are subject to additional regulatory circuits, indicating a very thorough fine-tuning of this complex respo nse. The relative synthesis rate of the general stress proteins consti tuted up to 40 % of the total protein synthesis of stressed cells and thereby emphasizes the importance of the stress regulon. Besides the i nduction of these general or rather unspecific stress proteins, the in duction of stress-specific proteins is shown and discussed.