COLD SHOCK STRESS-INDUCED PROTEINS IN BACILLUS-SUBTILIS

Bacteria respond to a decrease in temperature with the induction of pr oteins that are classified as cold-induced proteins (CIPs). Using two- dimensional gel electrophoresis, we analyzed the cold shock response i n Bacillus subtilis. After a shift from 37 to 15 degrees C, the synthe sis of a majority of proteins was repressed; in contrast, 37 proteins were synthesized at rates higher than preshift rates. One hour after c old shock, the induction of CIPs decreased, and after 2 h, general pro tein synthesis resumed. The identified main CIPs were excised from two -dimensional gels and were subjected to microsequencing. Three small a cidic proteins that showed the highest relative induction after cold s hock were highly homologous and belonged to a protein family of which one member, the major cold shock protein, CspB, has previously been ch aracterized. Two-dimensional gel analyses of a cspB null mutant reveal ed that CspB affects the level of induction of several CIPs. Other ide ntified CIPs function at various levels of cellular physiology, such a s chemotaxis (CheY), sugar uptake (Hpr), translation (ribosomal protei ns S6 and L7/L12), protein folding (PPiB), and general metabolism (Cys K, IlvC, Gap, and triosephosphate isomerase).