ACQUIRED THERMOTOLERANCE AND TEMPERATURE-INDUCED PROTEIN ACCUMULATIONIN THE EXTREMELY THERMOPHILIC BACTERIUM RHODOTHERMUS-OBAMENSIS

Temperature-induced changes in thermotolerance and protein composition were examined in heat-shocked cells and high-temperature-grown cells of the extremely thermophilic bacterium Rhodothermus obamensis. The su rvival at temperatures superoptimal for growth (90 and 95 degrees C) w as enhanced in both heat-shocked cells and high-temperature-grown cell s relative to that of cells groan at optimal temperatures. In a compar ison of protein composition using two-dimensional gel electrophoresis, putative heat shock proteins (HSPs) and high-temperature growth-speci fic proteins (HGPs) were detected. N-terminal amino acid sequence anal ysis revealed that the putative HSPs mere quite similar to the ATP-bin ding subunits of ABC transporters rabid the HGPs were proteins corresp onding to domains II and III of elongation factor Tu. These results su ggested that this extreme thermophile has developed temperature-induce d responses that include increased survival under hyperthermal conditi ons, changes in protein composition, and also the production of novel HSPs.