P. Laksanalamai et al., Regulation and mechanism of action of the small heat shock protein from the hyperthermophilic archaeon Pyrococcus furiosus, J BACT, 183(17), 2001, pp. 5198-5202
The small heat shock protein (sHSP) from the hyperthermophile Pyrococcus fu
riosus was specifically induced at the level of transcription by heat shock
at 105 degreesC. The gene encoding this protein was cloned and overexpress
ed in Escherichia coli. The recombinant sHSP prevented the majority of E. c
oli proteins from aggregating in vitro for up to 40 min at 105 degreesC. Th
e sHSP also prevented bovine glutamate dehydrogenase from aggregating at 56
degreesC. Survivability of E. coli overexpressing the sHSP was enhanced ap
proximately sixfold during exposure to 50 degreesC for 2 h compared with th
e control culture, which did not express the sHSP. Apparently, the sHSP con
fers a survival advantage on mesophilic bacteria by preventing protein aggr
egation at supraoptimal temperatures.