The chaperones of the archaeon Thermoplasma acidophilum

Chaperones are an essential component of a cell's ability to respond to env ironmental challenges. Chaperones have been studied primarily in bacteria, but in recent years it has become apparent that some classes of chaperones either are very divergent in bacteria relative to archaea and eukaryotes or are missing entirely. In contrast, a high degree of similarity was found b etween the chaperonins of archaea and those of the eukaryotic cytosol, whic h has led to the establishment of archaeal model systems. The archaeon most extensively used for such studies is Thermoplasma acidophilum, which thriv es at 59 degreesC and pH 2. Here we review information on its chaperone com plement in light of the recently determined genome sequence. (C) 2001 Acade mic Press.