Potential genomic determinants of hyperthermophily.

We searched for genes that could be important for hyperthermophily using a flexible approach to phyletic pattern analysis. We identified 290 clusters of orthologous groups of proteins (COGs) that are preferentially present in archaeal and bacterial hyperthermophiles. Of these, 58 COGs include proteins from at least one bacterium and two archaea, and these were considered to be the best candidates for a specific association with the hyperthermophilic phenotype. Detailed sequence and genome-context analysis of these COGs led to functional predictions for several previously uncharacterized protein families, including a novel group of putative molecular chaperones and a unique transcriptional regulator.