A hot story from comparative genomics: reverse gyrase is the only hyperthermophile-specific protein

I have looked for proteins that are present in all hyperthermophile genomes, but absent from all mesophile or thermophile genomes by using the phylogenetic pattern search program of the COG database. Surprisingly, this search retrieved only one such hyperthermophile-specific protein: reverse gyrase. This result emphasizes the importance of reverse gyrase in the adaptation of life to very high temperatures, and strengthens the idea that evolution of this enzyme was crucial in the origin of hyperthermophiles.