Hyperthermus butylicus DSM 5456

Hyperthermus butylicus (strain DSM 5456 / JCM 9403) is an extreme hyperthermophilic, anaerobic, sulfur-reducing archeon phylogenetically associated with the kingdom Crenarchaeota. This organism was isolated from the sea floor of a solfataric (volcanic area that gives off gas) environment with temperatures up to 112 degrees Celsius at a depth of 9 meter, off the shore of Sao Miguel Island, Azores. Hyperthermus butylicus grows optimally at 95-106 degrees Celsius, with a NaCl concentration of 17 g/l and a pH of 7.0. It utilizes peptide mixtures as carbon and energy sources but not amino acid mixtures, various synthetic peptides or undigested protein. It can also generate energy by reduction of elemental sulfur to yield hydrogen sulfide. Fermentation products include carbon dioxide, 1-butanol, acetic acid, phenylacetic acid and a trace of hydroxyphenyl acetic acid, which are produced in the presence or absence of sulfur and hydrogen. Its genome consists of a single circular chromosome of 1,667,163 bp with a 53.7% G+C content. A total of 1672 genes were annotated, of which 1602 are protein-coding, and up to a third are specific to H. butylicus. A large percentage of the predicted start codons are GUG (25%) or UUG (37%). Many of the predicted metabolic gene products are associated with the fermentation of peptide mixtures including several peptidases with diverse specificities, and there are many encoded transporters. Most of the sulfur-reducing enzymes, hydrogenases and electron-transfer proteins were identified which are associated with energy production by reducing sulfur to hydrogen sulfide. Two large clusters of regularly interspaced repeats (CRISPRs) are present, one of which is associated with a crenarchaeal-type cas gene superoperon; none of the spacer sequences yielded good sequence matches with known archaeal chromosomal elements. Two cdc6 genes are present, but neither could be linked unambiguously to an origin of replication. The genome carries no detectable transposable or integrated elements, no inteins, and introns are exclusive to tRNA genes. This suggests that the genome structure is quite stable, possibly reflecting a constant, and relatively uncompetitive, natural environment. (HAMAP: HYPBU)