Crenarchaeon sequence

Pyrobaculum aerophilum is a hyperthermophilic crenachaeon that cannot tolerate the presence of elemental sulfur. In the January 22 issue of Proceedings of the National Academy of Sciences, Sorel Fitz-Gibbon report the complete genome sequence of the P. aerophilum IM2 strain that was isolated from a boiling marine water hole in Maronti Beach, Italy (Proc Natl Acad Sci USA 2002, 99:984-989).

The genome is 2.2 Mb long, has a 51% G+C content, and contains 2,587 predicted proteins. Fitz-Gibbon et al. found examples of instability of mononucleotide runs and failed to find evidence for a mismatch repair system, suggesting a 'mutator phenotype'. P. aerophilum lacks 5' untranslated regions suggesting an unusual mechanism for translation initiation. The genome contains enzymes for the glyoxylate cycle, 2-oxoacid dehydrogenase multienzyme complexes, and glycolysis.

The P. aerophilum genome has inactivated adenylsulfate reductase genes, explaining its sulfur intolerance and offering a means for developing a...