%0 Journal Article
%T A Deeply Branching Thermophilic Bacterium with an Ancient Acetyl-CoA Pathway Dominates a Subsurface Ecosystem
%A Hideto Takami
%A Hideki Noguchi
%A Yoshihiro Takaki
%A Ikuo Uchiyama
%A Atsushi Toyoda
%A Shinro Nishi
%A Gab-Joo Chee
%A Wataru Arai
%A Takuro Nunoura
%A Takehiko Itoh
%A Masahira Hattori
%A Ken Takai
%J PLOS ONE
%D 2012
%I Public Library of Science (PLoS)
%R 10.1371/journal.pone.0030559
%X A nearly complete genome sequence of Candidatus ¡®Acetothermum autotrophicum¡¯, a presently uncultivated bacterium in candidate division OP1, was revealed by metagenomic analysis of a subsurface thermophilic microbial mat community. Phylogenetic analysis based on the concatenated sequences of proteins common among 367 prokaryotes suggests that Ca. ¡®A. autotrophicum¡¯ is one of the earliest diverging bacterial lineages. It possesses a folate-dependent Wood-Ljungdahl (acetyl-CoA) pathway of CO2 fixation, is predicted to have an acetogenic lifestyle, and possesses the newly discovered archaeal-autotrophic type of bifunctional fructose 1,6-bisphosphate aldolase/phosphatase. A phylogenetic analysis of the core gene cluster of the acethyl-CoA pathway, shared by acetogens, methanogens, some sulfur- and iron-reducers and dechlorinators, supports the hypothesis that the core gene cluster of Ca. ¡®A. autotrophicum¡¯ is a particularly ancient bacterial pathway. The habitat, physiology and phylogenetic position of Ca. ¡®A. autotrophicum¡¯ support the view that the first bacterial and archaeal lineages were H2-dependent acetogens and methanogenes living in hydrothermal environments.
%U http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0030559