Distribution of F- and A/V-type ATPases in Thermus scotoductus and other closely related species

Abstract

The presence of an A/V-type ATPase in different Thermus species and in the deeper branching species Meiothermus ruber and Deinococcus radiodurans suggests that the presence of the archaeal-type ATPase is a primitive character of the Deinococci that was acquired through horizontal gene transfer (HGT). However, the presence of a bacterial type F-ATPases was reported in two newly identified Thermus species ( Thermus scotoductus DSM 8553 and Thermus filiformis DSM 4687). Two different scenarios can explain this finding, either the recent replacement of the ancestral A/V-type ATPase in Thermus scotoductus and Thermus filiformis with a newly acquired F-type ATPase or a long-term persistence of both F and A type ATPase in the Deinococci, which would imply several independent losses of the F-type ATPase in the Deinococci. Using PCR with redundant primers, sequencing and Southern blot analyses, we tried to confirm the presence of an F-type ATPase in the genome of Thermus scotoductus and Thermus filiformis, and determine its phylogenetic affinities. Initial experiments appeared to confirm the presence of an F-type ATPase in Thermus scotoductus that was similar to the F-ATPases found in Bacillus. However, further experiments revealed that the detection of an F-ATPase was due to a culture contamination. For all the Thermus and Deinococcus species surveyed, including Thermus scotoductus, cultures that were free of contamination only contained an A/V-type ATP synthases.