Consensus phylogenetic trees of Mch (A), Orf9 (B), Orf5 (C), and Orf7 (D) polypeptides. Bootstrap values are shown for distance, parsimony, and maximum-likelihood analyses. Nodes without bootstrap values are not strongly supported. M. extorquens, B. xenovorans, M. capsulatus, and M. flagellatus are Proteobacteria; G. obscuriglobus, Gemmata sp. strain Wa1-1, and R. baltica are Planctomycetes; M. thermoautotrophicus, M. kandleri, M. mazei, M. barkeri, M. acetivorans, A. fulgidus, and M. jannaschii are Archaea.