Figure 1

Unrooted phylogenetic tree of hydrogenase specific proteases. The phylogenetic tree of hydrogenase specific proteases from the MrBayes analysis including the different subgroups they may be divided into. The proposed subgroups for each protease are marked in the figure; 1 (red), 2 (orange), 3a (blue), 3d (purple), 4 (green) and unknown (black). X: The point in the phylogenetic tree when horizontal gene transfer occurred. Y/Z: Suggested positions of root. B. The phylogenetic tree of hydrogenases adapted from Vignais et al 2004 [25]. Type 2a (HupL) and 3d (HoxH) hydrogenases which can be found in cyanobacteria are marked in bold. The phylogenetic tree was obtained using MrBayes analyses and the claude credibility values are given beside each branch. For abbreviations see Table 2.