Cyanobacterial hydrogenase specific endopeptidases. A) The hydrogenase specific endopeptidase genes (colored in yellow) and flanking regions are shown. The size of the flanking region was chosen so that all open reading frames having the same direction are included (putative operons; colored in gray). B) Annotation of the above genes according to genome database entries. In addition, the proposed annotation of the cyanobacterial hydrogenase maturating endopeptidases is shown.