Figure 6

Sequence alignment and representative domain architectures of novel HNH nuclease families: (A) Tox-HHH, (B) Tox-EHHH, (C) Tox-SHH, (D) Tox-GHH2, and (E) Tox-GHH. ‘#’ indicates residues involved in metal ion-binding, ‘%’ indicates the conserved histidine which is required for activation of the water molecule for hydrolysis, and ‘*’ indicates polar residues (often asparagine) that are conserved in the HNH fold. The labeling scheme for domain architectures and alignments, and the coloring scheme and consensus abbreviations are as in  3.