Figure 1.

Multiple sequence alignment of 25 members of the R.Hpy188I family, together with the structurally characterized homologs from the GIY-YIG superfamily, UvrC (1yd0) and I-TevI (1mk0). The members are indicated by the NCBI GI number followed by the original REBASE name, e.g. R.Hpy188I (for sequences available in REBASE, e.g. R.Hpy188I) or the abbreviated genus and species name with exception of Marine for the marine metagenome and Synpha for Synechococcus phage S-PM2. Amino acid residues are colored according to the similarity of their physico-chemical properties. Secondary structure (ss), as determined experimentally for UvrC and I-TevI and predicted for R.Hpy188I (taken from the final model presented in the present study), is indicated below the alignment as tubes (helices) and arrows (strands). The alternative positions of Arg residue (84 or 104 or 105 in R.Hpy188I sequence) are indicated by asterisks (*) above the alignment, whereas the position of the two Cys residues C90 and C101 is indicated by plus characters (+).