Conserved amino acid sequence blocks in the multiple sequence alignment of M.NruI and M.Sbo13I family sequences. The homologous sequences found in GenBank are: gi_148658155 (YP_001278360), gi_149918461 (ZP_01906951), gi_225022629 (ZP_03711821), gi_252123721 (ZP_04834998) and putative methyltransferase M.Rca13941_ORF2728P. The consensus amino acid residues are indicated below the 7 actual sequences. The h and e indicate secondary structural prediction for α-helix (indicated in red) and β-strand (indicated in blue) respectively. Conserved amino acid motifs (blocks) I through X are shown above the amino acid sequences.