Alignment of the proteins deduced from the nucleotide sequences of IS1631, IS21, and IS1162. Heavy shading indicates identical amino acid residues in all elements; light shading denotes similar or partially conserved residues. Residues within the following groups were considered similar: G, A, S, T, and P; L, I, V, and M; F, Y, and W; D, E, N, and Q; and K, R, and H. (A) IS1631 ORF1 protein and related proteins. ∗, DDE motif. (B) IS1631 ORF2 protein and related proteins. ATP/GTP, ATP-GTP binding site motif.