Multiple sequence alignments of the XS domain. Figures have been generated using the Jalview program written by Michele Clamp. The protein identifiers are given as name_accession number_species/start-end. The five letter species designations are those used in SWISS-PROT. Alignments are colored using the ClustalX scheme in Jalview (orange: glycine (G); gold: Proline (P); blue: small and hydrophobic amino-acids (A, V, L, I, M, F, W); green: hydroxyl and amine amino-acids (S, T, N, Q); magenta: negative-charged amino-acids (D, E); red: positive-charged amino-acids (R, K); dark-blue: histidine (H) and tyrosine (Y)).