Alignment of the sPPase sequences of M. suis , selected Mycoplasma species and Escherichia coli. Sequences were aligned using the ClustalW tool http://www.ebi.ac.uk/Tools/clustalw2/. The 13 conserved residues which build the active site (Sivula et al., 1999) are bold-faced and underlined. The residues which are essential for the cation binding are emphasized by a grey box. Accession numbers for the sequences follow: M. mycoides ssp mycoides SC str. PG1 NC_005364; M. capricolum ssp capricolum CP000123; M. suis FN394679; M. genitalium L43967; M. pneumonia e U00089; M. penetrans NC_004432; U. urealyticum serovar 10 NC_011374; M. gallisepticum AE015450; M. hyopneumoniae NC_007295; E. coli NC_010468.