suis sPPase, too (Figure 2). Figure 1 Southern blot hybridization of Eco RI-restricted

M. suis DNA showing the genomic location of the ms 262 clone insert on a 1.2- and R428 cell line a 2.7-kb fragment. (A) agarose gel electrophoresis of EcoRI-restricted DNA. (B) the blot probed with the DIG-labeled 950 bp-EcoRI fragment of the library clone ms262; (C) the blot probed with the DIG-labeled 1050 bp-EcoRI fragment of the library clone ms262; (M) molecular weight standard; (Ms) M. suis. The arrows indicate the positions of the hybridized 1.2- and 2.7-kb fragments. (D) schematic map of the ORF localisation on the library clone ms262. The grey box arrows indicate the two ORFs: ppa (inorganic pyrophosphatase) and trx (thioredoxin). Figure 2 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. pneumoniae U00089; M. penetrans

NC_004432; U. urealyticum serovar 10 NC_011374; M. gallisepticum AE015450; M. hyopneumoniae NC_007295; E. coli NC_010468. Expression of recombinant PPase in E. coli The entire ORF of the M. suis ppa was assembled as a synthetic gene and one UGATrp codon at position 274-276 was replaced by UGG. Other changes in the synthetic selleck products ppa were done to optimize the sequence for the heterologous E. coli expression. Induction of E. coli transformants containing the ppa gene resulted in the high-level expression of a 20 kDa-protein as shown in Figure 3A. Recombinant PPase was used to raise a PPase-specific rabbit polyclonal antiserum. The specificity of the rabbit serum was demonstrated by probing an immunoblot

containing purified rPPase and a M. suis preparation. The anti-PPase serum reacted clearly with a single band of 20 kDa corresponding to the purified rPPase. Myosin In the M. suis preparations a weak band of 20 kDa and a clear band of 80 kDa potentially corresponding to a tetrameric form of the M. suis PPase were detected (Figure 3B). No reaction could be observed neither with the blood control preparation of M. suis negative pigs nor the non-induced E. coli control. Figure 3 Expression and immunological characterization of the M. suis sPPase. (A) Coomassie-stained SDS polyacrylamide gel electrophoresis of recombinant M. suis PPase., Co, non-induced IMAC purified E. coli lysate; PPA, IMAC purified recombinant PPase. (B) Immunoblot analysis of recombinant PPase and M. suis whole cell antigen; immunological detection with anti-PPase rabbit immune serum; M, molecular weight standard; PPA, recombinant PPase; Ms, purified M.