We could not identify a few other

immunogenic surface proteins visible on western blot. C. perfringens ATCC13124 cells were grown on CMM and TPYG till late exponential phase and equal amount of whole cell lysate was separated on one dimensional SDS-PAGE. Western blot was generated using polyclonal serum from mice surviving gas gangrene infection (Figure 4); highlighting proteins recognized by antibodies from C. perfringens infected mice. Remarkable differences were observed in the profile of immunogenic proteins, especially in the regions corresponding to molecular #selleckchem randurls[1|1|,|CHEM1|]# masses of 40–42 kDa and 58–60 kDa. Figure 4 Western blot analysis of immunogenic proteins of whole cell lysate of C. perfringens grown on TPYG (lane 1) and CMM (lane 2). Protein was separated on 12% SDS-PAGE and transferred onto PVDF membrane. Mouse anti- C. perfringens serum (obtained from animals that survived experimental gas gangrene infection) was used to probe

the blot and bound antibodies were detected by Goat anti-mouse IgG HRP conjugate find more by chemiluminescence using and ECL western blot kit (Sigma). Sequence analysis of identified proteins Based on blast search results, all the proteins identified in the present investigation appeared to be highly conserved (showing 94–100% amino acid identity and 97–100% amino acid similarity) among C. perfringens strains and were not strain specific (based on whole genome sequence data for 8 strains available in database) [see Additional file 6]. Most of the proteins (32%) were also conserved among other clostridial members showing >70% amino Phosphoprotein phosphatase acid sequence identity. Sucrose-6-phosphate dehydrogenase, threonine dehydratase, and N-acetylmuramoyl-L-alanine amidase exhibited 50–60% sequence identity while choloylglycine hydrolase family protein, cell wall-associated serine proteinase, and rhomboid family protein shared only <50% identity with their closest homologs in bacterial domain. All the identified proteins were analyzed using various bioinformatics software programs, such as SignalP,

SecretomeP, PSORT, LipoP, TMHMM, and PROSITE for predicting protein secretion and localization. For instance, N-acetylmuramoyl-L-alanine amidase and cell wall-associated serine proteinase obtained from cell surface fraction of strain ATCC13124 were predicted by SignalP to be secreted in the classical Sec pathway, which is characterized by the presence of a signal peptide [19] [see Additional file 7]. Both these proteins containing the signal peptides possessed cleavage site for signal peptidase 1 (spI). Interestingly, cell wall-associated serine proteinase was also predicted; to harbor two transmembrane helices (TMHMM), suggesting an extracytoplasmic but cell-associated location; contain an LPxTG motif (PROSITE scan) for cell wall anchorage; and a cell wall associated localization (PSORT). PSORT algorithm predicted most of the proteins (49%) to have cytoplasmic localization.