Recombinant expression of YchP outer membrane protein from salmonella enterica serovar typhimurium and its biophysical characterization

Abstract

Salmonella enterica serovar Typhimurium is a gram-negative pathogenic bacterium. OMPs from gram-negative bacteria play various functional roles including causing virulence. Till now few of OMPs have been studied in Salmonella such as OmpC, OmpD, OmpA, OmpF, etc. YchP is another putative invasin OMP from Salmonella, which has an affinity for β-integrin present on the mammalian host cell surface and plays an important role in invasion into host cells and causing virulence. In-silico analysis of YchP (~52kDa) shows that it is a β-barrel OMP, containing 41 residue long signal peptide and 14 tryptophan residues. The biophysical study of YchP indicate that it may be exists as a monomer. Refolding and secondary structure analysis of YchP were done under different conditions of buffer containing urea (denaturant), lipids, and detergents using techniques such as tryptophan fluorimetry, CD spectroscopy, and ATR-FTIR spectroscopy. Our study provides the structural information of YchP OMP, which may help us in understanding the pathogenesis caused by YchP OMP in Salmonella. Keywords: Gram-negative bacteria, OMP, invasin, integrin, pathogenesis.