Determination of Low Molecular weight Immunogenic Omp28 Protein and Gene of Salmonella typhimurium

Abstract

Outer membrane of Gram-negative bacteria has complex profile of proteins. The outer membrane proteins (OMPs) isolated from S. typhimurium by urea-EDTA extraction method and analysed through SDS-PAGE showed a complex electrophoretic profile having more than 15 low molecular weight proteins with molecular masses ranging between 3.5 and 43 kDa. The most important outer membrane protein (Omp28) of S. typhimurium with submolecular masses of 12.32kDa of main protein was recovered. The gene responsible for expression of this protein was also amplified through PCR and sequenced, showed 341bp amplicon size and predicted amino acid sequence of this pro-tein was determined. The Antigenic index was calculated from amino acid sequence of same gene and found 2.2 (0.1-2.2) suggesting highly antigenic in nature. The experimentally determined values are close agreement with the theoretically calculated molecular weight 12.32 kDa and pI: 9.61 from the gene sequence of this protein. The antigenic natures of predicted protein values are close agreement with experimental determent of Omp28 of S. typhimurium a possible formula for vaccine developmental of genus Salmonella.