Cloning and expression of C-terminal β-Barrel outer membrane protein 85 of aeromonas hydrophila

Abstract

Aeromonas hydrophila is a gram-negative bacterium that causes diseases for a variety of aquatic animals, especially hemorrhagic septicemia disease in striped catfish. It has resulted in high economic losses to fish farming throughout the world. It is essential to develop recombinant vaccine against this bacterium infection. In this study, the gene encoding for C-terminal β-barrel outer membrane protein 85 (Omp85) was amplified from the A. hydrophila B66 strain by PCR, cloned in pET28a vector, sequenced and expressed in Rosetta E. coli expression strain by isopropyl-β- thiogalactoside (IPTG) induction. The estimated molecular weight of the expressed protein is 40 kD. The recombinant protein showed the best expression with 0.075 mM IPTG induction at 28C-overnight. The BLAST analysis revealed that partial recombinant Omp85 proteins had high similarity with others A. hydrophila strains that are ML09-119, AL09-71, J-1 and ATCC 7966. The recombinant protein was purified by Ni-NTA affinity chromatography with high yields. The recombinant protein could be used for further investigation for vaccine development against A. hydrophila infection. Keywords: Aeromonas hydrophila Cloning expression Outer membrane protein Striped catfish