Cloning and Expression of Brucella Outer Membrane Protein 36kDa (OMP2b) in E. coli

Brucellosis is an important zoonotic disease of economic significance. Brucella species are gram-negative, facultative intracellular bacteria, and are capable of replicating in the phagosomes of macrophages. They cause infection in several animal species and humans. Prevention of new diseases and diagnosis of cases infected with the organism are both essential for eradication of the disease. Characterization and evaluation of different antigens of Brucella cells has a key role in progression of prevention and diagnosis programs. Here, we report the production and purification of recombinant 3 kDa outer membrane protein Brucella abortus (Omp2b). Brucella abortus 36kDa outer membrane protein gene was amplified with PrimeSTAR® HS DNA polymerase, cloned in pJET1.2. The target gene was subcloned in pET28a (+). Recombinant pET28a vectors were transformed into E coli BL21 (DE3). Expression of recombinant protein was induced with 1mM IPTG. Proteins were absorbed to Ni-NTA agarose resins and Recombinant proteins were eluted with 250mM imidazol. Imidazol removed by dialysis. Proteins were assayed by Western-blotting and rOmp2b was probed by Brucella rabbit anti serum. Appearance of a golden brown band at the site of reaction, in Western blotting confirmed successfully clone and expression. We purified Omp2b by affinity chromatography and this method prepared refolds proteins on the column. Omp2b were successfully cloned, expressed and purified. The recombinant proteins were recognized by polyclonal antiserum which suggests the accuracy of procedure.