Engineering and Development of a Novel Chimera of HBHA-OMP25 as a Potent Recombinant Vaccine Against Brucellosis: A Bioinformatics Investigation

Brucellosis is a zoonotic disease widely reported in most developing countries. Despite vaccination programs for domestic animals, this disease continues to cause economic losses and human infections.

The current project aimed to design a recombinant construct using a bioinformatics approach against brucellosis.

To design the recombinant construct, amino acid sequences of heparin-binding hemagglutinin adhesin (HBHA) and outer membrane protein 25 (OMP25) were collected from databases, and then the HBHA-OMP25 chimera was assembled using an appropriate linker. The most important physical and chemical features, antigenicity, secondary structure, three-dimensional structure, and structural refinement of the designed chimera were evaluated using the best online tools. Moreover, the interaction between the HBHA moiety of the designed chimera (as a ligand) and toll-like receptor 4 (TLR4)/MD2 (as a receptor) was assessed using protein-protein docking. Finally, the codons of the coding DNA sequence of the designed construct were adapted using the JCat tool and cloned into pET21a (+).

The findings confirmed that the designed construct, with a protein weight of 45.172 kDa and an antigenicity index of 0.7184, was an antigenic protein capable of triggering immune responses. Additionally, our results demonstrated that the HBHA moiety of the designed chimera could interact with the TLR4/MD2 receptor using nine hydrogen bonds. Finally, our results showed that the designed chimera, with a codon adaptation index (CAI) of 0.97, was successfully cloned into pET21a (+) between the BamHI and NotI restriction enzymes.

It seems that our designed chimera could be an appropriate candidate for combating brucellosis.