A Kunitz-type serine proteinase inhibitor: MBmTISINT - Its cloning, expression, purification and biochemical characterization.
Protease inhibitors have been studied as a promising therapeutic strategy for a wide range of diseases. Proteases have pro-inflammatory activity and are often associated with tissue damage. MBmTIsint is a Kunitz-BPTI-type inhibitor, consisting of an inhibitory domain with 57 amino acids and a molecular mass of 6.5 kDa. It is an modified version of BmTIsint, which is a synthetic chimera of two native inhibitors found in the Rhipicephalus microplus tick.
This work aimed at cloning the gene corresponding to MBmTIsint and its expression in pET26B vector. After expression induction with IPTG, the expression product was purified by affinity chromatography using nickel agarose column and gel-filtration chromatography using G75-Sephadex column, the purity was assessed by SDS-PAGE. It was found that the recombinant protein presented a homogenity increasing during the purification process. Then, enzymatic inhibition tests were performed with bovine pancreatic trypsin. The results showed that MBmTIsint presented a KI in nM range, which demonstrates its inhibitory potential on trypsin.
Another inhibitory activities toward proteases will be investigated in the project.