Cloning, expression and anticancer activity of azurin from Pseudomonas aeruginosa VTCC-B-657

Abstract

Azurin, a small molecular weight protein produced by Pseudomonas aeruginosa and several gram-negative bacteria has received considerable attention because of its potential anti-parasitic, anti-viral and anti-cancer activity. In this study, 437 bp-gene of azurin was amplified and cloned from Pseudomonas aeruginosa VTCC-B-657. This gene was then inserted into the PET22b+ vector and the recombinant plasmid was introduced into Escherichia coli BL21(DE3) by chemical methods. The recombinant strain was checked by polymerase chain reaction method and sequencing analysis. Next, the recombinant azurin (r-Azu) was expressed and purified by Ni2+-ProBondTM resin column. The molecular mass of purified r-Azu was 16 kDa when determined by SDS-PAGE and was 13.88 kDa when determined by LC/MS. Interestingly, the purified r-Azu showed cytostatic activity only on breast cancer cell lines (MCF-7 and MDA with IC50 of 25.4 and 29.25 μg/ml respectively) but not on normal cells. These results suggest that r-Azu would be a potential candidate for anticancer drugs and deserves further study.