The anti-oxidative activity of Acinetobacter baumannii ferritin protein

Abstract:

[Objective] This study aimed to clone the ferritin gene Abferritin from Acinetobacter baumannii and identify its anti-oxidative activity. [Methods] Relative expression of Abferritin under oxidative stress was analyzed by real-time PCR. The gene encoding sequence of Abferritin was inserted into the pET28a vector to generate the pET28a-Abferritin recombinant plasmid. This plasmid was transformed into the E. coli BL21(DE3) to create transformed strain of BL/pET28a-Abferritin. The Abferritin protein was expressed by IPTG induction and was purified by Ni2+-affinity chromatography. Kinetics of Fe2+ oxidation which catalyzed by Abferritin protein was determined by spectrophotometric analysis. Anti-oxidative activity of Abferritin was examined by the radical scavenging assay. Survival rations of the recombinant and control E. coli under the oxidative stress of H2O2 were also measured. [Results] Expression level of Abferritin was up-regulated in A. baumannii under oxidative stress. Abferritin protein was expressed in E. coli BL21(DE3) and was purified successfully. Ferroxidase activity assay demonstrated that the Abferritin protein could convert Fe2+ to Fe3+. The hydroxyl radicals were scavenged by the Abferritin protein in vitro and the ectopic expression of Abferritin could increase the survival ratios of E. coli cells under the oxidative stress. [Conclusion] Abferritin was strongly up regulated under oxidative stress and the Abferritin protein exhibited ferroxidase and anti-oxidative activity.