Abstract: Bacterioferritin (Bfr) is a member of the ferritin family and plays an important role in intracellular iron metabolism. In order to probe the function of the Bfr gene, the gDNA of Pseudomonas spp. was isolated and used as templates to amplify the Bfr gene by PCR. Subsequently, the sequenced fragments were subcloned into pGEX-4T-1 vector. The recombinant vector was transformed into E. coli BL21 (DE3) and induced by IPTG. The GST-Bfr protein and Bfr protein were isolated and purified by GST-resin purification column, and then identified by Western blot. Finally, iron chelation examination was investigated. The results showed that the prokaryotic expression vector pGEX-4T-1-Bfr was successfully constructed. SDS-PAGE and Western blot displayed that fusion protein GST-Bfr and Bfr were both purified. Iron chelation assay suggested that GST-Bfr protein could not bind Fe3+ and Fe2+, while Bfr could bind Fe3+ but could not bind Fe2+. Liquid culture experiments further showed that recombinant Bfr could promote the vegetative growth of Pseudomonas spp. to a certain extent. These results provide a theoretical basis for further study of gene function of bacterioferritin.

Key words: Pseudomonas, bacterioferritin, protein purification, iron chelation