Cloning and expression of soluble integration host factor subunit of Vibrio cholerae

Objective To clone and express the subunit of integration host factor (IHF) of Vibrio cholerae. Methods PCR was conducted to amplify the ihfB gene with the chromosome of C7258 as template, the product was cloned into vector pXTB1 after digested by NheⅠ and SapⅠ. N-terminal of ihfB gene and C-terminal of ihfA gene encoding subunit of IHF were joined together by Bridge-PCR amplifying. The recombined PCR product was cloned as NheⅠ-SapⅠ fragment into the expression vector pXTB1. Target protein expression was induced with 0.4 mmol/L IPTG, cell pellet was lysed with sonication treatment, and lysis supernatant was purified with CBD affinity column and eluted by DTT. Results We successfully constructed and expressed the wild-type ihfB gene and the chimera N-ihfB-C-ihfA with the expression vector pXTB1 in the host bacteria in ER2566. In pXTB1-ihfB, the target protein was mainly expressed as insoluble inclusion-body and soluble chimera protein was purified from pXTB1-N-ihfB-C-ihfA. Conclusion C-terminal of IHF- could significantly increase the soluble expression of IHF- and soluble chimera protein containing the N terminal of subunit and C terminal of subunit was successfully expressed and purified, which is the basis for further function study.