Optimization of prokaryotic expression conditions of Leptospira interrogans trigeminy genus-specific protein antigen based on surface response analysis

Abstract:

Lipoproteins LipL32 and LipL21 and transmembrane protein OMPL1 have been confirmed as the superficial genus-specific antigens of Leptospira interrogans, which can be used as antigens for developing a universal genetic engi-neering vaccine. [Objective] In order to obtain high expression of an artificial fusion gene lipL32/1-lipL21-ompL1/2, we optimized prokaryotic expression conditions. [Methods] We used surface response analysis based on the central compos-ite design to optimize culture conditions of a new antigen protein by recombinant Escherichia coli DE3.The culture con-ditions included initial pH, induction start time, post-induction time, Isopropyl b-D-thiogalactopyranoside (IPTG) con-centration, and temperature. [Results] The maximal production of antigen protein was 37.78mg/l. The optimal culture conditions for high recombinant fusion protein was determined: initial pH 7.9, induction start time 2.5 h, a post-induction time of 5.38 h, 0.20 mM IPTG, and a post-induction temperature of 31℃.[Conclusion] Surface response analysis based on CCD increased the target production. This statistical method reduced the number of experiments required for optimization and en-abled rapid identification and integration of the key culture condition parameters for optimizing recombinant protein expression.