[Tandem expression and activity determination of antibacterial peptide Spinosan-C from Paa spinosa].

Antibacterial peptide can be easily degraded by protease and has the lethal effect on the host Escherichia coli. In order to solve these problems and further improve the expression ability of the Escherichia coli system, the antimicrobial peptide Spinosan-C of Paa spinosa was studied. First, the codon of Spinosan-C was optimized according to E. coli codon usage frequency. Then, the 8 multimeric Spinosan-C gene (8×Spinosan-C) was synthesized and cloned into prokaryotic expression vector pET-28a. The fusion antimicrobial peptide 8×Spinosan-C was further highly expressed in Escherichia coli strain Rosetta. The recombinant 8×Spinosan-C protein was then purified and cleaved specially by formic acid to generate the Spinosan-C monomer. Antibacterial test in vitro suggested that the cleaved Spinosan-C monomer had antibacterial bioactivity against the test bacteria. This study provides a technical reference for the largescale preparation of frog antimicrobial peptides.