Optimization of the hydroxylamine cleavage of an expressed fusion protein to produce a recombinant antimicrobial peptide

Hydroxylamine was used to cleave the Asn-Gly peptide bond between the fusion partner and the antimicrobial peptide of interest, a magainin derivative (MSI-344). The efficiency of reaction depended on the hydroxylamine concentration, denaturant, pH, and the fused protein concentration. The optimal cleavage solution consisted of guanidine HCl as the denaturant, pH 8.1, and 6.7 mg ml^–1 of fused MSI-344. This optimized cleavage solution resulted in a high yield (95% ) of MSI-344 from a cultivation of E. coli. This result suggests potential applications for using hydroxylamine to cleave basic peptides produced from fusion proteins.