Engineering Proteins via Peptide Backbone Mutagenesis

Abstract

The development of proteins/peptides as therapeutic agents has emerged as a promising area for drug design. Due to increased antibiotic resistance, search for novel antibiotics has become a primary area of interest within the pharmaceutical industry. Antimicrobial peptides have been a significantly desirable model due to their innate cytolytic effects and favorable interaction with the membranes of bacterial cells within the host. Thioxylated analogues of biologically active peptides have shown increased enzymatic stability and increased selectivity and potency. Thioamide linkages have thus been installed in a variety of short peptides, replacing the backbone amide linkage, in order to study the effects on peptide conformation and stability. Several bioanalytical tools were used in the analysis including circular dichroism spectroscopy, NMR, size-exclusion high performance liquid chromatography, and fluorescence. The mutation was well-accommodated within several systems, including Trpzip 4 and gramicidin A, and proved to have comparable, and in several cases, enhanced stability in comparison to the wild-type peptides.