Fluorine-induced polarity increases inhibitory activity of BPTI towards chymotrypsin

Substituting the P-1 position in bovine pancreatic trypsin inhibitor (BPTI) is known to heavily influence its inhibitory activity towards serine proteases. Side-chain fluorinated aliphatic amino acids have been shown to alter numerous properties of peptides and proteins and thus are of interest in the context of BPTI. In our study, we systematically investigated the site-specific incorporation of non-canonical amino acids into BPTI by microwave-assisted solid-phase peptide synthesis (SPPS). Inhibitor activity of the variants was tested towards the serine protease alpha-chymotrypsin. We observed enhanced inhibition of two fluorinated BPTIs compared to wild type and hydrocarbon variants. To further investigate the complexes, we performed X-ray structure analysis. Our findings underline the power fluorine offers as a tool in protein engineering to beneficially alter the effects on phenomena as protein-protein interactions.

Automated summary

This study systematically investigated the site-specific incorporation of non-canonical amino acids into BPTI using microwave-assisted solid-phase peptide synthesis. It was found that fluorinated BPTI showed enhanced inhibitory activity towards serine protease, and the complex structures were further analyzed using X-ray analysis. These findings highlight the potential of fluorine as a tool in protein engineering to beneficially alter protein-protein interactions.