Studying the interaction of membrane enzyme PgIB with substrate and inhibitory peptide

During the catalytic cycle of enzymatic reactions, the recognition of a specific substrate by the enzyme is one of the most important steps, and the analysis of the affinity between enzyme and substrates and/or inhibitors is an important aspect in mechanistic biochemistry. Here, we have performed an analysis of the binding affinity between two different peptides and the bacterial oligosaccharyltransferase, PglB. We have performed MicroScale Themophoresis experiments to determine the Kd values for the interaction between PglB and fluorescently labeled peptides. The results show a high concordance with previously reported values for the same interaction which were determined by fluorescence anisotropy, showing that MST is a suitable tool for the study of membrane protein-substrate interactions in detergent solutions.