The underlying dynamic exchange that dictates serine protease function

University Of Colorado At Denver, Aurora CO

Investigators

Abstract

Proteases comprise a large group of enzymes responsible for cleaving (or processing) a wide array of substrates. One class of proteases, called serine proteases, are predicted to move between inactive and active conformations. These movements are critical for serine proteases to function and represent one of the clearest examples of why the ability of an enzyme to move is so important for their functions. In this research, a single site within the serine protease called exfoliative toxin (ETA) has been identified that moves this enzyme either completely to its inactive or active conformation. By changing this single site through mutagenesis of the natural amino acid, the explicit inactive and active structures of ETA can be determined. Further methods will also be used to understand how different parts of ETA communicate this conformational change between inactive and active conformations to different parts of the enzyme, referred to generally as “allostery”. This project will train students through multiple programs, including the School of Medicine Colorado Research Experiences (CORE). This research will capitalize on the novel identification of a single inherently dynamic residue, ETA D164, situated adjacent to the active site. This residue acts as a pivotal “switch” that governs the inherent global sampling of inactive and active conformations, as proposed for serine proteases over a decade ago. Through mutagenesis, shifts in solution ensembles are observed as monitored via chemical shift perturbations (CSPs) in either of two directions which correlates to activity to shift in either of two directions. Thus, the goals in this research are to 1) Identify the allosteric networks coupled within ETA that modulate global sampling of inactive and active conformations and 2) determine both the dynamic and structural basis of this sampling of inactive and active conformations. This project is supported by the Molecular Biophysics Cluster of the Division of Molecular and Cellular Biosciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.