Conformational Mapping of Dynamic Protein Systems by PELDOR Spectroscopy

Abstract

Understanding the relationship between protein structure and function remains a large challenge in protein biochemistry. In particular, large multi-domain proteins pose challenges for determining their dynamic behavior due to their size and complexity. In this thesis, we study several complex proteins including nitric oxide synthase (NOS), Cytochrome P450-BM-3 (CYP102A1), and calmodulin. All of these proteins show dynamic motion when binding to ligands or cofactors, but how these events change protein structure, and how this is linked to protein function, is not well understood, and in the case of NOS and BM-3 there are not even any full-length high-resolution structures. Here, we utilize a synergistic combination of pulsed electron paramagnetic resonance (EPR) spectroscopy (PELDOR) and computational methods to illuminate protein structural dynamics (CaM and NOS) and domain architecture (BM-3). We reveal that the high-resolution structures of the major states of calmodulin are representative of its behavior in solution. We also investigate its function with NOS and develop spin labelling tools using non-natural amino acids which can be used to further probe NOS structure. Finally, we develop a model for full-length BM-3 based on EPR and computational data. Taken together, our results reveal the importance of protein dynamics in protein structure and function and highlight the importance of methods like PELDOR in revealing these motions.

Date of Award	1 Aug 2019
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Nigel Scrutton (Supervisor), Sam Hay (Supervisor) & Stephen Rigby (Supervisor)