Use of a Paramagnetic Spin Label for Determination of Long-Range Distance Constraints in Solid-State NMR

Date

2014-08-12

Authors

O'Halloran, Matthew

Journal Title

Journal ISSN

Volume Title

Publisher

University of Guelph

Abstract

Solid-State Nuclear Magnetic Resonance (SSNMR), with paramagnetic relaxation enhancement (PRE), is used to investigate the protein Proteorhodopsin (PR). PRE allows for the acquisition of long-range distance constraints not accessible through standard NMR experiments. Four mutant versions of PR, created to have only one cysteine residue in each, were investigated. The S215C mutant did not purify well and appeared to retain a large amount of detergent. The S55C variant was found to differ significantly from the wild-type structure. The C107 mutant experienced delocalized PRE effects originally thought to be due to proton spin diffusion, when this interaction was removed to the first order using Lee-Goldburg cross-polarization (CP), the delocalized effect was still observed. The C175 mutant produced long-range distance restraints that can be used to restrain three of the helices in the bundle on the cytoplasmic side. Future studies are required to better understand the structure of this membrane protein.

Description

Keywords

Solid State Nuclear Magnetic Resonance (SSNMR), Paramagnetic Relaxation Enhancement (PRE), Membrane Proteins, Proteorhodopsin (PR), Site Specific Labelling

Citation