Proteorhodopsins are typical retinal-binding light-driven proton pumps of heptahelical architecture widely distributed in marine and freshwater bacteria. Recently, we have shown that green proteorhodopsin (GPR) can be prepared in a lipid-bound state that gives well-resolved magic angle spinning (MAS) NMR spectra in samples with different patterns of reverse labelling. Here, we present 3D and 4D sequential chemical shift assignments identified through experiments conducted on a uniformly 13C,15N-labelled sample. These experiments provided the assignments for 153 residues, with a particularly high density in the transmembrane regions (∼ 74% of residues). The extent of assignments permitted a detailed examination of the secondary structure and dynamics in GPR. In particular, we present experimental evidence of mobility of the protein's termini and of the A-B, C-D, and F-G loops, the latter being possibly coupled to the GPR ion-transporting function. © 2009 Elsevier B.V. All rights reserved.
Shi, L., Lake, E. M. R., Ahmed, M. A. M., Brown, L. S., & Ladizhansky, V. (2009). Solid-state NMR study of proteorhodopsin in the lipid environment: Secondary structure and dynamics. Biochimica et Biophysica Acta - Biomembranes, 1788(12), 2563–2574. https://doi.org/10.1016/j.bbamem.2009.09.011