Solid-state NMR study of proteorhodopsin in the lipid environment: secondary structure and dynamics.
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 (13)C,(15)N-labelled sample. These experiments provided the assignments for 153 residues, with a particularly high density in the transmembrane regions ( approximately 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.
Shi
Lichi
L
Department of Physics, University of Guelph, Ontario, Canada N1G 2W1.
Lake
Evelyn M R
EM
Ahmed
Mumdooh A M
MA
Brown
Leonid S
LS
Ladizhansky
Vladimir
V
D001419:Bacteria / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D017433:Protein Structure, Secondary / Q000502:physiology; D012243:Rhodopsin / Q000737:chemistry* / Q000235:genetics; D025604:Rhodopsins, Microbial
D001426:Bacterial Proteins; D025604:Rhodopsins, Microbial; C413548:proteorhodopsin; D012243:Rhodopsin