Site-Specific Solid-State NMR Detection of Hydrogen-Deuterium Exchange Reveals Conformational Changes in a 7-Helical Transmembrane Protein

• Published in: Biophysical journal Vol. 101; no. 3; pp. L23 - L25
• Main Authors: Wang, Shenlin, Shi, Lichi, Kawamura, Izuru, Brown, Leonid S., Ladizhansky, Vladimir
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 03-08-2011; Biophysical Society; The Biophysical Society
• Subjects: Anabaena; Bacterial Proteins - chemistry; Biophysical Letter; Biophysics; Cytoplasm; Deuterium Exchange Measurement; membrane proteins; Models, Molecular; nuclear magnetic resonance spectroscopy; Nuclear Magnetic Resonance, Biomolecular; Pigments; Protein Structure, Secondary; Proteins; rhodopsin; Rhodopsin - chemistry; Solid state physics; Spectrum analysis
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/j.bpj.2011.06.035

Solid-state NMR spectroscopy is an efficient tool for following conformational dynamics of membrane proteins at atomic resolution. We used this technique for the site-specific detection of light-induced hydrogen-deuterium exchange in the lipid-embedded heptahelical transmembrane photosensor
Anabaena sensory rhodopsin to pinpoint the location of its conformational changes upon activation. We show that the light-induced conformational changes result in a dramatic, but localized, increase in the exchange in the transmembrane regions. Most notably, the cytoplasmic half of helix G and the cytoplasmic ends of helices B and C exchange more extensively, probably as a result of their relative displacement in the activated state, allowing water to penetrate into the core of the protein. These light-induced rearrangements must provide the structural basis for the photosensory function of
Anabaena sensory rhodopsin.