Solid-state 2H NMR structure of retinal in metarhodopsin I

Gilmar F.J. Salgado, Andrey V. Struts, Katsunori Tanaka, Sonja Krane, Koji Nakanishi, Michael F. Brown

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

The structural and photochemical changes in rhodopsin due to absorption of light are crucial for understanding the process of visual signaling. We investigated the structure of trans-retinal in the metarhodopsin I photointermediate (MI), where the retinylidene cofactor functions as an antagonist. Rhodopsin was regenerated using retinal that was 2H-labeled at the C5, C9, or C13 methyl groups and was reconstituted with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. Membranes were aligned by isopotential centrifugation, and rhodopsin in the supported bilayers was then bleached and cryotrapped in the MI state. Solid-state 2H NMR spectra of oriented rhodopsin in the low-temperature lipid gel state were analyzed in terms of a static uniaxial distribution (Nevzorov, A. A.; Moltke, S.; Heyn, M. P.; Brown, M. F. J. Am. Chem. Soc. 1999, 121, 7636-7643). The line shape analysis allowed us to obtain the methyl bond orientations relative to the membrane normal in the presence of substantial alignment disorder (mosaic spread). Relative orientations of the methyl groups were used to calculate effective torsional angles between the three different planes that represent the polyene chain and the β-ionone ring of retinal. Assuming a three-plane model, a less distorted structure was found for retinal in MI compared to the dark state. Our results are pertinent to how photonic energy is channeled within the protein to allow the strained retinal conformation to relax, thereby forming the activated state of the receptor.

Original languageEnglish (US)
Pages (from-to)11067-11071
Number of pages5
JournalJournal of the American Chemical Society
Volume128
Issue number34
DOIs
StatePublished - Aug 30 2006

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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    Salgado, G. F. J., Struts, A. V., Tanaka, K., Krane, S., Nakanishi, K., & Brown, M. F. (2006). Solid-state 2H NMR structure of retinal in metarhodopsin I. Journal of the American Chemical Society, 128(34), 11067-11071. https://doi.org/10.1021/ja058738+