Regensburg 2004 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 50: Poster Session "Biological Physics"
AKB 50.31: Poster
Freitag, 12. März 2004, 10:30–13:00, B
Modelling of Rhodopsin Chromophore — •Minoru Sugihara1, Ana-Nicoleta Bondar2, Peter Entel1, Volker Buss3, and Marcus Elstner4 — 1Institute of Physics, University of Duisburg-Essen — 2IWR, University of Heidelberg — 3Institute of Chemistry, University of Duisburg-Essen — 4Institute of Physics, University of Paderborn
Bovine retinal photoreceptor rhodopsin is the only one visual pigment whose three-dimensional atomic coordinates are available now [1,2]. It is composed of the 40-kDa apoprotein opsin (348 amino acids) and its chromophore. The chromophore of rhodopsin is 11-it cis-retinal which is covalently attached to Lys296 via a Schiff base. The Schiff base nitrogen atom is protonated and there is a salt-bridge between the protonated Schiff base and its counterion, Glu113. Illumination of light of ∼ 500nm leads to photoisomerization from 11-cis retinal to all-trans within 200fs, which is the primary event in visual system and is the only light-dependent step. This is followed by a conformational change in the protein and after a series of intermediates, the pigment reaches the signaling state, the so-called meta-II. In the present work we focus on the modelling of the chromophore in the dark state (rhodopsin state) and the first intermediate state (batho state) based on the crystal structure of rhodopsin state [2]. We use the recently developed quantum mechanical / molecular mechanical (QM/MM) method [3]. [1] K. Palczewski, et al. Science 2000, 289, 739. [2] T. Okada, et al. Proc. Natl. Acad. Sci, U.S.A. 2002, 99, 5982. [3] Q. Cui, et al. J. Phys. Chem. B 2001, 20, 569.