Origin of Fluorescence in 11-cis Locked Bovine Rhodopsin

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• 作者：Elena N. Laricheva ; Samer Gozem ; Silvia Rinaldi ; Federico Melaccio ; Alessio Valentini ; Massimo Olivucci
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2012
• 出版时间：August 14, 2012
• 年：2012
• 卷：8
• 期：8
• 页码：2559-2563
• 全文大小：326K
• 年卷期：v.8,no.8(August 14, 2012)
• ISSN：1549-9626

文摘

The excited state lifetime of bovine rhodopsin (Rh) increases from ca. 100 fs to 85 ps when the C11鈺怌12 bond of its chromophore is locked by a cyclopentene moiety (Rh5). To explain such an increase, we employed ab initio multiconfigurational quantum chemistry to construct computer models of Rh and Rh5 and to investigate the shape of their excited state potential energy surfaces in a comparative way. Our results show that the observed Rh5 fluorescence (位_max^f = 620 nm) is due to a previously unreported locally excited intermediate whose lifetime is controlled by a small energy barrier. The analysis of the properties and decay path of such an intermediate provides useful information for engineering rhodopsin variants with augmented fluorescence efficiencies.