Catalysis of Ground State cis\(\rightarrow\) trans Isomerization of Bacteriorhodopsin’s Retinal Chromophore by a Hydrogen-Bond Network
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For the photocycle of the membrane protein bacteriorhodopsin to proceed efficiently, the thermal 13-cis to all-trans back-isomerization of the retinal chromophore must return the protein to its resting state on a time-scale of milliseconds. Here, we report on quantum mechanical/molecular mechanical energy calculations examining the structural and energetic determinants of the retinal cis–trans isomerization in the protein environment. The results suggest that a hydrogen-bonded network consisting of the retinal Schiff base, active site amino acid residues, and water molecules can stabilize the twisted retinal, thus reducing the intrinsic energy cost of the cis–trans thermal isomerization barrier.
KeywordsBacteriorhodopsin Retinal Isomerization QM/MM Energy Calculations
N. E.-M. and J. C. S. were supported by a grant from the Deutsche Forschungsgemeinschaft (DFG), SM 63/7-3. P. P. and M. E. were supported by a grant from the Deutsche Forschungsgemeinschaft (DFG), EL 206/8-1.
This study was funded by Grants SM 63/7-3 and EL 206/8-1 from the Deutsche Forschungsgemeinschaft. N. E.-M. gratefully acknowledges financial support in part from the Volkswagen Stiftung (grant number 86 539). A.N. B acknowledges financial support in part from the DFG Collaborative Research Center SFB1078’ Protonation Dynamics in Protein Function’ (Project C4) and from the Freie Universitt Berlin within the Excellence Initiative of the German Research Foundation.
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Conflict of interest
All authors declare no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- MacKerell AD Jr, Bashford D, Bellott M, Dunbrack RL Jr, Evanseck JD, Field MJ, Fischer S, Gao J, Guo H, Ha S, Joseph-McCarthy D, Kuchnir L, Kuczera K, Lau FTK, Mattos C, Michnick S, Ngo T, Nguyen DT, Prodhom B, Reiher WE III, Roux B, Schlenkrich M, Smith JC, Stote R, Straub J, Watanabe M, Wiórkiewicz-Kuczera J, Yin D, Karplus M (1998) All-atom empirical potential for molecular modeling and dynamics studies of proteins. J Phys Chem B 102:3586–3616CrossRefPubMedGoogle Scholar
- Nango A, Royant A, Kubo M, Nakane T, Wickstrand C, Kimura T, Tanaka T, Tono K, Song C, Tanaka R, Arima T, Yamashita A, Kobayashi J, Hosaka T, Mizohata E, Nogly P, Sugahara M, Nam D, Nomura T, Shimamura T, Im D, Fujiwara T, Yamanaka Y, Jeon B, Nishizawa T, Oda K, Fukuda M, Andersson R, Bøath P, Dods R, Davidsson J, Matsuoka S, Kawatake S, Murata M, Nureki O, Owada S, Kameshima T, Hatsui T, Joti Y, Schertler G, Yabashi M, Bondar A-N, Standfuss J, Neutze R, Iwata S (2016) A three-dimensional movie of structural changes in bacteriorhodopsin. Science 354:1552–1557CrossRefPubMedGoogle Scholar
- Warshel A (1991) A computer modeling of chemical reactions in enzymes and solutions. Wiley, New YorkGoogle Scholar