Direct proton transfer in a putative L-state intermediate of the bacteriorhodopsin photocycle |
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| Authors: | AN Bondar M Elstner S Suhai S Fischer JC Smith |
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| Institution: | 1. Computational Molecular Biophysics , IWR, University of Heidelberg , Im Neuenheimer Feld 368, D-69120 Heidelberg, Germany;2. Department of Molecular Biophysics German Cancer Research Center , Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany;3. Department of Molecular Biophysics German Cancer Research Center , Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany;4. Computational Molecular Biophysics , IWR, University of Heidelberg , Im Neuenheimer Feld 368, D-69120 Heidelberg, Germany |
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| Abstract: | In the light-driven proton pump bacteriorhodopsin, photoisomerization of the all-trans retinal chromophore triggers a photocycle whose net effect is the transfer of one proton from the cytoplasmic to the extracellular side of the membrane. The first proton transfer step, from the retinal Schiff base to Asp85, occurs between the L and M intermediate states. Details of the geometry of the retinal binding region are important for the pathway followed by the proton. Here we report some preliminary results on combined Quantum Mechanical/Molecular Mechanical reaction path calculations for retinal deprotonation and discuss the hydrogen-bonding pattern in the active site. |
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| Keywords: | Bacteriorhodopsin Proton transfer QM/MM |
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