Abstract
We have made calculations of the effects of dielectric solvation and electrostatic interactions on the titration of ionizable groups in bacteriorhodopsin. The results are in reasonable agreement with experiment when an ambiguity in the placement of Arg82 is resolved in favor of a conformation with the side chain pointing “up” towards the Schiff base. We therefore propose such a conformations for Arg82 and suggest that this strengthens the case for the involvement of this group in the proton release pathway. Our results also suggest that complex titration curves and the tendency to form charges in opposite pairs or larger complexes may be common in membrane proteins with buried ionizable groups and in proton transfer systems.
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Bashford, D., Gerwert, K. (1992). Electrostatic Calculations of the pK a ’s of Ionizable Groups in Bacteriorhodopsin. In: Pullman, A., Jortner, J., Pullman, B. (eds) Membrane Proteins: Structures, Interactions and Models. The Jerusalem Symposia on Quantum Chemistry and Biochemistry, vol 25. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-2718-9_10
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DOI: https://doi.org/10.1007/978-94-011-2718-9_10
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