Proton transfer reactions across bacteriorhodopsin and along the membrane

Bacteriorhodopsin is probably the best understood proton pump so far and is considered to be a model system for proton translocating membrane proteins . The basis of a molecular description of proton translocation is set by ha ving the luxury of six highly resolved structural models at hand. Details o f the mechanism and reaction dynamics were elucidated by a whole variety of biophysical techniques. The current molecular picture of catalysis by BR w ill be presented with examples from time-resolved spectroscopy. FT-IR spect roscopy monitors single proton transfer events within bacteriorhodopsin and judiciously positioned pH indicators detect proton migration at the membra ne surface. Emerging properties are briefly outlined that underlie the effi cient proton transfer across and along biological membranes. (C) 2000 Elsev ier Science B.V. All rights reserved.