SERRS and ET in Proteins

HILDEBRANDT, P.; ALVAREZ PAGGI, D.; FENG, J. J.; KRANICH, A.; LY, K. H.; MARTÍ, M. A.; MARTÍN, D. F.; MURGIDA, D. H.; WISITRUANGSAKUL, N.; SEZER, M.; WEIDINGER, I.M.; ZEBGER, I.

Surface Enhanced Raman Spectroscopy: Analytical, Biophysical and Life Science Applications

WILEY-VCH, INC

Lugar: Weinhein; Año: 2010;

Electron  transfer (ET) reactions represent key steps in biological energy transduction and conversion as well as in many enzymatic processes. Prominent examples are the oxidative phosphorylation in the respiratory chain and the light driven water splitting in photosynthesis §). These processes as well as many others take place at or in membranes involving integral or peripherally bound redox proteins. Membrane-based electron relays are based on a well-defined spatial arrangement of the redox partners with respect to each other, a prerequisite for efficient protein-protein ET processes. However, reaction conditions at membrane interfaces deviate substantially from those in the bulk since mobility of the reaction partners is restricted and dielectrics of the reaction medium  are quite different. The most prominent difference, however, refers to the local electric fields.  At membranes, electrical potentials arise from different ion concentrations at both sides of the membrane, the distribution of charged and uncharged lipid head groups, and the alignment of molecular dipoles of lipids and water molecules in the membrane/solvent interfaces  (§). As a consequence, the potential follows a rather complex profile across the membrane. Particularly pronounced potential changes occur in the interfacial regions where local electric field strengths may approach 109 V⋅m-1, which are likely to affect structures and processes of integrated  and membrane-attached  proteins