Electric field effects in proteins in membranes.

Both the organization and function of protein nanostructures in membranes are related to the substructural properties of the lipid portion of the membrane. Potential differences that are established across the membrane and generate electric fields in these very thin portions are shown to modulate the organizational and functional properties of the protein modules. Many protein modules also have nonisotropic distributions of charged sites, including configurations in which there are regions containing predominantly positive fixed charges, juxtaposed with adjacent regions containing predominantly negative fixed charges. In these double fixed charge regions, very large electric fields can manifest in the ionic depletion layer at the junction of the two fixed charge regions. Consideration is also given to the manner in which the intense electric fields that are established in protein modules, such as proton ATPases, can modulate the chemical reactions that are associated with proton transport and dehydration reactions.