Accession Number : ADA271599

Title :   Role of Water in Proton-Hydroxide Conductance Across Model and Biological Membranes.

Descriptive Note : Final technical rept. for period ending Sep 92.

Corporate Author : CALIFORNIA UNIV DAVIS

Personal Author(s) : Deamer, David W.

Report Date : 25 OCT 1993

Pagination or Media Count : 7

Abstract : Our research effort focused on proton flux mechanisms, building on our original observation that protons diffuse across lipid bilayer membranes by a process quite different from that of other cations. As a working hypothesis, we proposed that proton equivalents move along hydrogen bonded chains of water molecules which occur in transient defects in the bilayer. We have extended this concept to the action of certain membrane perturbants on the bilayer. We are also working with a known hydrogen bonded chain of water - the gramicidin channel - and have proposed that proton conductance along similar water structures may play a role in biological membranes as well. The results provide insight into the nature of the lipid bilayer, and the manner in which hydrated defects contributed to ion permeation across the bilayer barrier. It has also permitted us to better understand the effects of anesthetic molecules on the ability of synaptic vesicles to maintain proton gradients necessary for neurotransmitter uptake. Finally, our most recent results suggest that hydrogen bonded chains of water may be involved in conducting proton equivalents through the Fo subunit of coupling membranes. Lipid bilayer membranes, Proton flux, Hydrogen bonded chains of water.

Descriptors :   *CHANNELS, *HYDROGEN, *MEMBRANES(BIOLOGY), *PROTONS, ANESTHETICS, BARRIERS, BUILDINGS, CATIONS, CHAINS, COUPLING(INTERACTION), GRADIENTS, IONS, LIPIDS, MOLECULES, NEUROTRANSMITTERS, OBSERVATION, RECREATION, STRUCTURES, TRANSIENTS, WATER, BONDED JOINTS, DECAY, DEFECTS(MATERIALS), ELECTRON TRANSPORT, FLUX(RATE), PARTICLE FLUX, PHOSPHORYLATION, PLANAR STRUCTURES, TEST AND EVALUATION.

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE