Accession Number:

ADA244879

Title:

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

Descriptive Note:

Final technical rept.,

Corporate Author:

CALIFORNIA UNIV DAVIS

Personal Author(s):

Report Date:

1990-09-01

Pagination or Media Count:

6.0

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 other cations. The results provide insight into the nature of the lipid bilayer, and the manner in which hydrated defects contribute 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, recent results suggest that hydrogen bonded chains of water may be involved in conducting proton equivalents through the Fo subunit of coupling membranes, and we are now in a position to test this exciting possibility in reconstituted planar membranes. A variety of compounds perturb lipid bilayers in such a way that the barrier to ion flux is reduced. This can lead to inhibition of certain membrane functions that depend on ionic gradients. The classic example is the effect of uncoupling agents on mitochondrial and thylakoid membranes. Uncouplers introduce leaks that allow gradients of protons or other ions to decay, with the result that chemiosmotic phosphorylation is uncoupled from electron transport.

Subject Categories:

  • Biochemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE