Accession Number : ADA194782

Title :   Membrane Voltage Effects on Proton Transport by a Yeast H+ -ATPase.

Descriptive Note : Annual rept. 1 Jun 87-31 May 88,

Corporate Author : PUBLIC HEALTH RESEARCH INST OF THE CITY OF NEW YORK INC DEPT OF BIOCHEMISTRY

Personal Author(s) : Perlin, David S

PDF Url : ADA194782

Report Date : 31 May 1988

Pagination or Media Count : 7

Abstract : The objective of this project is to study membrane voltage effects on electrogenic proton transport by normal and mutant forms of the hydrogen(H+)ATPase from yeast plasma membranes. This information, coupled with mutant mapping studies, will be used to describe a structurally-distinct proton translocation pathway. The initial goal of this project was to isolate a collection of H+ ATPase-defective mutants. The yeast H+ ATPase is an electrogenic proton pump that plays a vital role in nutrient uptake and intracellular pH regulation. The gene encoding this enzyme, PMA1, was found to be essential for growth. The cellular importance of the H+-ATPase mandates that viable pma1 mutants can only arise from mutations resulting in partially active or conditionally inactive enzymes; past attempts to isolate pma1 mutants were often thwarted by the lack of a suitable selection routine. Recently, we described a positive selection procedure for isolating pma1 mutants from S. cerevisiae based on resistance of UV-treated cells to the aminoglycoside antibiotic hygromycin B. Our working hypothesis was that uptake of this antibiotic was linked to the electrochemical proton gradient and resistant mutants would show defects in the pH gradient and/or the membrane potential. Our first year was spent characterizing the more than 75 mutants isolated and identifying potential transport-defective mutants.

Descriptors :   *PROTONS, *MEMBRANES(BIOLOGY), CODING, ELECTROCHEMISTRY, ENZYMES, GENES, GRADIENTS, HYPOTHESES, INACTIVATION, MAPPING, MUTATIONS, NUTRIENTS, PH FACTOR, RESISTANCE, SELECTION, TRANSPORT, VOLTAGE, YEASTS, PHOSPHATASES, ADENOSINE PHOSPHATES

Subject Categories : Biochemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE