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Effects of membrane channel-forming polypeptides on mitochondrial oxidative phosphorylation. A comparison of alamethicin, gramicidin A, melittin and tetraacetyl melittin.

Das, MK and Basu, A and Balaram, P (1985) Effects of membrane channel-forming polypeptides on mitochondrial oxidative phosphorylation. A comparison of alamethicin, gramicidin A, melittin and tetraacetyl melittin. In: Biochemistry International, 11 (3). 357 -363.

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Official URL: http://www.ncbi.nlm.nih.gov/pubmed/2415130

Abstract

Transmembrane channel-forming polypeptides can function as uncouplers of mitochondrial oxidative phosphorylation. The observed effects are dependent on the phosphate ion (Pi) concentration in the medium. At low Pi (2.5 mM) the order of uncoupling efficiencies is gramicidin A much greater than alamethicin greater than tetraacetyl melittin greater than melittin. The remarkably high activity of gramicidin A suggests insertion of preformed channel dimers into the membrane. It is also suggested that lipid phase association of peptides is necessary in the other cases. At Pi = 100 mM inhibitory effects are observed for alamethicin and tetraacetyl melittin. Less pronounced inhibition is seen for melittin, while no such effect is noted for gramicidin A. The site of inhibition is shown to be complex IV, and the differences in the behavior of the peptides are rationalized in terms of channel structures.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Academic Press Aust.
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Depositing User: Ms TV Yashodha
Date Deposited: 20 May 2010 05:02
Last Modified: 19 Sep 2010 06:00
URI: http://eprints.iisc.ac.in/id/eprint/27217

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