Document Detail


Effect of dipole modifiers on the kinetics of sensitized photoinactivation of gramicidin channels in bilayer lipid membranes.
MedLine Citation:
PMID:  10661474     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Photodynamic inactivation of gramicidin channels in bilayer lipid membranes induced by single flashes of the visible light in the presence of phthalocyanine has been studied. The kinetic curves of the flash-induced decrease in the gramicidin-mediated electric current are used for determination of the rate constants of formation and termination of gramicidin channels in terms of the channel dimer model. It is revealed that the kinetics of the sensitized photoinactivation of gramicidin in the membrane is altered by agents which modify the dipole potential drop at the membrane-water interface. Addition of phloretin, which is known to decrease the dipole potential drop, slows down the kinetics, whereas the addition of RH421 or 6-ketocholestanol, which increase the dipole potential drop, accelerates the kinetics. It is shown that the photoinactivation kinetics is also slowed down upon the addition of the thyroid hormone L-thyronine, which reduces the dipole potential drop similar to phloretin, as it was found earlier (M. V. Tsybulskaya, Yu. N. Antonenko, A. E. Tropsha, and L. S. Yaguzhinsky, Biofizika 29:801-805 (1984) (in Russian)). It is demonstrated that the changes in the dissociation rate constant of gramicidin dimers under the action of different dipole modifiers correlate with the changes in the dipole potential drop. It is concluded that the process of the gramicidin channel termination corresponding to the dimer dissociation is sensitive to the dipole potential drop. This conclusion is supported by the data on the effect of dipole modifiers on the lifetime of single gramicidin channels.
Authors:
Y N Antonenko; T I Rokitskaya; E A Kotova
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Membrane & cell biology     Volume:  13     ISSN:  1023-6597     ISO Abbreviation:  Membr Cell Biol     Publication Date:  1999  
Date Detail:
Created Date:  2000-03-10     Completed Date:  2000-03-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9517472     Medline TA:  Membr Cell Biol     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  111-20     Citation Subset:  IM    
Affiliation:
Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University. anton@mem.genebee.msu.su
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MeSH Terms
Descriptor/Qualifier:
Gramicidin / metabolism*
Indoles
Ketocholesterols / metabolism
Kinetics
Lipid Bilayers / metabolism*
Phloretin / metabolism
Phosphatidylcholines
Pyridinium Compounds / metabolism
Radiation-Sensitizing Agents
Styrenes / metabolism
Thyronines / metabolism
Chemical
Reg. No./Substance:
0/Indoles; 0/Ketocholesterols; 0/Lipid Bilayers; 0/Phosphatidylcholines; 0/Pyridinium Compounds; 0/Radiation-Sensitizing Agents; 0/Styrenes; 0/Thyronines; 107610-19-5/RH 421; 1405-97-6/Gramicidin; 32448-32-1/1,2-diphytanoylphosphatidylcholine; 574-93-6/phthalocyanine; 60-82-2/Phloretin; 70223-10-8/6-ketocholestanol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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