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FLUORENYL FATTY-ACIDS AS FLUORESCENT-PROBES FOR DEPTH-DEPENDENT ANALYSIS OF ARTIFICIAL AND NATURAL MEMBRANES

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Title FLUORENYL FATTY-ACIDS AS FLUORESCENT-PROBES FOR DEPTH-DEPENDENT ANALYSIS OF ARTIFICIAL AND NATURAL MEMBRANES
 
Creator LALA, AK
KOPPAKA, V
 
Subject tryptophan fluorescence
labeled phospholipids
hydrophobic core
lipid bilayer
gel phase
quenchers
calcium
 
Description The main objective of depth-dependent fluorescent probes is to provide information at a distinct position in the membrane hydrophobic core. We report here a series of fluorenyl fatty acids which can probe both artificial and natural membranes at different depths. Long-chain acids (C4, C6, and C8) are attached to fluorene chromophore on one side, and a hydrophobic tail (C4) is attached on the other side, so that on incorporation in membranes the carboxyl end of the molecule is oriented toward the membrane-water interface and the hydrophobic tail points toward the membrane interior. These acids can be readily partitioned into membranes. The disposition of these fluorenyl fatty acids in membranes was studied by fluorescence quenching using iodide as a water-soluble and 9,10-dibromostearic acid as a lipid-soluble quencher. The results obtained indicate that attachment of a hydrophobic tail is essential for effective alignment of depth-dependent fluorescent probes. The length of the hydrophobic tail was varied and an n-butyl chain was found to be most effective. In all cases, the compounds with a hydrophobic tail were found to be probing the membrane deeper than their counterparts with no hydrophobic tail. Further, the compounds with hydrophobic tails were more strongly immobilized in the membrane as indicated by fluorescence polarization studies. However, the effect of such a tail varied with membrane type. Thus in artificial membranes an n-butyl chain was found to be extremely important for effective monitoring by shallow probes like 4-(2'-fluorenyl)butyric acid, whereas in erythrocyte ghost membranes the same n-butyl tail was found to be more desirable for deeper probes like 8-(2'-fluorenyl)octanoic acid. The general molecular design strategy reported here can be extended to other fluorescent probes and photoactivable reagents for depth-dependent analysis of membranes.
 
Publisher AMER CHEMICAL SOC
 
Date 2011-07-14T05:12:49Z
2011-12-26T12:48:12Z
2011-12-27T05:46:16Z
2011-07-14T05:12:49Z
2011-12-26T12:48:12Z
2011-12-27T05:46:16Z
1992
 
Type Article
 
Identifier BIOCHEMISTRY, 31(24), 5586-5593
0006-2960
http://dx.doi.org/10.1021/bi00139a023
http://dspace.library.iitb.ac.in/xmlui/handle/10054/3863
http://hdl.handle.net/10054/3863
 
Language en