Static and dynamic studies of the potential-sensitive membrane probe RH421 in dimyristoylphosphatidylcholine vesicles.
Biochim Biophys Acta
; 1153(2): 203-12, 1993 Dec 12.
Article
in En
| MEDLINE
| ID: mdl-8274489
ABSTRACT
The dynamics of the potential-sensitive styryl dye RH421 in dimyristoylphosphatidylcholine vesicles have been investigated above and below the main phase transition temperature using iodine-laser temperature-jump relaxation spectrophotometry and time-resolved fluorescence lifetime measurements. Equilibrium fluorescence titrations have shown that the affinity of the dye for the membrane is much higher in the liquid-crystalline state than in the gel state. The interaction can be described by either a partition or a binding model and a theory is presented providing a relation between these two approaches. In the liquid-crystalline state bound dye exhibits steady-state fluorescence relaxation processes in the submicrosecond and millisecond time range following a temperature jump. Time-resolved fluorescence measurements show a variation in the fluorescence lifetime across the emission spectrum, suggesting an excited-state process occurring on the subnanosecond time scale. These processes are most likely related to dye and/or lipid reorientation following the temperature jump or excitation pulse. Temperature-dependent changes in the fluorescence excitation spectrum of bound dye suggest that the dye exists in at least two different sites within the membrane.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pyridinium Compounds
/
Styrenes
/
Dimyristoylphosphatidylcholine
/
Fluorescent Dyes
/
Membranes, Artificial
Type of study:
Diagnostic_studies
Language:
En
Journal:
Biochim Biophys Acta
Year:
1993
Type:
Article
Affiliation country:
Germany