Fluorescence evidence for cholesterol regular distribution in phosphatidylcholine and in sphingomyeline lipid bilayers

Parkson L. Chong, Mei Mei Wang, Fang Liu, Khanh Truong, Anthony A. Golsorkhi, Istvan P. Sugar, Rhoderick E. Brown

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Our previous studies indicated that sterols (including cholesterol and dehydroergosterol) can be regularly distributed into hexagonal superlattices in the plane of liquid-crystalline phosphatidylcholine bilayers. It was suggested that regular and irregular regions coexist in the membrane. In the present study, we report supporting evidence for our sterol regular distribution model. We have examined the fractional concentration dependencies of dehydroergosterol (a naturally occurring cholesterol analog) fluorescence intensity and lifetime in various phosphatidylcholine and sphingomyelin bilayers. Fluorescence intensity and lifetime dips have been observed at specific sterol mole fractions. At those mole fractions, the acrylamide quenching rate constant of dehydroergosterol fluorescence reaches a local maximum. Those mole fractions match with the critical sterol mole fractions at which sterol molecules are expected to be regularly distributed into hexagonal superlattices. The results support the idea that the sterols in the regular region are embedded in the bilayer less deep than those in the irregular regions. Furthermore, finding evidence for sterol regular distribution in both phosphatidylcholine and sphingomyelin membranes raises the possibility that sterol regular distribution may occur within phospholipid/cholesterol enriched domains of real biological membranes.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsE.R. Menzel
Pages143-154
Number of pages12
StatePublished - Jan 1 1996
Externally publishedYes
EventFluorescence Detection IV - San Jose, CA, USA
Duration: Feb 1 1996Feb 2 1996

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume2705
ISSN (Print)0277-786X

Other

OtherFluorescence Detection IV
CitySan Jose, CA, USA
Period2/1/962/2/96

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Chong, P. L., Wang, M. M., Liu, F., Truong, K., Golsorkhi, A. A., Sugar, I. P., & Brown, R. E. (1996). Fluorescence evidence for cholesterol regular distribution in phosphatidylcholine and in sphingomyeline lipid bilayers. In E. R. Menzel (Ed.), Proceedings of SPIE - The International Society for Optical Engineering (pp. 143-154). (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 2705).