Abstract
A burst of linearly polarized laser radiation incident on a spherical lipid vesicle, liposome, or biological cell can produce a well-defined nonuniform distribution of membrane-bound fluorescent molecules, provided the absorption transition dipole moment of the fluorescent label has a nonrandom orientation relative to the membrane surface and can be photobleached by the laser radiation. The return (recovery) of fluorescent membrane-bound molecules to a uniform distribution can be monitored using the same polarized radiation source. Under appropriate conditions this recovery is characterized by a single exponential time constant tau. This time constant is related to the radius R of the vesicle and the lateral diffusion coefficient D of the fluorescent membrane-bound molecules by the equation R2 = 6D tau. In the case of vesicle membranes this result is not limited by diffraction and so should be applicable to vesicles whose radii are less than the wavelength of light. The above considerations are illustrated by the polarized light photobleaching-recovery of lipid vesicles containing a fluorescent lipid, N-4-nitro-benzo-2-oxa,1,3-diazole l-alpha-dimyristoylphosphatidylethanolamine (NBD-DMPE).
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- Axelrod D. Carbocyanine dye orientation in red cell membrane studied by microscopic fluorescence polarization. Biophys J. 1979 Jun;26(3):557–573. doi: 10.1016/S0006-3495(79)85271-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cherry R. J. Rotational and lateral diffusion of membrane proteins. Biochim Biophys Acta. 1979 Dec 20;559(4):289–327. doi: 10.1016/0304-4157(79)90009-1. [DOI] [PubMed] [Google Scholar]
- Peters R., Peters J., Tews K. H., Bähr W. A microfluorimetric study of translational diffusion in erythrocyte membranes. Biochim Biophys Acta. 1974 Nov 15;367(3):282–294. doi: 10.1016/0005-2736(74)90085-6. [DOI] [PubMed] [Google Scholar]
- Rubenstein J. L., Smith B. A., McConnell H. M. Lateral diffusion in binary mixtures of cholesterol and phosphatidylcholines. Proc Natl Acad Sci U S A. 1979 Jan;76(1):15–18. doi: 10.1073/pnas.76.1.15. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith B. A., Clark W. R., McConnell H. M. Anisotropic molecular motion on cell surfaces. Proc Natl Acad Sci U S A. 1979 Nov;76(11):5641–5644. doi: 10.1073/pnas.76.11.5641. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith B. A., McConnell H. M. Determination of molecular motion in membranes using periodic pattern photobleaching. Proc Natl Acad Sci U S A. 1978 Jun;75(6):2759–2763. doi: 10.1073/pnas.75.6.2759. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith L. M., Parce J. W., Smith B. A., McConnell H. M. Antibodies bound to lipid haptens in model membranes diffuse as rapidly as the lipids themselves. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4177–4179. doi: 10.1073/pnas.76.9.4177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith L. M., Smith B. A., McConnell H. M. Lateral diffusion of M-13 coat protein in model membranes. Biochemistry. 1979 May 29;18(11):2256–2259. doi: 10.1021/bi00578a019. [DOI] [PubMed] [Google Scholar]
- Yguerabide J., Stryer L. Fluorescence spectroscopy of an oriented model membrane. Proc Natl Acad Sci U S A. 1971 Jun;68(6):1217–1221. doi: 10.1073/pnas.68.6.1217. [DOI] [PMC free article] [PubMed] [Google Scholar]