Abstract
We have developed an effective experimental system for the characterization of molecular and structural mobility. It incorporates a modified fluorescence microscope geometry and a variety of analytical techniques to measure effective diffusion coefficients ranging over almost six orders of magnitude, from less than 10(-11) cm2/s to greater than 10(-6) cm2/s. Two principal techniques, fluorescence correlation spectroscopy (FCS) and fluorescence photobleaching recovery (FPR), are employed. In the FPR technique, translational transport rates are measured by monitoring the evolution of a spatial inhomogeneity of fluorescence that is produced photochemically in a microscopic volume by a short burst of intense laser radiation. In contrast, FCS uses laser-induced fluorescence to probe the spontaneous concentration fluctuations in microscopic sample volumes. The kinetics are analyzed by computing time-correlation functions of the stochastic fluctuations of the measured fluorescence intensity. The optical system and digital photocount correlator designed around a dedicated minicomputer are described and discussed. The general power of these techniques is demonstrated with examples from studies conducted on bulk solutions, lipid bilayer membranes, and mammalian cell plasma membranes.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Axelrod D., Koppel D. E., Schlessinger J., Elson E., Webb W. W. Mobility measurement by analysis of fluorescence photobleaching recovery kinetics. Biophys J. 1976 Sep;16(9):1055–1069. doi: 10.1016/S0006-3495(76)85755-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carlson F. D. The application of intensity fluctuation spectroscopy to molecular biology. Annu Rev Biophys Bioeng. 1975;4(00):243–264. doi: 10.1146/annurev.bb.04.060175.001331. [DOI] [PubMed] [Google Scholar]
- Edidin M., Zagyansky Y., Lardner T. J. Measurement of membrane protein lateral diffusion in single cells. Science. 1976 Feb 6;191(4226):466–468. doi: 10.1126/science.1246629. [DOI] [PubMed] [Google Scholar]
- Jacobson K., Wu E., Poste G. Measurement of the translational mobility of concanavalin A in glycerol-saline solutions and on the cell surface by fluorescence recovery after photobleaching. Biochim Biophys Acta. 1976 Apr 16;433(1):215–222. doi: 10.1016/0005-2736(76)90189-9. [DOI] [PubMed] [Google Scholar]
- Koppel D. E. Study of Escherichia coli ribosomes by intensity fluctuation spectroscopy of scattered laser light. Biochemistry. 1974 Jun 18;13(13):2712–2719. doi: 10.1021/bi00710a009. [DOI] [PubMed] [Google Scholar]
- Magde D., Elson E. L., Webb W. W. Fluorescence correlation spectroscopy. II. An experimental realization. Biopolymers. 1974 Jan;13(1):29–61. doi: 10.1002/bip.1974.360130103. [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]
- Schlessinger J., Koppel D. E., Axelrod D., Jacobson K., Webb W. W., Elson E. L. Lateral transport on cell membranes: mobility of concanavalin A receptors on myoblasts. Proc Natl Acad Sci U S A. 1976 Jul;73(7):2409–2413. doi: 10.1073/pnas.73.7.2409. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weissman M., Schindler H., Feher G. Determination of molecular weights by fluctuation spectroscopy: application to DNA. Proc Natl Acad Sci U S A. 1976 Aug;73(8):2776–2780. doi: 10.1073/pnas.73.8.2776. [DOI] [PMC free article] [PubMed] [Google Scholar]