This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.104.050559v1 88/3/1875    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Deverall, M. A. Articles by Naumann, C. A. Search for Related Content PubMed PubMed Citation Articles by Deverall, M. A. Articles by Naumann, C. A.

Membrane Lateral Mobility Obstructed by Polymer-Tethered Lipids Studied at the Single Molecule Level

M. A. Deverall ^*, E. Gindl , E.-K. Sinner , H. Besir , J. Ruehe , M. J. Saxton  and C. A. Naumann ^*

^* Department of Chemistry, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana; Max-Planck-Institute for Biochemistry, Martinsried, Germany; Institut für Mikrosystemtechnik, Universität Freiburg, Freiburg, Germany; and Department of Biochemistry and Molecular Medicine, University of California, Davis, California

Correspondence: Address reprint requests to Christoph A. Naumann, Dept. of Chemistry, Indiana University-Purdue University Indianapolis (IUPUI), 402 N. Blackford St., Indianapolis, IN, 46202-3274. E-mail: naumann{at}chem.iupui.edu.

Obstructed long-range lateral diffusion of phospholipids (TRITC-DHPE) and membrane proteins (bacteriorhodopsin) in a planar polymer-tethered 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer is studied using wide-field single molecule fluorescence microscopy. The obstacles are well-controlled concentrations of hydrophobic lipid-mimicking dioctadecylamine moieties in the polymer-exposed monolayer of the model membrane. Diffusion of both types of tracer molecules is well described by a percolating system with different percolation thresholds for lipids and proteins. Data analysis using a free area model of obstructed lipid diffusion indicates that phospholipids and tethered lipids interact via hard-core repulsion. A comparison to Monte Carlo lattice calculations reveals that tethered lipids act as immobile obstacles, are randomly distributed, and do not self-assemble into large-scale aggregates for low to moderate tethering concentrations. A procedure is presented to identify anomalous subdiffusion from tracking data at a single time lag. From the analysis of the cumulative distribution function of the square displacements, it was found that TRITC-DHPE and W80i show normal diffusion at lower concentrations of tethered lipids and anomalous diffusion at higher ones. This study may help improve our understanding of how lipids and proteins in biomembranes may be obstructed by very small obstacles comprising only one or very few molecules.

This article has been cited by other articles:

				J. M. Crane and A. S. Verkman Long-Range Nonanomalous Diffusion of Quantum Dot-Labeled Aquaporin-1 Water Channels in the Cell Plasma Membrane Biophys. J., January 15, 2008; 94(2): 702 - 713. [Abstract] [Full Text] [PDF]

				S. Garg, J. Ruhe, K. Ludtke, R. Jordan, and C. A. Naumann Domain Registration in Raft-Mimicking Lipid Mixtures Studied Using Polymer-Tethered Lipid Bilayers Biophys. J., February 15, 2007; 92(4): 1263 - 1270. [Abstract] [Full Text] [PDF]

				V. Kiessling, J. M. Crane, and L. K. Tamm Transbilayer Effects of Raft-Like Lipid Domains in Asymmetric Planar Bilayers Measured by Single Molecule Tracking Biophys. J., November 1, 2006; 91(9): 3313 - 3326. [Abstract] [Full Text] [PDF]

				M. Ming, M. Lu, S. P. Balashov, T. G. Ebrey, Q. Li, and J. Ding pH Dependence of Light-Driven Proton Pumping by an Archaerhodopsin from Tibet: Comparison with Bacteriorhodopsin Biophys. J., May 1, 2006; 90(9): 3322 - 3332. [Abstract] [Full Text] [PDF]

				M. L. Dustin and C. Zhu T cells like a firm molecular handshake PNAS, March 21, 2006; 103(12): 4335 - 4336. [Full Text] [PDF]