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Proceedings Paper

Diffusion properties of single FoF1-ATP synthases in a living bacterium unraveled by localization microscopy
Author(s): Marc Renz; Torsten Rendler; Michael Börsch
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Paper Abstract

FoF1-ATP synthases in Escherichia coli (E. coli) bacteria are membrane-bound enzymes which use an internal protondriven rotary double motor to catalyze the synthesis of adenosine triphosphate (ATP). According to the 'chemiosmotic hypothesis', a series of proton pumps generate the necessary pH difference plus an electric potential across the bacterial plasma membrane. These proton pumps are redox-coupled membrane enzymes which are possibly organized in supercomplexes, as shown for the related enzymes in the mitochondrial inner membrane. We report diffusion measurements of single fluorescent FoF1-ATP synthases in living E. coli by localization microscopy and single enzyme tracking to distinguish a monomeric enzyme from a supercomplex-associated form in the bacterial membrane. For quantitative mean square displacement (MSD) analysis, the limited size of the observation area in the membrane with a significant membrane curvature had to be considered. The E. coli cells had a diameter of about 500 nm and a length of about 2 to 3 μm. Because the surface coordinate system yielded different localization precision, we applied a sliding observation window approach to obtain the diffusion coefficient D = 0.072 μm2/s of FoF1-ATP synthase in living E. coli cells.

Paper Details

Date Published: 9 February 2012
PDF: 11 pages
Proc. SPIE 8225, Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues X, 822513 (9 February 2012); doi: 10.1117/12.907089
Show Author Affiliations
Marc Renz, Univ. of Stuttgart (Germany)
Jena Univ. Hospital (Germany)
Torsten Rendler, Univ. of Stuttgart (Germany)
Michael Börsch, Univ. of Stuttgart (Germany)
Jena Univ. Hospital (Germany)

Published in SPIE Proceedings Vol. 8225:
Imaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues X
Daniel L. Farkas; Dan V. Nicolau; Robert C. Leif, Editor(s)

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