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arXiv · 1602.04470

Binding of the immunomodulatory drug Bz-423 to mitochondrial FoF1-ATP synthase in living cells by FRET acceptor photobleaching

Ilka Starke·Kathryn M. Johnson·Jan Petersen·Peter Graber·Anthony W. Opipari, Jr.·Gary D. Glick·Michael Börsch
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Abstract

Bz-423 is a promising new drug for treatment of autoimmune diseases. This small molecule binds to subunit OSCP of the mitochondrial enzyme FoF1-ATP synthase and modulates its catalytic activities. We investigate the binding of Bz-423 to mitochondria in living cells and how subunit rotation in FoF1-ATP synthase, i.e. the mechanochemical mechanism of this enzyme, is affected by Bz-423. Therefore, the enzyme was marked selectively by genetic fusion with the fluorescent protein EGFP to the C terminus of subunit gamma. Imaging the threedimensional arrangement of mitochondria in living yeast cells was possible at superresolution using structured illumination microscopy, SIM. We measured uptake and binding of a Cy5-labeled Bz-423 derivative to mitochondrial FoF1-ATP synthase in living yeast cells using FRET acceptor photobleaching microscopy. Our data confirmed the binding of Cy5-labeled Bz-423 to the top of the F1 domain of the enzyme in mitochondria of living Saccharomyces cerevisiae cells.

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Ilka Starke, Kathryn M. Johnson, Jan Petersen, Peter Graber, Anthony W. Opipari, Jr., Gary D. Glick, Michael Börsch. 2016-02-14. Binding of the immunomodulatory drug Bz-423 to mitochondrial FoF1-ATP synthase in living cells by FRET acceptor photobleaching. https://doi.org/10.1117/12.2209645

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