Abstract
The precise regulation of protein activity is fundamental to life. The allosteric control of an active site by a remote regulatory binding site is a mechanism of regulation found across protein classes, from enzymes to motors to signaling proteins. We describe a general approach for manipulating allosteric control using synthetic optical switches. Our strategy is exemplified by a ligand-gated ion channel of central importance in neuroscience, the ionotropic glutamate receptor (iGluR). Using structure-based design, we have modified its ubiquitous clamshell-type ligand-binding domain to develop a light-activated channel, which we call LiGluR. An agonist is covalently tethered to the protein through an azobenzene moiety, which functions as the optical switch. The agonist is reversibly presented to the binding site upon photoisomerization, initiating clamshell domain closure and concomitant channel gating. Photoswitching occurs on a millisecond timescale, with channel conductances that reflect the photostationary state of the azobenzene at a given wavelength. Our device has potential uses not only in biology but also in bioelectronics and nanotechnology.
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Acknowledgements
We thank K. Partin for the iGluR6 cDNA and for advice, T. Machen for guidance on calcium imaging and S. Szobota for participation in initial imaging experiments. P.G. was supported by postdoctoral fellowships from the Generalitat de Catalunya (Nanotechnology Program), Ministerio de Educación y Ciencia (Spain) and the Human Frontier Science Program. R.N. was supported by a postdoctoral fellowship from the Japan Society for the Promotion of Science. This work was supported by a Laboratory Directed Research Development Award from the Lawrence Berkeley National Laboratory and by a grant from the Human Frontier Science Program. D.T. thanks Eli Lilly, Astra Zeneca, Glaxo Smith Kline, Amgen and Merck & Co. for Young Investigator Awards.
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Volgraf, M., Gorostiza, P., Numano, R. et al. Allosteric control of an ionotropic glutamate receptor with an optical switch. Nat Chem Biol 2, 47–52 (2006). https://doi.org/10.1038/nchembio756
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DOI: https://doi.org/10.1038/nchembio756
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