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Publication Abstract from PubMed

Rotation around a specific bond after photoexcitation is central to vision and emerging opportunities in optogenetics, super-resolution microscopy, and photoactive molecular devices. Competing roles for steric and electrostatic effects that govern bond-specific photoisomerization have been widely discussed, the latter originating from chromophore charge transfer upon excitation. We systematically altered the electrostatic properties of the green fluorescent protein chromophore in a photoswitchable variant, Dronpa2, using amber suppression to introduce electron-donating and electron-withdrawing groups to the phenolate ring. Through analysis of the absorption (color), fluorescence quantum yield, and energy barriers to ground- and excited-state isomerization, we evaluate the contributions of sterics and electrostatics quantitatively and demonstrate how electrostatic effects bias the pathway of chromophore photoisomerization, leading to a generalized framework to guide protein design.

Electrostatic control of photoisomerization pathways in proteins.,Romei MG, Lin CY, Mathews II, Boxer SG Science. 2020 Jan 3;367(6473):76-79. doi: 10.1126/science.aax1898. PMID:31896714^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.