Photopharmacology has attracted research attention as an ew tool for achievingo ptical control of biomolecules, following the methods of caged compoundsa nd optogenetics. We have developed an efficient photopharmacological inhibitor-azoMTX-for Escherichia coli dihydrofolate reductase (eDHFR) by replacing some atoms of the originall igand, methotrexate, to achievep hotoisomerization properties. This fine molecular design enabled quick structural conversion between the active "bent" Z isomer of azoMTX and the inactive" extended" E isomer,a nd this property afforded quantitative control over the enzyme activity,d epending on the wavelength of irradiating light applied. Real-time photoreversible control over enzyme activity was also achieved.

Selective inhibitors of Escherichia coli dihydrofolate reductase (eDHFR) are crucial chemical biology tools that have widespread clinical applications. We developed a set of eDHFR-selective photoswitchable inhibitors by derivatizing the structure of our previously reported methotrexate (MTX) azolog, azoMTX. Substitution of the skeletal p-phenylene group of azoMTX with bulky bis-alkylated arylazopyrazole moieties significantly increased its selectivity toward eDHFR over human DHFR. Owing to the physical properties of arylazopyrazoles, the new ligands exhibited nearly complete Z-to-E photoconversion and high thermostability of Z-isomers. In addition, real-time photoreversible control of eDHFR activity was achieved by alternatively switching the illumination light wavelengths.

Artificial control of intracellular protein dynamics with high precision provides deep insight into complicated biomolecular networks. Optogenetics and caged compound-based chemically induced dimerization (CID) systems are emerging as tools for spatiotemporally regulating intracellular protein dynamics. However, both technologies face several challenges for accurate control such as the duration of activation, deactivation rate, and repetition cycles. Herein, we report a photochromic CID system that employs the photoisomerization of a ligand so that both association and dissociation are controlled by light, enabling quick, repetitive, and quantitative regulation of the target protein localization upon violet and green light illumination. We also demonstrated the usability of the photochromic CID system as a potential tool to finely manipulate intracellular protein dynamics to study diverse cellular processes. Utilizing this system to manipulate PINK1/Parkin-mediated mitophagy, we showed that PINK1 recruitment to the mitochondria can promote Parkin recruitment to proceed with mitophagy.

Artificial control of intracellular protein dynamics with high precision provides deep insight into complicated biomolecular networks. Optogenetics and caged compound-based chemically induced dimerization (CID) systems are emerging as tools for spatiotemporally regulating intracellular protein dynamics. However, both technologies face several challenges for accurate control such as the duration of activation, deactivation rate, and repetition cycles. Herein, we report a photochromic CID system that employs the photoisomerization of a ligand so that both association and dissociation are controlled by light, enabling quick, repetitive, and quantitative regulation of the target protein localization upon violet and green light illumination. We also demonstrated the usability of the photochromic CID system as a potential tool to finely manipulate intracellular protein dynamics to study diverse cellular processes. Utilizing this system to manipulate PINK1/Parkin-mediated mitophagy, we showed that PINK1 recruitment to the mitochondria can promote Parkin recruitment to proceed with mitophagy.