title: Selective photoinactivation of protein function through environment-sensitive switching of singlet oxygen generation by photosensitizer.
abstract: Chromophore-assisted light inactivation is a promising technique to inactivate selected proteins with high spatial and temporal resolution in living cells, but its use has been limited because of the lack of a methodology to prevent nonspecific photodamage in the cell owing to reactive oxygen species generated by the photosensitizer. Here we present a design strategy for photosensitizers with an environment-sensitive off/on switch for singlet oxygen ((1)O(2)) generation, which is switched on by binding to the target, to improve the specificity of protein photoinactivation. (1)O(2) generation in the unbound state is quenched by photoinduced electron transfer, whereas (1)O(2) generation can occur in the hydrophobic environment provided by the target protein, after specific binding. Inositol 1,4,5-trisphosphate receptor, which has been suggested to have a hydrophobic pocket around the ligand binding site, was specifically inactivated by an environment-sensitive photosensitizer-conjugated inositol 1,4,5-trisphosphate receptor ligand without (1)O(2) generation in the cytosol of the target cells, despite light illumination, demonstrating the potential of environment-sensitive photosensitizers to allow high-resolution control of generation of reactive oxygen species in the cell.
authors.affiliation: Graduate School of Pharmaceutical Sciences and Department of Pharmacology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Yogo
authors.forename: Yasuteru
authors.initials: Y
authors.lastname: Urano
authors.forename: Akiko
authors.initials: A
authors.lastname: Mizushima
authors.forename: Hisato
authors.initials: H
authors.lastname: Sunahara
authors.forename: Takanari
authors.initials: T
authors.lastname: Inoue
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hirose
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Iino
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kikuchi
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Nagano
mesh_terms: D000818:Animals; D001895:Boron / Q000737:chemistry; D001896:Boron Compounds / Q000494:pharmacology; D002460:Cell Line; D002645:Chickens; D003600:Cytosol / Q000378:metabolism; D005456:Fluorescent Dyes / Q000494:pharmacology*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000737:chemistry; D008027:Light; D008954:Models, Biological; D010100:Oxygen / Q000737:chemistry; D010777:Photochemistry / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011162:Porphobilinogen / Q000031:analogs & derivatives / Q000737:chemistry; D011485:Protein Binding; D026082:Singlet Oxygen
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D005456:Fluorescent Dyes; D053496:Inositol 1,4,5-Trisphosphate Receptors; D017319:Photosensitizing Agents; C507544:dipyrromethene; D026082:Singlet Oxygen; D011162:Porphobilinogen; D001895:Boron; D010100:Oxygen