title: In Situ Formation of an Azo Bridge on Proteins Controllable by Visible Light.
abstract: Optical modulation of proteins provides superior spatiotemporal resolution for understanding biological processes, and photoswitches built on light-sensitive proteins have been significantly advancing neuronal and cellular studies. Small molecule photoswitches could complement protein-based switches by mitigating potential interference and affording high specificity for modulation sites. However, genetic encodability and responsiveness to nonultraviolet light, two desired properties possessed by protein photoswitches, are challenging to be engineered into small molecule photoswitches. Here we developed a small molecule photoswitch that can be genetically installed onto proteins in situ and controlled by visible light. A pentafluoro azobenzene-based photoswitchable click amino acid (F-PSCaa) was designed to isomerize in response to visible light. After genetic incorporation into proteins via the expansion of the genetic code, F-PSCaa reacts with a nearby cysteine within the protein generating an azo bridge in situ. The resultant bridge is switchable by visible light and allows conformation and binding of CaM to be regulated by such light. This photoswitch should prove valuable in optobiology for its minimal interference, site flexibility, genetic encodability, and response to the more biocompatible visible light.
authors: Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California San Francisco , San Francisco, California 94158, United States.
authors: Christian
authors: C
authors: Hoppmann
authors: Structural Biology Laboratory, Qualcomm Institute, University of California San Diego , San Diego, California 92093, United States.
authors: Innokentiy
authors: I
authors: Maslennikov
authors: Structural Biology Laboratory, Qualcomm Institute, University of California San Diego , San Diego, California 92093, United States.
authors: Senyon
authors: S
authors: Choe
authors: Department of Pharmaceutical Chemistry and the Cardiovascular Research Institute, University of California San Francisco , San Francisco, California 94158, United States.
authors: Lei
authors: L
authors: Wang
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry*; D008027:Light; D008958:Models, Molecular; D062308:Optogenetics / Q000379:methods*; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry* / Q000235:genetics*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D001391:Azo Compounds; D011506:Proteins; C009850:azobenzene