title: A photoswitchable orange-to-far-red fluorescent protein, PSmOrange.
abstract: We report a photoswitchable monomeric Orange (PSmOrange) protein that is initially orange (excitation, 548 nm; emission, 565 nm) but becomes far-red (excitation, 636 nm; emission, 662 nm) after irradiation with blue-green light. Compared to its parental orange proteins, PSmOrange has greater brightness, faster maturation, higher photoconversion contrast and better photostability. The red-shifted spectra of both forms of PSmOrange enable its simultaneous use with cyan-to-green photoswitchable proteins to study four intracellular populations. Photoconverted PSmOrange has, to our knowledge, the most far-red excitation peak of all GFP-like fluorescent proteins, provides diffraction-limited and super-resolution imaging in the far-red light range, is optimally excited with common red lasers, and can be photoconverted subcutaneously in a mouse. PSmOrange photoswitching occurs via a two-step photo-oxidation process, which causes cleavage of the polypeptide backbone. The far-red fluorescence of photoconverted PSmOrange results from a new chromophore containing N-acylimine with a co-planar carbon-oxygen double bond.
authors.affiliation: Department of Anatomy and Structural Biology, and Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, New York, USA.
authors.forename: Oksana M
authors.initials: OM
authors.lastname: Subach
authors.forename: George H
authors.initials: GH
authors.lastname: Patterson
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Ting
authors.forename: Yarong
authors.initials: Y
authors.lastname: Wang
authors.forename: John S
authors.initials: JS
authors.lastname: Condeelis
authors.forename: Vladislav V
authors.initials: VV
authors.lastname: Verkhusha
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D003116:Color; D005260:Female; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry / Q000528:radiation effects; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008027:Light; D008164:Luminescent Proteins / Q000737:chemistry* / Q000528:radiation effects; D051379:Mice; D008969:Molecular Sequence Data
chemical_list: D005456:Fluorescent Dyes; D008164:Luminescent Proteins; C413663:fluorescent protein 583