title: Monomeric Garnet, a far-red fluorescent protein for live-cell STED imaging.
abstract: The advancement of far-red emitting variants of the green fluorescent protein (GFP) is crucially important for imaging live cells, tissues and organisms. Despite notable efforts, far-red marker proteins still need further optimization to match the performance of their green counterparts. Here we present mGarnet, a robust monomeric marker protein with far-red fluorescence peaking at 670 nm. Thanks to its large extinction coefficient of 95,000 M(-1)cm(-1), mGarnet can be efficiently excited with 640-nm light on the red edge of its 598-nm excitation band. A large Stokes shift allows essentially the entire fluorescence emission to be collected even with 640-nm excitation, counterbalancing the lower fluorescence quantum yield of mGarnet, 9.1%, that is typical of far-red FPs. We demonstrate an excellent performance as a live-cell fusion marker in STED microscopy, using 640 nm excitation and 780 nm depletion wavelengths.
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Hense
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Prunsche
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.|Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishitsuka
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Nienhaus
authors.affiliation: Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany.|Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.|Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana IL 61801, USA.
authors.forename: G Ulrich
authors.initials: GU
authors.lastname: Nienhaus
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D015870:Gene Expression; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D057054:Molecular Imaging / Q000379:methods*; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein