title: Exploring color tuning strategies in red fluorescent proteins.
abstract: Red-emitting fluorescent proteins (RFPs) with fluorescence emission above 600 nm are advantageous for cell and tissue imaging applications for various reasons. Fluorescence from an RFP is well separated from cellular autofluorescence, which is in the green region of the spectrum, and red light is scattered less, which allows thicker specimens to be imaged. Moreover, the phototoxic response of cells is lower for red than blue or green light exposure. Further red-shifted FP variants can be obtained by genetic modifications causing an extension of the conjugated π-electron system of the chromophore, or by placing amino acids near the chromophore that stabilize its excited state or destabilize its ground state. We have selected the tetrameric RFP eqFP611 from Entacmaea quadricolor as a lead structure and discuss several rational design trials to generate RFP variants with improved photochemical properties.
authors.affiliation: Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1, 76131 Karlsruhe, Germany. uli@illinois.edu.
authors.forename: Anika
authors.initials: A
authors.lastname: Hense
authors.forename: Karin
authors.initials: K
authors.lastname: Nienhaus
authors.forename: G Ulrich
authors.initials: GU
authors.lastname: Nienhaus
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003116:Color; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D008164:Luminescent Proteins / Q000737:chemistry* / Q000235:genetics* / Q000633:toxicity; D055668:Photochemical Processes; D011487:Protein Conformation; D015202:Protein Engineering / Q000379:methods; D017510:Protein Folding; D055550:Protein Stability; D012615:Sea Anemones; D016415:Sequence Alignment; D000097573:Red Fluorescent Protein
chemical_list: D008164:Luminescent Proteins; D000097573:Red Fluorescent Protein