title: Synthesis and properties of the red chromophore of the green-to-red photoconvertible fluorescent protein Kaede and its analogs.
abstract: Green fluorescent protein (GFP) and homologous proteins possess a unique pathway of chromophore formation based on autocatalytic modification of their own amino acid residues. Green-to-red photoconvertible fluorescent protein Kaede carries His-Tyr-Gly chromophore-forming triad. Here, we describe synthesis of Kaede red chromophore (2-[(1E)-2-(5-imidazolyl)ethenyl]-4-(p-hydroxybenzylidene)-5-imidazolone) and its analogs that can be potentially formed by natural amino acid residues. Chromophores corresponding to the following tripeptides were obtained: His-Tyr-Gly, Trp-Tyr-Gly, Phe-Trp-Gly, Tyr-Trp-Gly, Asn-Tyr-Gly, Phe-Tyr-Gly, and Tyr-Tyr-Gly. In basic conditions they fluoresced red with relatively high quantum yield (up to 0.017 for Trp-derived compounds). The most red-shifted absorption peak at 595nm was found for the chromophore Trp-Tyr-Gly in basic DMSO. Surprisingly, in basic DMF non-aromatic Asn-derived chromophore Asn-Tyr-Gly demonstrated the most red-shifted emission maximum at 642 nm. Thus, Asn residue may be a promising substituent, which can potentially diversify posttranslational chemistry in GFP-like proteins.
authors.affiliation: Institute of Bioorganic Chemistry, Lab of Molecular Techonologies, Miklukho-Maklaya 16/10, Moscow 117997, Russian Federation.
authors.forename: Ilia V
authors.initials: IV
authors.lastname: Yampolsky
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Kislukhin
authors.forename: Tynchtyk T
authors.initials: TT
authors.lastname: Amatov
authors.forename: Dmitry
authors.initials: D
authors.lastname: Shcherbo
authors.forename: Victor K
authors.initials: VK
authors.lastname: Potapov
authors.forename: Sergey
authors.initials: S
authors.lastname: Lukyanov
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Lukyanov
mesh_terms: D019943:Amino Acid Substitution; D003116:Color; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000138:chemical synthesis* / Q000737:chemistry*; D009842:Oligopeptides; D013057:Spectrum Analysis; D000097573:Red Fluorescent Protein
chemical_list: D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins; D009842:Oligopeptides; D000097573:Red Fluorescent Protein; C513582:Kaede protein, Trachyphyllia geoffroyi