title: Dynamic Nuclear Polarization Provides New Insights into Chromophore Structure in Phytochrome Photoreceptors.
abstract: Phytochromes are red/far-red photochromic photoreceptors acting as master regulators of development in higher plants, thereby controlling transcription of about 20 % of their genes. Light-induced isomerization of the bilin chromophore leads to large rearrangements in protein structure, whereby the role of protonation dynamics and charge distribution is of particular interest. To help unravel the inherent mechanisms, we present two-dimensional dynamic nuclear polarization (DNP) enhanced solid-state magic-angle spinning (MAS) NMR spectra of the functional sensory module of the cyanobacterial phytochrome Cph1. To this end, the pyrrole ring nitrogen signals were assigned unequivocally, enabling us to locate the positive charge of the phycocyanobilin (PCB) chromophore. To help analyze proton exchange pathways, the proximity of PCB ring nitrogen atoms and functionally relevant H2O molecules was also determined. Our study demonstrates the value of DNP in biological solid-state MAS NMR spectroscopy.
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), NMR-supported Structural Biology, Robert-Rössle-Str. 10, 13125, Berlin, Germany.|Freie Universität Berlin, Fachbereich BCP, Takustr. 3, 14195, Berlin, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Stöppler
authors.affiliation: Universität Leipzig, Institut für Analytische Chemie, Linnéstr. 3, 04103, Leipzig, Germany.
authors.forename: Chen
authors.initials: C
authors.lastname: Song
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), NMR-supported Structural Biology, Robert-Rössle-Str. 10, 13125, Berlin, Germany.
authors.forename: Barth-Jan
authors.initials: BJ
authors.lastname: van Rossum
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), NMR-supported Structural Biology, Robert-Rössle-Str. 10, 13125, Berlin, Germany.|Freie Universität Berlin, Fachbereich BCP, Takustr. 3, 14195, Berlin, Germany.
authors.forename: Michel-Andreas
authors.initials: MA
authors.lastname: Geiger
authors.affiliation: Justus-Liebig-Universität Gießen, Institut für Pflanzenphysiologie, Senckenbergstr. 3, 35390, Gießen, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Lang
authors.affiliation: Technische Universität Berlin, Institut für Chemie, Straße des 17. Juni 135, 10623, Berlin, Germany.
authors.forename: Maria-Andrea
authors.initials: MA
authors.lastname: Mroginski
authors.affiliation: University of Iceland, Department of Chemistry, Dunhaga 3, 107, Reykjavik, Iceland.
authors.forename: Anil Pandurang
authors.initials: AP
authors.lastname: Jagtap
authors.affiliation: University of Iceland, Department of Chemistry, Dunhaga 3, 107, Reykjavik, Iceland.
authors.forename: Snorri Th
authors.initials: ST
authors.lastname: Sigurdsson
authors.affiliation: Universität Leipzig, Institut für Analytische Chemie, Linnéstr. 3, 04103, Leipzig, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Matysik
authors.affiliation: Justus-Liebig-Universität Gießen, Institut für Pflanzenphysiologie, Senckenbergstr. 3, 35390, Gießen, Germany.
authors.forename: Jon
authors.initials: J
authors.lastname: Hughes
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), NMR-supported Structural Biology, Robert-Rössle-Str. 10, 13125, Berlin, Germany.|Freie Universität Berlin, Fachbereich BCP, Takustr. 3, 14195, Berlin, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Oschkinat
mesh_terms: D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D055519:Photoreceptors, Plant / Q000737:chemistry*; D010834:Phytochrome / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D055519:Photoreceptors, Plant; D010834:Phytochrome
keywords: NMR spectroscopy; chromophores; dynamic nuclear polarization; photochemistry; phytochromes