title: Structure of a LOV protein in apo-state and implications for construction of LOV-based optical tools.
abstract: Unique features of Light-Oxygen-Voltage (LOV) proteins like relatively small size (~12-19 kDa), inherent modularity, highly-tunable photocycle and oxygen-independent fluorescence have lately been exploited for the generation of optical tools. Structures of LOV domains reported so far contain a flavin chromophore per protein molecule. Here we report two new findings on the short LOV protein W619_1-LOV from Pseudomonas putida. First, the apo-state crystal structure of W619_1-LOV at 2.5 Å resolution reveals conformational rearrangements in the secondary structure elements lining the chromophore pocket including elongation of the Fα helix, shortening of the Eα-Fα loop and partial unfolding of the Eα helix. Second, the apo W619_1-LOV protein binds both natural and structurally modified flavin chromophores. Remarkably different photophysical and photochemical properties of W619_1-LOV bound to 7-methyl-8-chloro-riboflavin (8-Cl-RF) and lumichrome imply application of these variants as novel optical tools as they offer advantages such as no adduct state formation, and a broader choice of wavelengths for in vitro studies.
authors.affiliation: Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Arinkin
authors.affiliation: Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Granzin
authors.affiliation: Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Röllen
authors.affiliation: Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Krauss
authors.affiliation: Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany.|Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, D-52426, Jülich, Germany.
authors.forename: Karl-Erich
authors.initials: KE
authors.lastname: Jaeger
authors.affiliation: Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.|Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, D-40225, Düsseldorf, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Willbold
authors.affiliation: Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Renu
authors.initials: R
authors.lastname: Batra-Safferling
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D005486:Flavin Mononucleotide / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D016958:Pseudomonas putida / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013050:Spectrometry, Fluorescence
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D005486:Flavin Mononucleotide