title: Structural photoactivation of a full-length bacterial phytochrome.
abstract: Phytochromes are light sensor proteins found in plants, bacteria, and fungi. They function by converting a photon absorption event into a conformational signal that propagates from the chromophore through the entire protein. However, the structure of the photoactivated state and the conformational changes that lead to it are not known. We report time-resolved x-ray scattering of the full-length phytochrome from Deinococcus radiodurans on micro- and millisecond time scales. We identify a twist of the histidine kinase output domains with respect to the chromophore-binding domains as the dominant change between the photoactivated and resting states. The time-resolved data further show that the structural changes up to the microsecond time scales are small and localized in the chromophore-binding domains. The global structural change occurs within a few milliseconds, coinciding with the formation of the spectroscopic meta-Rc state. Our findings establish key elements of the signaling mechanism of full-length bacterial phytochromes.
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Björling
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Oskar
authors.initials: O
authors.lastname: Berntsson
authors.affiliation: University of Jyväskylä, 40014 Jyväskylä, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Lehtivuori
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.; University of Jyväskylä, 40014 Jyväskylä, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Takala
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Ashley J
authors.identifier: 0000-0002-9468-7442
authors.initials: AJ
authors.lastname: Hughes
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Matthijs
authors.identifier: 0000-0003-3853-123X
authors.initials: M
authors.lastname: Panman
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Hoernke
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Stephan
authors.initials: S
authors.lastname: Niebling
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Léocadie
authors.identifier: 0000-0002-0500-820X
authors.initials: L
authors.lastname: Henry
authors.affiliation: University of Chicago, Chicago, IL 60637, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Henning
authors.affiliation: University of Chicago, Chicago, IL 60637, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Kosheleva
authors.affiliation: Tampere University of Technology, 33720 Tampere, Finland.
authors.forename: Vladimir
authors.identifier: 0000-0002-3076-8948
authors.initials: V
authors.lastname: Chukharev
authors.affiliation: Tampere University of Technology, 33720 Tampere, Finland.
authors.forename: Nikolai V
authors.identifier: 0000-0002-8504-2335
authors.initials: NV
authors.lastname: Tkachenko
authors.affiliation: Paul Scherrer Institut, Villigen, 5232 Villigen PSI, Switzerland.
authors.forename: Andreas
authors.identifier: 0000-0002-0489-609X
authors.initials: A
authors.lastname: Menzel
authors.affiliation: European Synchrotron Radiation Facility, 38000 Grenoble, France.
authors.forename: Gemma
authors.initials: G
authors.lastname: Newby
authors.affiliation: European Synchrotron Radiation Facility, 38000 Grenoble, France.
authors.forename: Dmitry
authors.initials: D
authors.lastname: Khakhulin
authors.affiliation: European Synchrotron Radiation Facility, 38000 Grenoble, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Wulff
authors.affiliation: University of Jyväskylä, 40014 Jyväskylä, Finland.
authors.forename: Janne A
authors.initials: JA
authors.lastname: Ihalainen
authors.affiliation: University of Gothenburg, 40530 Gothenburg, Sweden.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Westenhoff
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D020283:Photoreceptors, Microbial / Q000737:chemistry* / Q000378:metabolism; D010834:Phytochrome / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; D010834:Phytochrome