Published August 12, 2016 | Version v1
Journal article Open

Structural photoactivation of a full-length bacterial phytochrome

Description

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.

Data availability

All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data related to this paper may be requested from the authors.

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Additional details

Identifiers

DOI
10.1126/sciadv.1600920
Other
oai:uchicago.tind.io:11027

Funding

Swedish Foundation for International Cooperation in Research and Higher Education
European Research Council
Stiftelsen för Strategisk Forskning
Suomen Akatemia
Suomen Kulttuurirahasto
Seventh Framework Programme
IEF-GA- 238 2013-CHE-624864 ANISOPROTEINXRAY
Basic Energy Sciences
DE-AC02-06CH11357
National Institute of General Medical Sciences
1R24GM111072

UChicago Information

Division(s)
Biological Sciences Division
Department(s)
Biochemistry and Molecular Biology