Structural basis for gene regulation by a B12-dependent photoreceptor
Name
Drennan_Structural basis.pdf
Size
4.69 MB
Format
Adobe PDF
Checksum (MD5)
449888bc5dbea673d033230d2216f762
Author(s)
Fernández-Zapata, Jésus
Polanco, María Carmen
Ortiz-Guerrero, Juan Manuel
Padmanabhan, S.
Elías-Arnanz, Montserrat
Jost, Marco
Chen, Yang-Ting
Drennan, Catherine L.
Kang, Gyung Hoon
Date Issued
September 2015
Journal
Nature
Publisher
Nature Publishing Group
Citation
Jost, Marco et al. “Structural Basis for Gene Regulation by a B12-Dependent Photoreceptor.” Nature 526.7574 (2015): 536–541.
Version
Author's final manuscript
Abstract
Photoreceptor proteins enable organisms to sense and respond to light. The newly discovered CarH-type photoreceptors use a vitamin B[subscript 12] derivative, adenosylcobalamin, as the light-sensing chromophore to mediate light-dependent gene regulation. Here we present crystal structures of Thermus thermophilus CarH in all three relevant states: in the dark, both free and bound to operator DNA, and after light exposure. These structures provide visualizations of how adenosylcobalamin mediates CarH tetramer formation in the dark, how this tetramer binds to the promoter −35 element to repress transcription, and how light exposure leads to a large-scale conformational change that activates transcription. In addition to the remarkable functional repurposing of adenosylcobalamin from an enzyme cofactor to a light sensor, we find that nature also repurposed two independent protein modules in assembling CarH. These results expand the biological role of vitamin B[subscript 12] and provide fundamental insight into a new mode of light-dependent gene regulation.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Massachusetts Institute of Technology. Department of Chemistry
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/nature14950
