5C8D

Crystal structure of full-length Thermus thermophilus CarH bound to adenosylcobalamin (dark state)

5C8D の概要

• エントリーDOI: 10.2210/pdb5c8d/pdb
• 関連するPDBエントリー: 5C8A 5C8E 5C8F
• 分子名称: Light-dependent transcriptional regulator CarH, COBALAMIN, 5'-DEOXYADENOSINE (3 entities in total)
• 機能のキーワード: transcription factor, light sensor, adenosylcobalamin-binding, dna-binding, transcriptional regulator
• 由来する生物種: Thermus thermophilus (strain HB27 / ATCC BAA-163 / DSM 7039)
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 279238.78

構造登録者

Jost, M.,Drennan, C.L. (登録日: 2015-06-25, 公開日: 2015-09-30, 最終更新日: 2026-03-04)

主引用文献

Jost, M.,Fernandez-Zapata, J.,Polanco, M.C.,Ortiz-Guerrero, J.M.,Chen, P.Y.,Kang, G.,Padmanabhan, S.,Elias-Arnanz, M.,Drennan, C.L.
Structural basis for gene regulation by a B12-dependent photoreceptor.
Nature, 526:536-541, 2015

PubMed Abstract: Photoreceptor proteins enable organisms to sense and respond to light. The newly discovered CarH-type photoreceptors use a vitamin B12 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 B12 and provide fundamental insight into a new mode of light-dependent gene regulation.

PubMed: 26416754
DOI: 10.1038/nature14950

実験手法

X-RAY DIFFRACTION (2.8 Å)