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Article Dans Une Revue Nature Communications Année : 2023

Redox driven B12-ligand switch drives CarH photoresponse

Derren Heyes
Linus Johannissen
Laura Jeffreys
Sam Hay
Nigel Scrutton
David Leys

Résumé

Abstract CarH is a coenzyme B 12 -dependent photoreceptor involved in regulating carotenoid biosynthesis. How light-triggered cleavage of the B 12 Co-C bond culminates in CarH tetramer dissociation to initiate transcription remains unclear. Here, a series of crystal structures of the CarH B 12 -binding domain after illumination suggest formation of unforeseen intermediate states prior to tetramer dissociation. Unexpectedly, in the absence of oxygen, Co-C bond cleavage is followed by reorientation of the corrin ring and a switch from a lower to upper histidine-Co ligation, corresponding to a pentacoordinate state. Under aerobic conditions, rapid flash-cooling of crystals prior to deterioration upon illumination confirm a similar B 12 -ligand switch occurs. Removal of the upper His-ligating residue prevents monomer formation upon illumination. Combined with detailed solution spectroscopy and computational studies, these data demonstrate the CarH photoresponse integrates B 12 photo- and redox-chemistry to drive large-scale conformational changes through stepwise Co-ligation changes.

Dates et versions

hal-04304576 , version 1 (24-11-2023)

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Citer

Harshwardhan Poddar, Ronald Rios-Santacruz, Derren Heyes, Muralidharan Shanmugam, Adam Brookfield, et al.. Redox driven B12-ligand switch drives CarH photoresponse. Nature Communications, 2023, 14 (1), pp.5082. ⟨10.1038/s41467-023-40817-6⟩. ⟨hal-04304576⟩
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