Fixed-target pump–probe SFX: eliminating the scourge of light contamination

Gotthard, G.; Flores-Ibarra, A.; Carrillo, M.; Kepa, M.W.; Mason, T.J.; Stegmann, D.P.; Olasz, B.; Pachota, M.; Dworkowski, F.; Ozerov, D.; Pedrini, B.F.; Padeste, C.; Beale, J.H.; Nogly, P.

doi:10.1107/S2052252524005591

Figure 3
Thioadduct formation between CrLOV1 and its FMN cofactor upon illumination. Crystal structures of the C. reinhardtii LOV1 domain in light and dark stationary states present two conformations of the binding-site cysteine (Cys57) (Fedorov et al., 2003

). Blue-light absorption causes the formation of a covalent bond between the flavin C(4a) and the thiol of Cys57 within 10 µs. The reaction proceeds through an excited flavin singlet to a triplet state that then decays monotonically to the adduct (Holzer et al., 2002

; Kottke et al., 2003

), in which this cysteine moves ∼1.5 Å closer to the FMN-C(4a) for adduct formation (Fedorov et al., 2003

). Thio-adduct formation then triggers rearrangements throughout the whole LOV domain (Gotthard et al., 2023

IUCrJ

Volume 11| Part 5| September 2024|

ISSN: 2052-2525

https://doi.org/10.1107/S2052252524005591

PHYSICS | FELS

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