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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., 2003BB13). 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., 2002BB20; Kottke et al., 2003BB25), in which this cysteine moves ∼1.5 Å closer to the FMN-C(4a) for adduct formation (Fedorov et al., 2003BB13). Thio-adduct formation then triggers rearrangements throughout the whole LOV domain (Gotthard et al., 2023BB17).

IUCrJ
Volume 11| Part 5| September 2024| Pages 749-761
ISSN: 2052-2525
https://doi.org/10.1107/S2052252524005591