Redox-State-Dependent Structural Changes within a Prokaryotic 6–4 Photolyase
Journal
Journal of the American Chemical Society
Journal Volume
147
Journal Issue
19
Start Page
16084
End Page
16098
ISSN
0002-7863
1520-5126
Date Issued
2025-04-29
Author(s)
Wang, Po-Hsun
Hosokawa, Yuhei
C Soares, Jessica
Emmerich, Hans-Joachim
Fuchs, Valeri
Caramello, Nicolas
Engilberge, Sylvain
Bologna, Andrea
Rosner, Christian Joshua
Nakamura, Mai
Watad, Mohamed
Luo, Fangjia
Owada, Shigeki
Tosha, Takehiko
Kang, Jungmin
Tono, Kensuke
Bessho, Yoshitaka
Nango, Eriko
Pierik, Antonio J.
Royant, Antoine
Tsai, Ming-Daw
Yamamoto, Junpei
Essen, Lars-Oliver
Abstract
Photolyases repair UV damage to DNA by using absorbed blue light. Within the photolyase/cryptochrome superfamily (PCSf), a major subgroup consists of prokaryotic (6-4) photolyases. These enzymes rely on flavin adenine dinucleotide (FAD) as a catalytic cofactor, besides an ancillary antenna chromophore, and a [4Fe-4S] cluster with yet unknown function. For the prokaryotic 6-4 photolyase of Caulobacter crescentus, we investigated structural changes associated with its different redox states by damage-free crystallography using X-ray free-electron lasers. EPR and optical spectroscopy confirmed redox-dependent structural transitions, including the formation of an oxidized [4Fe-4S]3+ cluster with the dynamic cleavage of a single iron-sulfur bond. Photoreduction to the catalytic FADH- state alters the flavin binding site at the proximal aromatic pair Y390/F394 that is part of the electron transport pathway. Upon oxidation, the observable structural transitions of the protein matrix around the [4Fe-4S] cluster may affect DNA binding and are consistent with the much-debated role of the iron-sulfur cluster in DNA-binding proteins for quenching electron holes.
Publisher
American Chemical Society (ACS)
Type
journal article