Download MendeleyStructural Evidence for a [4Fe-5S] Intermediate in the Non-Redox Desulfuration of Thiouracil.
Zhou, J., Pecqueur, L., Aucynaite, A., Fuchs, J., Rutkiene, R., Vaitekunas, J., Meskys, R., Boll, M., Fontecave, M., Urbonavicius, J., Golinelli-Pimpaneau, B.(2021) Angew Chem Int Ed Engl 60: 424-431
- PubMed: 32929873
- DOI: https://doi.org/10.1002/anie.202011211
- Primary Citation of Related Structures:
6Z92, 6Z93, 6Z94, 6Z96, 6ZW9 - PubMed Abstract:
We recently discovered a [Fe-S]-containing protein with in vivo thiouracil desulfidase activity, dubbed TudS. The crystal structure of TudS refined at 1.5 Å resolution is reported; it harbors a [4Fe-4S] cluster bound by three cysteines only. Incubation of TudS crystals with 4-thiouracil trapped the cluster with a hydrosulfide ligand bound to the fourth non-protein-bonded iron, as established by the sulfur anomalous signal. This indicates that a [4Fe-5S] state of the cluster is a catalytic intermediate in the desulfuration reaction. Structural data and site-directed mutagenesis indicate that a water molecule is located next to the hydrosulfide ligand and to two catalytically important residues, Ser101 and Glu45. This information, together with modeling studies allow us to propose a mechanism for the unprecedented non-redox enzymatic desulfuration of thiouracil, in which a [4Fe-4S] cluster binds and activates the sulfur atom of the substrate.
Organizational Affiliation:
Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, Collège de France, Sorbonne Université, Paris CEDEX 05, France.
