5MKQ

TtuA enzyme containing a [4Fe-4S]

Summary for 5MKQ

• Entry DOI: 10.2210/pdb5mkq/pdb
• Descriptor: TtuA PH0300, ZINC ION, IRON/SULFUR CLUSTER, ... (4 entities in total)
• Functional Keywords: ttua, ph0300, apo, 4fe-4s, fe-edge, anomal, iron-sulfur cluster, trna thiolation, trna modification, rna, oxidoreductase
• Biological source: Pyrococcus horikoshii (strain ATCC 700860 / DSM 12428 / JCM 9974 / NBRC 100139 / OT-3)
• Total number of polymer chains: 2
• Total formula weight: 72810.67

Authors

Arragain, S.,Bimai, O.,Legrand, P.,Golinelli-Pimpaneau, B. (deposition date: 2016-12-05, release date: 2017-06-14, Last modification date: 2024-01-17)

Primary citation

Arragain, S.,Bimai, O.,Legrand, P.,Caillat, S.,Ravanat, J.L.,Touati, N.,Binet, L.,Atta, M.,Fontecave, M.,Golinelli-Pimpaneau, B.
Nonredox thiolation in tRNA occurring via sulfur activation by a [4Fe-4S] cluster.
Proc. Natl. Acad. Sci. U.S.A., 114:7355-7360, 2017

PubMed Abstract: Sulfur is present in several nucleosides within tRNAs. In particular, thiolation of the universally conserved methyl-uridine at position 54 stabilizes tRNAs from thermophilic bacteria and hyperthermophilic archaea and is required for growth at high temperature. The simple nonredox substitution of the C2-uridine carbonyl oxygen by sulfur is catalyzed by tRNA thiouridine synthetases called TtuA. Spectroscopic, enzymatic, and structural studies indicate that TtuA carries a catalytically essential [4Fe-4S] cluster and requires ATP for activity. A series of crystal structures shows that () the cluster is ligated by only three cysteines that are fully conserved, allowing the fourth unique iron to bind a small ligand, such as exogenous sulfide, and () the ATP binding site, localized thanks to a protein-bound AMP molecule, a reaction product, is adjacent to the cluster. A mechanism for tRNA sulfuration is suggested, in which the unique iron of the catalytic cluster serves to bind exogenous sulfide, thus acting as a sulfur carrier.

PubMed: 28655838
DOI: 10.1073/pnas.1700902114

Experimental method

X-RAY DIFFRACTION (2.79 Å)