5gha

Sulfur Transferase TtuA in complex with Sulfur Carrier TtuB

spinqualitylabelsall models 5gha, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5gha is a 8 chain structure with sequence from Thet2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EDO, SO4, ZN Related: 5b4e Gene: TT_C0106 (THET2), TT_C0105 (THET2) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Two-thiouridine (s2U) at position 54 of transfer RNA (tRNA) is a posttranscriptional modification that enables thermophilic bacteria to survive in high-temperature environments. s2U is produced by the combined action of two proteins, 2-thiouridine synthetase TtuA and 2-thiouridine synthesis sulfur carrier protein TtuB, which act as a sulfur (S) transfer enzyme and a ubiquitin-like S donor, respectively. Despite the accumulation of biochemical data in vivo, the enzymatic activity by TtuA/TtuB has rarely been observed in vitro, which has hindered examination of the molecular mechanism of S transfer. Here we demonstrate by spectroscopic, biochemical, and crystal structure analyses that TtuA requires oxygen-labile [4Fe-4S]-type iron (Fe)-S clusters for its enzymatic activity, which explains the previously observed inactivation of this enzyme in vitro. The [4Fe-4S] cluster was coordinated by three highly conserved cysteine residues, and one of the Fe atoms was exposed to the active site. Furthermore, the crystal structure of the TtuA-TtuB complex was determined at a resolution of 2.5 A, which clearly shows the S transfer of TtuB to tRNA using its C-terminal thiocarboxylate group. The active site of TtuA is connected to the outside by two channels, one occupied by TtuB and the other used for tRNA binding. Based on these observations, we propose a molecular mechanism of S transfer by TtuA using the ubiquitin-like S donor and the [4Fe-4S] cluster. Biochemical and structural characterization of oxygen-sensitive 2-thiouridine synthesis catalyzed by an iron-sulfur protein TtuA.,Chen M, Asai SI, Narai S, Nambu S, Omura N, Sakaguchi Y, Suzuki T, Ikeda-Saito M, Watanabe K, Yao M, Shigi N, Tanaka Y Proc Natl Acad Sci U S A. 2017 Apr 24. pii: 201615585. doi:, 10.1073/pnas.1615585114. PMID:28439027 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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