5GHA

Sulfur Transferase TtuA in complex with Sulfur Carrier TtuB

5GHA の概要

• エントリーDOI: 10.2210/pdb5gha/pdb
• 関連するPDBエントリー: 5B4E
• 分子名称: Sulfur Transferase TtuA, Sulfur Carrier TtuB, ZINC ION, ... (6 entities in total)
• 機能のキーワード: sulfur transferase, transferase, transferase-transport protein complex, transferase/transport protein
• 由来する生物種: Thermus thermophilus HB27; 詳細
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 184339.98

構造登録者

Chen, M.,Narai, S.,Tanaka, Y.,Yao, M. (登録日: 2016-06-19, 公開日: 2017-05-03, 最終更新日: 2024-03-20)

主引用文献

Chen, M.,Asai, S.,Narai, S.,Nambu, S.,Omura, N.,Sakaguchi, Y.,Suzuki, T.,Ikeda-Saito, M.,Watanabe, K.,Yao, M.,Shigi, N.,Tanaka, Y.
Biochemical and structural characterization of oxygen-sensitive 2-thiouridine synthesis catalyzed by an iron-sulfur protein TtuA
Proc. Natl. Acad. Sci. U.S.A., 114:4954-4959, 2017

PubMed Abstract: Two-thiouridine (sU) at position 54 of transfer RNA (tRNA) is a posttranscriptional modification that enables thermophilic bacteria to survive in high-temperature environments. sU 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 Å, 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.

PubMed: 28439027
DOI: 10.1073/pnas.1615585114

実験手法

X-RAY DIFFRACTION (2.502 Å)