3W1H

Crystal structure of the selenocysteine synthase SelA from Aquifex aeolicus

3W1H の概要

• エントリーDOI: 10.2210/pdb3w1h/pdb
• 関連するPDBエントリー: 3W1I 3W1J 3W1K
• 分子名称: L-seryl-tRNA(Sec) selenium transferase (1 entity in total)
• 機能のキーワード: homodecamer, pentamer of dimers, fold-type i pyridoxal 5'-phosphate (plp) dependent enzyme, l-seryl-trna(sec) selenium transferase, selenocysteine synthesis, selenium metabolism, transferase
• 由来する生物種: Aquifex aeolicus
• 細胞内の位置: Cytoplasm (By similarity): O67140
• タンパク質・核酸の鎖数: 5
• 化学式量合計: 254625.80

構造登録者

Itoh, Y.,Sekine, S.,Yokoyama, S. (登録日: 2012-11-15, 公開日: 2013-06-05, 最終更新日: 2023-12-06)

主引用文献

Itoh, Y.,Brocker, M.J.,Sekine, S.,Hammond, G.,Suetsugu, S.,Soll, D.,Yokoyama, S.
Decameric SelA-tRNA(Sec) ring structure reveals mechanism of bacterial selenocysteine formation
Science, 340:75-78, 2013

PubMed Abstract: The 21st amino acid, selenocysteine (Sec), is synthesized on its cognate transfer RNA (tRNA(Sec)). In bacteria, SelA synthesizes Sec from Ser-tRNA(Sec), whereas in archaea and eukaryotes SepSecS forms Sec from phosphoserine (Sep) acylated to tRNA(Sec). We determined the crystal structures of Aquifex aeolicus SelA complexes, which revealed a ring-shaped homodecamer that binds 10 tRNA(Sec) molecules, each interacting with four SelA subunits. The SelA N-terminal domain binds the tRNA(Sec)-specific D-arm structure, thereby discriminating Ser-tRNA(Sec) from Ser-tRNA(Ser). A large cleft is created between two subunits and accommodates the 3'-terminal region of Ser-tRNA(Sec). The SelA structures together with in vivo and in vitro enzyme assays show decamerization to be essential for SelA function. SelA catalyzes pyridoxal 5'-phosphate-dependent Sec formation involving Arg residues nonhomologous to those in SepSecS. Different protein architecture and substrate coordination of the bacterial enzyme provide structural evidence for independent evolution of the two Sec synthesis systems present in nature.

PubMed: 23559248
DOI: 10.1126/science.1229521

実験手法

X-RAY DIFFRACTION (3.893 Å)