2MN6

Solution structure of dimeric TatA of twin-arginine translocation system from E. coli

2MN6 の概要

• エントリーDOI: 10.2210/pdb2mn6/pdb
• 関連するPDBエントリー: 2MN7
• NMR情報: BMRB: 19714
• 分子名称: Sec-independent protein translocase protein TatA (1 entity in total)
• 機能のキーワード: transport protein
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cell inner membrane ; Single- pass membrane protein ; Cytoplasmic side : P69428
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 22081.02

構造登録者

Zhang, Y.,Hu, Y.,Jin, C. (登録日: 2014-03-31, 公開日: 2015-04-15, 最終更新日: 2024-05-01)

主引用文献

Zhang, Y.,Hu, Y.,Li, H.,Jin, C.
Structural basis for TatA oligomerization: an NMR study of Escherichia coli TatA dimeric structure
Plos One, 9:e103157-e103157, 2014

PubMed Abstract: Many proteins are transported across lipid membranes by protein translocation systems in living cells. The twin-arginine transport (Tat) system identified in bacteria and plant chloroplasts is a unique system that transports proteins across membranes in their fully-folded states. Up to date, the detailed molecular mechanism of this process remains largely unclear. The Escherichia coli Tat system consists of three essential transmembrane proteins: TatA, TatB and TatC. Among them, TatB and TatC form a tight complex and function in substrate recognition. The major component TatA contains a single transmembrane helix followed by an amphipathic helix, and is suggested to form the translocation pore via self-oligomerization. Since the TatA oligomer has to accommodate substrate proteins of various sizes and shapes, the process of its assembly stands essential for understanding the translocation mechanism. A structure model of TatA oligomer was recently proposed based on NMR and EPR observations, revealing contacts between the transmembrane helices from adjacent subunits. Herein we report the construction and stabilization of a dimeric TatA, as well as the structure determination by solution NMR spectroscopy. In addition to more extensive inter-subunit contacts between the transmembrane helices, we were also able to observe interactions between neighbouring amphipathic helices. The side-by-side packing of the amphipathic helices extends the solvent-exposed hydrophilic surface of the protein, which might be favourable for interactions with substrate proteins. The dimeric TatA structure offers more detailed information of TatA oligomeric interface and provides new insights on Tat translocation mechanism.

PubMed: 25090434
DOI: 10.1371/journal.pone.0103157

実験手法

SOLUTION NMR