8XMH

Potassium transporter KtrAB from Bacillus subtilis in ATP-bound state with addition of EDTA and EGTA, vertical C2 symmetry axis

8XMH の概要

• エントリーDOI: 10.2210/pdb8xmh/pdb
• EMDBエントリー: 38477
• 分子名称: Ktr system potassium uptake protein A, Ktr system potassium uptake protein B, ADENOSINE-5'-TRIPHOSPHATE, ... (5 entities in total)
• 機能のキーワード: ktrab, rck, potassium, transporter, transport protein
• 由来する生物種: Bacillus subtilis; 詳細
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 397526.04

構造登録者

Chang, Y.K.,Chiang, W.T.,Hu, N.J.,Tsai, M.D. (登録日: 2023-12-27, 公開日: 2024-04-03, 最終更新日: 2024-05-22)

主引用文献

Chiang, W.T.,Chang, Y.K.,Hui, W.H.,Chang, S.W.,Liao, C.Y.,Chang, Y.C.,Chen, C.J.,Wang, W.C.,Lai, C.C.,Wang, C.H.,Luo, S.Y.,Huang, Y.P.,Chou, S.H.,Horng, T.L.,Hou, M.H.,Muench, S.P.,Chen, R.S.,Tsai, M.D.,Hu, N.J.
Structural basis and synergism of ATP and Na + activation in bacterial K + uptake system KtrAB.
Nat Commun, 15:3850-3850, 2024

PubMed Abstract: The K uptake system KtrAB is essential for bacterial survival in low K environments. The activity of KtrAB is regulated by nucleotides and Na. Previous studies proposed a putative gating mechanism of KtrB regulated by KtrA upon binding to ATP or ADP. However, how Na activates KtrAB and the Na binding site remain unknown. Here we present the cryo-EM structures of ATP- and ADP-bound KtrAB from Bacillus subtilis (BsKtrAB) both solved at 2.8 Å. A cryo-EM density at the intra-dimer interface of ATP-KtrA was identified as Na, as supported by X-ray crystallography and ICP-MS. Thermostability assays and functional studies demonstrated that Na binding stabilizes the ATP-bound BsKtrAB complex and enhances its K flux activity. Comparing ATP- and ADP-BsKtrAB structures suggests that BsKtrB Arg417 and Phe91 serve as a channel gate. The synergism of ATP and Na in activating BsKtrAB is likely applicable to Na-activated K channels in central nervous system.

PubMed: 38719864
DOI: 10.1038/s41467-024-48057-y

実験手法

ELECTRON MICROSCOPY (2.85 Å)