ジャーナル: Nat Commun / 年: 2024 タイトル: Structural basis and synergism of ATP and Na activation in bacterial K uptake system KtrAB. 著者: Wesley Tien Chiang / Yao-Kai Chang / Wei-Han Hui / Shu-Wei Chang / Chen-Yi Liao / Yi-Chuan Chang / Chun-Jung Chen / Wei-Chen Wang / Chien-Chen Lai / Chun-Hsiung Wang / Siou-Ying Luo / Ya-Ping ...著者: Wesley Tien Chiang / Yao-Kai Chang / Wei-Han Hui / Shu-Wei Chang / Chen-Yi Liao / Yi-Chuan Chang / Chun-Jung Chen / Wei-Chen Wang / Chien-Chen Lai / Chun-Hsiung Wang / Siou-Ying Luo / Ya-Ping Huang / Shan-Ho Chou / Tzyy-Leng Horng / Ming-Hon Hou / Stephen P Muench / Ren-Shiang Chen / Ming-Daw Tsai / Nien-Jen Hu / 要旨: 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 ...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.
名称: Bacillus subtilis KtrAB potassium transporter / タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all 詳細: KtrAB complex(chain A-L). KtrAB complex in solution was composed of one KtrA octamer (chain A-H) and two KtrB dimer (chain I-J and chain K-L). The molecule weight of KtrAB complex (chain A-L) is 0.393 MDa
想定した対称性 - 点群: C1 (非対称) / 解像度のタイプ: BY AUTHOR / 解像度: 2.86 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: cryoSPARC (ver. 3.2) 詳細: For KtrB dimer, the symmetry was expended from C2 to C1 and one KtrB dimer was masked when performed the refinement. 使用した粒子像数: 589688