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
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...
May 8, 2024: Nature Communications