- EMDB-37377: structure of AtHKT1;1 in KCl at 2.8 Angstroms resolution -
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基本情報
登録情報
データベース: EMDB / ID: EMD-37377
タイトル
structure of AtHKT1;1 in KCl at 2.8 Angstroms resolution
マップデータ
試料
複合体: structure of AtHKT1;1 in KCl at 2.8 Angstroms resolution
タンパク質・ペプチド: Sodium transporter HKT1
リガンド: POTASSIUM ION
キーワード
HKT / ion selectivity / salt tolerance / TRANSPORT PROTEIN
機能・相同性
機能・相同性情報
potassium ion transmembrane transporter activity / response to osmotic stress / sodium ion transport / response to salt stress / potassium ion transport / plasma membrane 類似検索 - 分子機能
Potassium/sodium transporter Trk/HKT / : / Cation transporter / Cation transport protein 類似検索 - ドメイン・相同性
National Natural Science Foundation of China (NSFC)
31870724
中国
引用
ジャーナル: Mol Plant / 年: 2024 タイトル: Structures and ion transport mechanisms of plant high-affinity potassium transporters. 著者: Jiangqin Wang / Yanping Luo / Fan Ye / Zhong Jie Ding / Shao Jian Zheng / Shuai Qiao / Yong Wang / Jiangtao Guo / Wei Yang / Nannan Su / 要旨: Plant high-affinity K transporters (HKTs) mediate Na and K uptake, maintain Na/K homeostasis, and therefore play crucial roles in plant salt tolerance. In this study, we present cryoelectron ...Plant high-affinity K transporters (HKTs) mediate Na and K uptake, maintain Na/K homeostasis, and therefore play crucial roles in plant salt tolerance. In this study, we present cryoelectron microscopy structures of HKTs from two classes, class I HKT1;1 from Arabidopsis thaliana (AtHKT1;1) and class II HKT2;1 from Triticum aestivum (TaHKT2;1), in both Na- and K-bound states at 2.6- to 3.0-Å resolutions. Both AtHKT1;1 and TaHKT2;1 function as homodimers. Each HKT subunit consists of four tandem domain units (D1-D4) with a repeated K-channel-like M-P-M topology. In each subunit, D1-D4 assemble into an ion conduction pore with a pseudo-four-fold symmetry. Although both TaHKT2;1 and AtHKT1;1 have only one putative Na ion bound in the selectivity filter with a similar coordination pattern, the two HKTs display different K binding modes in the filter. TaHKT2;1 has three K ions bound in the selectivity filter, but AtHKT1;1 has only two K ions bound in the filter, which has a narrowed external entrance due to the presence of a Ser residue in the first filter motif. These structures, along with computational, mutational, and electrophysiological analyses, enable us to pinpoint key residues that are critical for the ion selectivity of HKTs. The findings provide new insights into the ion selectivity and ion transport mechanisms of plant HKTs and improve our understanding about how HKTs mediate plant salt tolerance and enhance crop growth.