Structures and pH-sensing mechanism of the proton-activated chloride channel.
Structures and pH-sensing mechanism of the proton-activated chloride channel.
复制标题
DOI：
10.1038/s41586-020-2875-7
复制
发表时间：
2020-12
期刊：
影响因子：
64.8
通讯作者：
Lü W
中科院分区：
文献类型：
--
作者：
Ruan Z;Osei-Owusu J;Du J;Qiu Z;Lü W
质子激活氯离子通道（PAC）的活性是广泛的，并参与酸诱导的细胞死亡和组织损伤。它的分子身份最近被确定为一个新的和进化上保守的蛋白质家族。我们提出了两个冷冻EM结构的人PAC在高pH值的休息封闭状态和低pH值的质子结合的非导电状态。PAC是三聚体;每个亚基由两个螺旋形成的跨膜结构域（TMD）、TM 1 -2和细胞外结构域（ECD）组成。我们观察到显着的构象变化，在ECD-TMD界面和TMD时，pH值从8下降到4。ECD-TMD界面的重排的特征在于组氨酸-98的移动，组氨酸-98在酸化时从静止位置解偶联并插入到约5 μ m远的酸性口袋中。在TMD内，TM 1经历旋转运动，将其相互作用伙伴从同源切换到相邻的TM 2。PAC的阴离子选择性由TM 2上带正电荷的赖氨酸-319决定。用谷氨酸盐替换赖氨酸-319将PAC转化为阳离子选择性通道。我们的数据提供了第一次瞥见PAC的分子组装，并为理解质子依赖性活化机制奠定了基础。
The activity of the proton-activated chloride channel (PAC) is widespread and is involved in acid-induced cell death and tissue injury. Its molecular identity has recently been identified as a novel and evolutionarily conserved protein family. We present two cryo-EM structures of human PAC in a high-pH resting closed state and a low-pH proton-bound non-conducting state. PAC is a trimer; each subunit consists of a transmembrane domain (TMD) formed by two helices, TM1–2, and an extracellular domain (ECD). We observed striking conformational changes in the ECD–TMD interface and the TMD when the pH drops from 8 to 4. The rearrangement of the ECD–TMD interface is characterized by the movement of histidine-98, which is, upon acidification, decoupled from the resting position and inserted into an acidic pocket that is about 5-Å away. Within the TMD, TM1 undergoes a rotational movement, switching its interaction partner from the cognate to the adjacent TM2. The anion selectivity of PAC is determined by the positively charged lysine-319 on TM2. Replacement of lysine-319 by a glutamate converts PAC to a cation-selective channel. Our data provide the first glimpse of the molecular assembly of PAC, and a basis for understanding the mechanism of proton-dependent activation.
登录
查看更多内容
DOI：
10.1107/s2059798318009324
发表时间：
2018-09-01
期刊：
Acta crystallographica. Section D, Structural biology
影响因子：
--
作者：
Afonine PV;Klaholz BP;Moriarty NW;Poon BK;Sobolev OV;Terwilliger TC;Adams PD;Urzhumtsev A
通讯作者：
Urzhumtsev A
影响因子：
64.8
作者：
Gonzales, Eric B.;Kawate, Toshimitsu;Gouaux, Eric
通讯作者：
Gouaux, Eric
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
48
作者：
Punjani, Ali;Rubinstein, John L.;Brubaker, Marcus A.
通讯作者：
Brubaker, Marcus A.
影响因子：
5.5
作者：
Hess, Berk
通讯作者：
Hess, Berk