Structure of MotA, a flagellar stator protein, from hyperthermophile
Structure of MotA, a flagellar stator protein, from hyperthermophile
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MotA（一种来自超嗜热生物的鞭毛定子蛋白）的结构
DOI：
10.1016/j.bbrc.2022.09.072
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发表时间：
2023
影响因子：
3.1
通讯作者：
Takayuki Kato and Katsumi Imada
中科院分区：
文献类型：
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作者：
Tatsuro Nishikino;Norihiro Takekawa;Duy Phuoc Tran;Jun-ichi Kishikawa;Mika Hirose;Sakura Onoe;Seiji Kojima;Michio Homma;Akio Kitao;Takayuki Kato and Katsumi Imada
许多可移动的细菌利用鞭毛游向有利的环境，鞭毛由嵌入内膜的马达旋转。电机由转子和定子组成，电机的力矩是通过定子上的离子流引起转子和定子之间相互作用的变化而产生的。一个定子单元由两种膜蛋白组成，称为A和B。最近对中温生物定子的冷冻-EM研究表明，定子由五个A和两个B亚基组成，而低分辨EM分析表明，纯化的超高温Mota形成四聚体。为了阐明超嗜热定子的组装形式和提高热稳定性的因素，我们测定了超嗜热菌Aquifex aeolicus(AA-MoTA)MoTA的低温EM结构，分辨率为3.42°。AA-MoTA形成具有伪C5对称性的五聚体。AA-MotA5MotB2定子络合物的模拟模型类似于中温定子络合物的结构，表明AA-MoTA可以组装成与没有MOTB的定子络合物等价的五聚体。MOTA五聚体疏水残基的分布表明，亚基边界和跨膜区的极端疏水性质是稳定高温AA-MOTA的关键因素。
Many motile bacteria swim and swarm toward favorable environments using the flagellum, which is rotated by a motor embedded in the inner membrane. The motor is composed of the rotor and the stator, and the motor torque is generated by the change of the interaction between the rotor and the stator induced by the ion flow through the stator. A stator unit consists of two types of membrane proteins termed A and B. Recent cryo-EM studies on the stators from mesophiles revealed that the stator consists of five A and two B subunits, whereas the low-resolution EM analysis showed that purified hyperthermophilic MotA forms a tetramer. To clarify the assembly formation and factors enhancing thermostability of the hyperthermophilic stator, we determined the cryo-EM structure of MotA from Aquifex aeolicus (Aa-MotA), a hyperthermophilic bacterium, at 3.42 Å resolution. Aa-MotA forms a pentamer with pseudo C5 symmetry. A simulated model of the Aa-MotA5MotB2stator complex resembles the structures of mesophilic stator complexes, suggesting that Aa-MotA can assemble into a pentamer equivalent to the stator complex without MotB. The distribution of hydrophobic residues of MotA pentamers suggests that the extremely hydrophobic nature in the subunit boundary and the transmembrane region is a key factor to stabilize hyperthermophilic Aa-MotA.