Morimoto Yusuke V, Minamino Tohru
Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan.
Graduate School of Frontier Biosciences, Osaka University 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
Biomolecules. 2014 Feb 18;4(1):217-34. doi: 10.3390/biom4010217.
The bacterial flagellum is a locomotive organelle that propels the bacterial cell body in liquid environments. The flagellum is a supramolecular complex composed of about 30 different proteins and consists of at least three parts: a rotary motor, a universal joint, and a helical filament. The flagellar motor of Escherichia coli and Salmonella enterica is powered by an inward-directed electrochemical potential difference of protons across the cytoplasmic membrane. The flagellar motor consists of a rotor made of FliF, FliG, FliM and FliN and a dozen stators consisting of MotA and MotB. FliG, FliM and FliN also act as a molecular switch, enabling the motor to spin in both counterclockwise and clockwise directions. Each stator is anchored to the peptidoglycan layer through the C-terminal periplasmic domain of MotB and acts as a proton channel to couple the proton flow through the channel with torque generation. Highly conserved charged residues at the rotor-stator interface are required not only for torque generation but also for stator assembly around the rotor. In this review, we will summarize our current understanding of the structure and function of the proton-driven bacterial flagellar motor.
细菌鞭毛是一种运动细胞器，可在液体环境中推动细菌细胞体。鞭毛是一种由约30种不同蛋白质组成的超分子复合物，至少由三部分组成：旋转马达、万向节和螺旋丝。大肠杆菌和肠炎沙门氏菌的鞭毛马达由质子跨细胞质膜向内的电化学势差提供动力。鞭毛马达由由FliF、FliG、FliM和FliN组成的转子和由MotA和MotB组成的十几个定子组成。FliG、FliM和FliN还充当分子开关，使马达能够逆时针和顺时针方向旋转。每个定子通过MotB的C端周质结构域锚定在肽聚糖层上，并作为质子通道，将通过通道的质子流与扭矩产生耦合。转子-定子界面处高度保守的带电残基不仅是产生扭矩所必需的，也是定子围绕转子组装所必需的。在这篇综述中，我们将总结我们目前对质子驱动的细菌鞭毛马达的结构和功能的理解。
