Structural differences in the bacterial flagellar motor among bacterial species

Abstract

The bacterial flagellum is a supramolecular motility machine consisting of the basal body as a rotary motor, the hook as a universal joint, and the filament as a helical propeller. Intact structures of the bacterial flagella have been observed for different bacterial species by electron cryotomography and subtomogram averaging. The core structures of the basal body consisting of the C ring, the MS ring, the rod and the protein export apparatus, and their organization are well conserved, but novel and divergent structures have also been visualized to surround the conserved structure of the basal body. This suggests that the flagellar motors have adapted to function in various environments where bacteria live and survive. In this review, we will summarize our current findings on the divergent structures of the bacterial flagellar motor.

In situ imaging of the bacterial flagellar motor disassembly and assembly processes

“…Recently, the advent of electron cryo‐tomography (ECT) (Gan & Jensen, ; Oikonomou & Jensen, ) allowed our group and others to reveal the in situ structures of various bacterial flagellar motors within intact cells at macromolecular (~4 nm) resolution. These studies showed the diversity of flagellar motors in different species adapted to unique external environments (Chen et al , ; Zhao et al , ; Minamino & Imada, ; Terashima et al , ; Zhu et al , ; Kaplan et al , ). For instance, some species elaborate their P‐ and L‐rings with additional periplasmic components, including the T‐ring (MotX and MotY) and H‐ring (FlgO, FlgP, and FlgT) (Terashima et al , , ; Beeby et al , ; Chaban et al , ).…”

Autonomous control mechanism of stator assembly in the bacterial flagellar motor in response to changes in the environment

“…The flagellar motor can also respond to changes in the environment by itself, inducing developmental changes such as cell differentiation and biofilm formation in planktonic cells for their survival. Therefore, it is believed that the flagellar motor has adopted and evolved to function in various environments where bacteria live and survive (Minamino and Imada, 2015;Terashima et al, 2017).…”

Twitch or swim: towards the understanding of prokaryotic motion based on the type IV pilus blueprint

“…The most well-studied form of prokaryotic motility stems from the bacterial flagellum (Imada, 2017;Terashima et al, 2017;Khan and Scholey, 2018), which is used primarily for swimming in aqueous environments. It is a massive structure, powered by an ion gradient, that acts as a rotary propeller to drive directional movement (Imada, 2017;Terashima et al, 2017;Khan and Scholey, 2018). In terms of mechanics, this type of motility would not be particularly well suited for movement along surfaces, which a large proportion of bacteria colonise.…”