Structural Conservation and Adaptation of the Bacterial Flagella Motor

Carroll, Brittany L.; Li, Jun

doi:10.3390/biom10111492

Cited by 35 publications

(37 citation statements)

References 230 publications

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“…[ 76 ] managed to observe in detail the flagellar rotation of the archaeon Halobacterium salinarum and estimated its motor torque to be as low as 50 pN nm. However, different species of bacteria can have very different motor structures [ 83 ], which leads to a wide range of possible values for the propulsive torque [ 84 ].…”

Section: Bacteria and Archaeamentioning

confidence: 99%

The bank of swimming organisms at the micron scale (BOSO-Micro)

2021

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Unicellular microscopic organisms living in aqueous environments outnumber all other creatures on Earth. A large proportion of them are able to self-propel in fluids with a vast diversity of swimming gaits and motility patterns. In this paper we present a biophysical survey of the available experimental data produced to date on the characteristics of motile behaviour in unicellular microswimmers. We assemble from the available literature empirical data on the motility of four broad categories of organisms: bacteria (and archaea), flagellated eukaryotes, spermatozoa and ciliates. Whenever possible, we gather the following biological, morphological, kinematic and dynamical parameters: species, geometry and size of the organisms, swimming speeds, actuation frequencies, actuation amplitudes, number of flagella and properties of the surrounding fluid. We then organise the data using the established fluid mechanics principles for propulsion at low Reynolds number. Specifically, we use theoretical biophysical models for the locomotion of cells within the same taxonomic groups of organisms as a means of rationalising the raw material we have assembled, while demonstrating the variability for organisms of different species within the same group. The material gathered in our work is an attempt to summarise the available experimental data in the field, providing a convenient and practical reference point for future studies.

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Section: Bacteria and Archaeamentioning

confidence: 99%

The bank of swimming organisms at the micron scale (BOSO-Micro)

2021

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“…Among them, the most intricate part is the basal body, containing the components responsible for assembly of the flagellum [the flagellar-specific type-III secretion system (T3SS) [8]], torque generation (the stator units [9]), and rotational switching (binding of the response regulator CheY-P to the cytoplasmic C-ring [10,11]). Cryo-ET studies of the motor from different bacterial species show the variation of its structure, while the core components are conserved [7,12,13]. For example, in the Gram-negative bacteria Salmonella and E. coli, the flagellar motor contains four ring-like structures based on their distributions relative to the cell surface layers [lipopolysaccharide (L-)ring, peptidoglycan (P-)ring, inner membrane/ supramembrane (MS-)ring, and cytoplasmic (C-)ring] surrounding a central rigid rod [14][15][16][17].…”

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confidence: 99%

Structural basis of torque generation in the bi-directional bacterial flagellar motor

Santiveri

Wadhwa

et al. 2022

Trends in Biochemical Sciences

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The flagellar stator unit is an oligomeric complex of two membrane proteins (MotA 5 B 2 ) that powers bi-directional rotation of the bacterial flagellum. Harnessing the ion motive force across the cytoplasmic membrane, the stator unit operates as a miniature rotary motor itself to provide torque for rotation of the flagellum. Recent cryo-electron microscopic (cryo-EM) structures of the stator unit provided novel insights into its assembly, function, and subunit stoichiometry, revealing the ion flux pathway and the torque generation mechanism. Furthermore, in situ cryoelectron tomography (cryo-ET) studies revealed unprecedented details of the interactions between stator unit and rotor. In this review, we summarize recent advances in our understanding of the structure and function of the flagellar stator unit, torque generation, and directional switching of the motor. The bacterial flagellum and its rotary motorMany bacteria, including Escherichia coli, Salmonella, and Bacillus spp., use flagella (see Glossary) to move through liquid environments and across surfaces. The flagellum is a supramolecular nanomachine that protrudes from the cell envelope and measures~5-20 μm in length. It is able to rotate in both clockwise (CW) and counterclockwise (CCW) directions to propel the bacterial cell body in different living environments [1,2]. Rotational switching between these two modes is regulated by chemotactic signaling, which is a rapid process that responds to environmental stimuli and biases movement of the cell toward attractants and away from repellents. Flagella-mediated chemotaxis further enables pathogenic bacteria to move toward cells to establish in vivo niches. [3,4]. Thus, flagella have fundamental roles in bacterial locomotion and virulence [5].The flagellum comprises more than 25 kinds of building blocks, which assemble in a highly ordered manner. The flagellar structure can be divided into three morphologically distinguishable parts: a cell envelope-spanning motor (basal body), a universal joint (hook), and a long, thin helical filament [6,7] (Figure 1). Among them, the most intricate part is the basal body, containing the components responsible for assembly of the flagellum [the flagellar-specific type-III secretion system (T3SS) [8]], torque generation (the stator units [9]), and rotational switching (binding of the response regulator CheY-P to the cytoplasmic C-ring [10,11]). Cryo-ET studies of the motor from different bacterial species show the variation of its structure, while the core components are conserved [7,12,13]. For example, in the Gram-negative bacteria Salmonella and E. coli, the flagellar motor contains four ring-like structures based on their distributions relative to the cell surface layers [lipopolysaccharide (L-)ring, peptidoglycan (P-)ring, inner membrane/ supramembrane (MS-)ring, and cytoplasmic (C-)ring] surrounding a central rigid rod [14][15][16][17]. Additional ring-like structures, H-and T-rings, located in the periplasmic space, have also been observed in Vibrio spp [18]. It i...

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“…All review articles provide both expert and non-expert readers with advances in understanding the structures and functions of the bacterial flagellum. They highlight the most recent observations and illustrate perspectives for future research [4][5][6][7][8][9][10][11][12][13].…”

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confidence: 85%

“…The scope of this Special Issue is to cover recent advances in our understanding of the structures and functions of the bacterial flagellar motor derived from different bacterial species. This Special Issue includes ten review articles [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ] and eleven original research papers [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ] from well-known experts in the field.…”

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confidence: 99%