scholarly journals Hook length of the bacterial flagellum is optimized for maximal stability of the flagellar bundle

PLoS Biology ◽  
2018 ◽  
Vol 16 (9) ◽  
pp. e2006989 ◽  
Author(s):  
Imke Spöring ◽  
Vincent A. Martinez ◽  
Christian Hotz ◽  
Jana Schwarz-Linek ◽  
Keara L. Grady ◽  
...  
Keyword(s):  
Hook Length ◽  
Bacterial Flagellum ◽  
Maximal Stability

scholarly journals Hook-length of the bacterial flagellum is optimized for maximal stability of the flagellar bundle

2018 ◽  
Author(s):  
Imke Spöring ◽  
Vincent A. Martinez ◽  
Christian Hotz ◽  
Jana Schwarz-Linek ◽  
Keara L. Grady ◽  
...  
Keyword(s):  
Basal Body ◽  
Swimming Speed ◽  
Self Assembly ◽  
Nanometer Scale ◽  
Hook Length ◽  
Optimal Length ◽  
Directed Movement ◽  
Bacterial Flagellum ◽  
Evolutionary Forces ◽  
Molecular Ruler

AbstractMost bacteria swim in liquid environments by rotating one or several flagella. The long external filament of the flagellum is connected to a membrane-embedded basal-body by a flexible universal joint, the hook, which allows the transmission of motor torque to the filament. The length of the hook is controlled on a nanometer-scale by a sophisticated molecular ruler mechanism. However, why its length is stringently controlled has remained elusive. We engineered and studied a diverse set of hook-length variants ofSalmonella enterica. Measurements of plate-assay motility, single-cell swimming speed and directional persistence in quasi 2D and population-averaged swimming speed and body angular velocity in 3D revealed that the motility performance is optimal around the wild type hook-length. We conclude that too short hooks may be too stiff to function as a junction and too long hooks may buckle and create instability in the flagellar bundle. Accordingly, peritrichously flagellated bacteria move most efficiently as the distance travelled per body rotation is maximal and body wobbling is minimized. Thus, our results suggest that the molecular ruler mechanism evolved to control flagellar hook growth to the optimal length consistent with efficient bundle formation. The hook-length control mechanism is therefore a prime example of how bacteria evolved elegant, but robust mechanisms to maximize their fitness under specific environmental constraints.Author summaryMany bacteria use flagella for directed movement in liquid environments. The flexible hook connects the membrane-embedded basal-body of the flagellum to the long, external filament. Flagellar function relies on self-assembly processes that define or self-limit the lengths of major parts. The length of the hook is precisely controlled on a nanometer-scale by a molecular ruler mechanism. However, the physiological benefit of tight hook-length control remains unclear. Here, we show that the molecular ruler mechanism evolved to control the optimal length of the flagellar hook, which is consistent with efficient motility performance. These results highlight the evolutionary forces that enable flagellated bacteria to optimize their fitness in diverse environments and might have important implications for the design of swimming micro-robots.

scholarly journals Controlling minimal and maximal hook-length of the bacterial flagellum

2020 ◽  
Author(s):  
Alina Guse ◽  
Manfred Rohde ◽  
Marc Erhardt
Keyword(s):  
Protein Production ◽  
Control Mechanism ◽  
Underlying Mechanism ◽  
Minimal Length ◽  
Deletion Mutants ◽  
Hook Length ◽  
Bacterial Flagellum ◽  
Terminal Domain ◽  
Molecular Ruler ◽  
Measuring Tape

AbstractHook-length control is a central checkpoint during assembly of the bacterial flagellum. During hook growth, a 405 amino acids (aa) protein, FliK, is intermittently secreted and thought to function as a molecular measuring tape that, in Salmonella, controls hook-length to 55 nm ± 6 nm. The underlying mechanism involves interactions of both the α-helical, N-terminal domain of FliK (FliKN) with the hook and hook cap, and of its C-terminal domain with a component of the export apparatus. However, various deletion mutants of FliKN display uncontrolled hook-length, which is not consistent with a ruler mechanism. Here, we carried out an extensive deletion analysis of FliKN to investigate its contribution in the hook-length control mechanism. We identified FliKN mutants deleted for up to 80 aa that retained wildtype motility. However, the short FliK variants did not produce shorter hook-lengths as expected from a physical ruler. Rather, the minimal length of the hook depends on the level of hook protein production and secretion. Our results thus support a model in which FliK functions as a hook growth terminator protein that limits the maximal length of the hook, and not as a molecular ruler that physically measures hook-length.

The three-dimensional structure of frozen-hydrated left- and right-handed forms of bacterial flagellar filaments from an identical serotype

1986 ◽  
Vol 44 ◽  
pp. 298-299
Author(s):  
S. Trachtenberg ◽  
D. J. DeRosier
Keyword(s):  
Ionic Strength ◽  
Basal Body ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Protein Species ◽  
Liquid Environment ◽  
Bacterial Flagellum ◽  
Left And Right ◽  
Rotary Motor ◽  
Helical Parameters

The bacterial cell is propelled through the liquid environment by means of one or more rotating flagella. The bacterial flagellum is composed of a basal body (rotary motor), hook (universal coupler), and filament (propellor). The filament is a rigid helical assembly of only one protein species — flagellin. The filament can adopt different morphologies and change, reversibly, its helical parameters (pitch and hand) as a function of mechanical stress and chemical changes (pH, ionic strength) in the environment.

scholarly journals The role of the FliK molecular ruler in hook-length control inSalmonella enterica

2010 ◽  
Vol 75 (5) ◽  
pp. 1272-1284 ◽  
Author(s):  
Marc Erhardt ◽  
Takanori Hirano ◽  
Yichu Su ◽  
Koushik Paul ◽  
Daniel H. Wee ◽  
...  
Keyword(s):  
Hook Length ◽  
Molecular Ruler

scholarly journals On the growth and zeros of polynomials attached to arithmetic functions

2021 ◽  
Author(s):  
Bernhard Heim ◽  
Markus Neuhauser
Keyword(s):  
Lie Algebras ◽  
Chebyshev Polynomials ◽  
Fourier Coefficients ◽  
Arithmetic Functions ◽  
Zeros Of Polynomials ◽  
Simple Complex ◽  
Hook Length ◽  
Moderate Growth ◽  
Growth Properties ◽  
Sum Of Divisors

AbstractIn this paper we investigate growth properties and the zero distribution of polynomials attached to arithmetic functions g and h, where g is normalized, of moderate growth, and $$0<h(n) \le h(n+1)$$ 0 < h ( n ) ≤ h ( n + 1 ) . We put $$P_0^{g,h}(x)=1$$ P 0 g , h ( x ) = 1 and $$\begin{aligned} P_n^{g,h}(x) := \frac{x}{h(n)} \sum _{k=1}^{n} g(k) \, P_{n-k}^{g,h}(x). \end{aligned}$$ P n g , h ( x ) : = x h ( n ) ∑ k = 1 n g ( k ) P n - k g , h ( x ) . As an application we obtain the best known result on the domain of the non-vanishing of the Fourier coefficients of powers of the Dedekind $$\eta $$ η -function. Here, g is the sum of divisors and h the identity function. Kostant’s result on the representation of simple complex Lie algebras and Han’s results on the Nekrasov–Okounkov hook length formula are extended. The polynomials are related to reciprocals of Eisenstein series, Klein’s j-invariant, and Chebyshev polynomials of the second kind.

FliK, the protein responsible for flagellar hook length control in Salmonella, is exported during hook assembly

1999 ◽  
Vol 34 (2) ◽  
pp. 295-304 ◽  
Author(s):  
Tohru Minamino ◽  
Bertha Gonzalez-Pedrajo ◽  
Kenta Yamaguchi ◽  
Shin-Ichi Aizawa ◽  
Robert M. Macnab
Keyword(s):  
Hook Length

scholarly journals Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure

2021 ◽  
Vol 22 (14) ◽  
pp. 7521
Author(s):  
Marko Nedeljković ◽  
Diego Emiliano Sastre ◽  
Eric John Sundberg
Keyword(s):  
Immune Responses ◽  
Basal Body ◽  
Vaccine Development ◽  
Bacterial Species ◽  
High Variability ◽  
Bacterial Survival ◽  
Bacterial Flagellum ◽  
Capping Proteins ◽  
Flagellar Filament ◽  
Flagellar Assembly

The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.

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