scholarly journals Bacterial flagella grow through an injection-diffusion mechanism

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Thibaud T Renault ◽  
Anthony O Abraham ◽  
Tobias Bergmiller ◽  
Guillaume Paradis ◽  
Simon Rainville ◽  
...  
Keyword(s):  
Fundamental Problem ◽  
Diffusion Mechanism ◽  
Chain Mechanism ◽  
Bacterial Flagellum ◽  
Bacterial Flagella ◽  
Self Assembling ◽  
Single Protein ◽  
Flagellar Filament ◽  
Dynamic Assembly

The bacterial flagellum is a self-assembling nanomachine. The external flagellar filament, several times longer than a bacterial cell body, is made of a few tens of thousands subunits of a single protein: flagellin. A fundamental problem concerns the molecular mechanism of how the flagellum grows outside the cell, where no discernible energy source is available. Here, we monitored the dynamic assembly of individual flagella using in situ labelling and real-time immunostaining of elongating flagellar filaments. We report that the rate of flagellum growth, initially ∼1,700 amino acids per second, decreases with length and that the previously proposed chain mechanism does not contribute to the filament elongation dynamics. Inhibition of the proton motive force-dependent export apparatus revealed a major contribution of substrate injection in driving filament elongation. The combination of experimental and mathematical evidence demonstrates that a simple, injection-diffusion mechanism controls bacterial flagella growth outside the cell.

scholarly journals Molecular structure of the intact bacterial flagellar basal body

2020 ◽  
Author(s):  
Steven Johnson ◽  
Emily J. Furlong ◽  
Justin C. Deme ◽  
Ashley L. Nord ◽  
Joseph Caesar ◽  
...  
Keyword(s):  
Basal Body ◽  
Drive Shaft ◽  
Inner Membrane ◽  
Bacterial Flagella ◽  
Cryo Electron Microscopy ◽  
Different Types ◽  
Flagellar Filament ◽  
A Cell ◽  
Insight Into

AbstractBacterial flagella self-assemble a strong, multi-component drive shaft that couples rotation in the inner membrane to the microns-long flagellar filament that powers bacterial swimming in viscous fluids. We here present structures of the intact Salmonella flagellar basal body, solved using cryo-electron microscopy to resolutions between 2.2 and 3.7 Å. The structures reveal molecular details of how 173 protein molecules of 13 different types assemble into a complex spanning two membranes and a cell wall. The helical drive shaft at one end is intricately interwoven with the inner membrane rotor component, and at the other end passes through a molecular bearing that is anchored in the outer membrane via interactions with the lipopolysaccharide. The in situ structure of a protein complex capping the drive shaft provides molecular insight into the assembly process of this molecular machine.

scholarly journals Oligomerization of the FliF Domains Suggests a Coordinated Assembly of the Bacterial Flagellum MS Ring

2022 ◽  
Vol 12 ◽  
Author(s):  
Giuseppina Mariano ◽  
Raquel Faba-Rodriguez ◽  
Soi Bui ◽  
Weilong Zhao ◽  
James Ross ◽  
...  
Keyword(s):  
Basal Body ◽  
Computational Analysis ◽  
Cell Envelope ◽  
Bacterial Flagellum ◽  
Self Assembling ◽  
Single Protein ◽  
Serovar Typhimurium ◽  
Ring Structures ◽  
Periplasmic Domain ◽  
The Individual

The bacterial flagellum is a complex, self-assembling macromolecular machine that powers bacterial motility. It plays diverse roles in bacterial virulence, including aiding in colonization and dissemination during infection. The flagellum consists of a filamentous structure protruding from the cell, and of the basal body, a large assembly that spans the cell envelope. The basal body is comprised of over 20 different proteins forming several concentric ring structures, termed the M- S- L- P- and C-rings, respectively. In particular, the MS rings are formed by a single protein FliF, which consists of two trans-membrane helices anchoring it to the inner membrane and surrounding a large periplasmic domain. Assembly of the MS ring, through oligomerization of FliF, is one of the first steps of basal body assembly. Previous computational analysis had shown that the periplasmic region of FliF consists of three structurally similar domains, termed Ring-Building Motif (RBM)1, RBM2, and RBM3. The structure of the MS-ring has been reported recently, and unexpectedly shown that these three domains adopt different symmetries, with RBM3 having a 34-mer stoichiometry, while RBM2 adopts two distinct positions in the complex, including a 23-mer ring. This observation raises some important question on the assembly of the MS ring, and the formation of this symmetry mismatch within a single protein. In this study, we analyze the oligomerization of the individual RBM domains in isolation, in the Salmonella enterica serovar Typhimurium FliF ortholog. We demonstrate that the periplasmic domain of FliF assembles into the MS ring, in the absence of the trans-membrane helices. We also report that the RBM2 and RBM3 domains oligomerize into ring structures, but not RBM1. Intriguingly, we observe that a construct encompassing RBM1 and RBM2 is monomeric, suggesting that RBM1 interacts with RBM2, and inhibits its oligomerization. However, this inhibition is lifted by the addition of RBM3. Collectively, this data suggest a mechanism for the controlled assembly of the MS ring.

scholarly journals Oligomerization of the FliF domains suggests a coordinated assembly of the bacterial flagellum MS ring

2021 ◽  
Author(s):  
Giuseppina Mariano ◽  
Raquel Faba-Rodriguez ◽  
Soi Bui ◽  
Weilong Zhao ◽  
James Ross ◽  
...  
Keyword(s):  
Basal Body ◽  
Computational Analysis ◽  
Cell Envelope ◽  
Concentric Ring ◽  
Bacterial Flagellum ◽  
Self Assembling ◽  
Single Protein ◽  
Ring Structures ◽  
Periplasmic Domain ◽  
The Individual

The bacterial flagellum is a complex, self-assembling macromolecular machine that powers bacterial motility. It plays diverse roles in bacterial virulence, including aiding in colonization and dissemination during infection. The flagellum consists of a filamentous structure protruding from the cell, and the basal body, a large assembly that spans the cell envelope. The basal body is comprised of over 10 different proteins, forming several concentric ring structures, termed the M- S- L- P- and C-rings, respectively. In particular, the MS rings are formed by a single protein FliF, which consists of two trans-membrane helices anchoring it to the inner membrane and surrounding a large periplasmic domain. Assembly of the MS ring, through oligomerization of FliF, is one of the first steps of basal body assembly. Previous computational analysis had shown that the periplasmic region of FliF consists of three structurally similar domains, termed Ring-Building Motif (RBM)1, RBM2 and RBM3. The structure of the MS-ring has been reported recently, and unexpectedly shown that these three domains adopt different symmetries, with RBM3 having a 34-mer stoichiometry, while RBM2 adopts two distinct positions in the complex, including a 23-mer ring. This observation raises some important question on the assembly of the MS ring, and the formation of this symmetry mis-match within a single protein. In this study, we analyze the oligomerization of the individual RBM domains in isolation, in the Salmonella typhimurium FliF orthologue. We demonstrate that the periplasmic domain of FliF assembles into the MS ring, in the absence of the trans-membrane helices. We also report that the RBM2 and RBM3 domains oligomerize into ring structures, but not RBM1. Intriguingly, we observe that a construct encompassing RBM1 and RBM2 is monomeric, suggesting that RBM1 interacts with RBM2, and inhibits its oligomerization. However, this inhibition is lifted by the addition of RBM3. Collectively, this data suggests a mechanism for the controlled assembly of the MS ring.

In Situ Studies of Molecular Self-Assembling during the Formation of Ion-Conducting Membranes for Fuel Cells

2015 ◽  
Vol 792 ◽  
pp. 623-628 ◽  
Author(s):  
Kseniia N. Grafskaia ◽  
Denis V. Anokhin ◽  
Jaime J. Hernandez Rueda ◽  
Dmitriy A. Ivanov
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Molecular Architecture ◽  
Self Assembling ◽  
Ion Conducting ◽  
Microscopy Data ◽  
Conducting Membranes ◽  
Green Fuel ◽  
Synchrotron Beamlines

In present work a new setup for in situ studies of molecular self-assembling process for fabrication of ion-conducting membranes for “green” fuel cells was developed. Due to compactness, this unique setup can be used on the synchrotron beamlines. The GISAXS and optical microscopy data have shown the effectiveness of the control of molecular architecture by impact of high temperature, UV-irradiation and solvent vapors.

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.

Tandem Molecular Self-assembly for Selective Lung Cancer Therapy with Two Orders of Magnitude Increase in Efficiency

Nanoscale ◽  
2021 ◽  
Author(s):  
Debin Zheng ◽  
Jingfei Liu ◽  
Yinghao Ding ◽  
Limin Xie ◽  
Yingying Zhang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Therapy ◽  
Anticancer Drugs ◽  
Self Assembly ◽  
Therapeutic Efficacy ◽  
Self Assembling ◽  
Lung Cancer Therapy ◽  
Magnitude Increase

In situ self-assembling of prodrug molecules into nanomedicine can elevate the therapeutic efficacy of anticancer medications by enhancing the targeting and enrichment of anticancer drugs at tumor sites. However, the...

Effect of self-assembling WC film upon diamond on adhesion strength with Fe-Co-Ni binder: In situ TEM tensile tests

2022 ◽  
Vol 208 ◽  
pp. 114331
Author(s):  
P.A. Loginov ◽  
A.A. Zaitsev ◽  
D.A. Sidorenko ◽  
E.A. Levashov
Keyword(s):  
Adhesion Strength ◽  
Tensile Tests ◽  
In Situ Tem ◽  
Self Assembling

scholarly journals Mitochondria-Targeted Self-Assembly of Peptide-Based Nanomaterials

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhen Luo ◽  
Yujuan Gao ◽  
Zhongyu Duan ◽  
Yu Yi ◽  
Hao Wang
Keyword(s):  
Clinical Trials ◽  
Cancer Therapy ◽  
Self Assembly ◽  
Recent Progress ◽  
Assembly Systems ◽  
Targeted Cancer Therapy ◽  
Cancer Treatments ◽  
Self Assembling ◽  
Stimuli Response

Mitochondria are well known to serve as the powerhouse for cells and also the initiator for some vital signaling pathways. A variety of diseases are discovered to be associated with the abnormalities of mitochondria, including cancers. Thus, targeting mitochondria and their metabolisms are recognized to be promising for cancer therapy. In recent years, great efforts have been devoted to developing mitochondria-targeted pharmaceuticals, including small molecular drugs, peptides, proteins, and genes, with several molecular drugs and peptides enrolled in clinical trials. Along with the advances of nanotechnology, self-assembled peptide-nanomaterials that integrate the biomarker-targeting, stimuli-response, self-assembly, and therapeutic effect, have been attracted increasing interest in the fields of biotechnology and nanomedicine. Particularly, in situ mitochondria-targeted self-assembling peptides that can assemble on the surface or inside mitochondria have opened another dimension for the mitochondria-targeted cancer therapy. Here, we highlight the recent progress of mitochondria-targeted peptide-nanomaterials, especially those in situ self-assembly systems in mitochondria, and their applications in cancer treatments.

scholarly journals Structural insights into flagellar stator–rotor interactions

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Yunjie Chang ◽  
Ki Hwan Moon ◽  
Xiaowei Zhao ◽  
Steven J Norris ◽  
MD A Motaleb ◽  
...  
Keyword(s):  
Conformational Change ◽  
High Speed ◽  
Electron Tomography ◽  
Deletion Mutants ◽  
Flagellar Motor ◽  
Wild Type ◽  
Cryo Electron Tomography ◽  
Flagellar Filament ◽  
Structural Insights

The bacterial flagellar motor is a molecular machine that can rotate the flagellar filament at high speed. The rotation is generated by the stator–rotor interaction, coupled with an ion flux through the torque-generating stator. Here we employed cryo-electron tomography to visualize the intact flagellar motor in the Lyme disease spirochete, Borrelia burgdorferi. By analyzing the motor structures of wild-type and stator-deletion mutants, we not only localized the stator complex in situ, but also revealed the stator–rotor interaction at an unprecedented detail. Importantly, the stator–rotor interaction induces a conformational change in the flagella C-ring. Given our observation that a non-motile mutant, in which proton flux is blocked, cannot generate the similar conformational change, we propose that the proton-driven torque is responsible for the conformational change required for flagellar rotation.

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