Structure of the Rotor of the Bacterial Flagellar Motor Revealed by Electron Cryomicroscopy and Single-particle Image Analysis

Suzuki, Hirofumi; Yonekura, Koji; Namba, Keiichi

doi:10.1016/j.jmb.2004.01.034

Cited by 144 publications

(127 citation statements)

References 56 publications

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“…For instance, the fliF gene is expressed in Streptococcus suis infecting piglets (254) and in Pseudomonas fluorescens colonizing sugar beet rhizosphere (78). Multiple copies (Ϸ25) of the FliF protein are assembled into the cytoplasmic membrane-embedded MSring, which constitutes the core of the flagellar motor (268). The isolation of these fliF genes indicates that the flagellar machinery is important for gram-positive as well as for gramnegative bacteria to establish interactions with both animal and plant hosts.…”

Section: Overview Of Ivet-and Dfi-isolated Genesmentioning

confidence: 99%

Unraveling the Secret Lives of Bacteria: Use of In Vivo Expression Technology and Differential Fluorescence Induction Promoter Traps as Tools for Exploring Niche-Specific Gene Expression

Rediers

Rainey

Vanderleyden

et al. 2005

Microbiol Mol Biol Rev

140

120

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A major challenge for microbiologists is to elucidate the strategies deployed by microorganisms to adapt to and thrive in highly complex and dynamic environments. In vitro studies, including those monitoring genomewide changes, have proven their value, but they can, at best, mimic only a subset of the ensemble of abiotic and biotic stimuli that microorganisms experience in their natural habitats. The widely used gene-to-phenotype approach involves the identification of altered niche-related phenotypes on the basis of gene inactivation. However, many traits contributing to ecological performance that, upon inactivation, result in only subtle or difficult to score phenotypic changes are likely to be overlooked by this otherwise powerful approach. Based on the premise that many, if not most, of the corresponding genes will be induced or upregulated in the environment under study, ecologically significant genes can alternatively be traced using the promoter trap techniques differential fluorescence induction and in vivo expression technology (IVET). The potential and limitations are discussed for the different IVET selection strategies and system-specific variants thereof. Based on a compendium of genes that have emerged from these promoter-trapping studies, several functional groups have been distinguished, and their physiological relevance is illustrated with follow-up studies of selected genes. In addition to confirming results from largely complementary approaches such as signature-tagged mutagenesis, some unexpected parallels as well as distinguishing features of microbial phenotypic acclimation in diverse environmental niches have surfaced. On the other hand, by the identification of a large proportion of genes with unknown function, these promoter-trapping studies underscore how little we know about the secret lives of bacteria and other microorganisms

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Section: Overview Of Ivet-and Dfi-isolated Genesmentioning

confidence: 99%

Unraveling the Secret Lives of Bacteria: Use of In Vivo Expression Technology and Differential Fluorescence Induction Promoter Traps as Tools for Exploring Niche-Specific Gene Expression

Rediers

Rainey

Vanderleyden

et al. 2005

Microbiol Mol Biol Rev

140

120

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“…The motor is about is about 45 nm in diameter and is composed of at least 13 different proteins, all in different copy numbers. It is powered by a transmembrane ion flux (1,3,4) and consists of a core rotating against a ring of stator proteins (1,(5)(6)(7). The C ring, also called the "switch complex," is part of the rotor and localized to the cytoplasmic motor region.…”

mentioning

confidence: 99%

Signal-dependent turnover of the bacterial flagellar switch protein FliM

Delalez

Wadhams

Rosser

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

178

181

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Most biological processes are performed by multiprotein complexes. Traditionally described as static entities, evidence is now emerging that their components can be highly dynamic, exchanging constantly with cellular pools. The bacterial flagellar motor contains ∼13 different proteins and provides an ideal system to study functional molecular complexes. It is powered by transmembrane ion flux through a ring of stator complexes that push on a central rotor. The Escherichia coli motor switches direction stochastically in response to binding of the response regulator CheY to the rotor switch component FliM. Much is known of the static motor structure, but we are just beginning to understand the dynamics of its individual components. Here we measure the stoichiometry and turnover of FliM in functioning flagellar motors, by using high-resolution fluorescence microscopy of E. coli expressing genomically encoded YPet derivatives of FliM at physiological levels. We show that the ∼30 FliM molecules per motor exist in two discrete populations, one tightly associated with the motor and the other undergoing stochastic turnover. This turnover of FliM molecules depends on the presence of active CheY, suggesting a potential role in the process of motor switching. In many ways the bacterial flagellar motor is as an archetype macromolecular assembly, and our results may have further implications for the functional relevance of protein turnover in other large molecular complexes.chemotaxis | single molecule | total internal reflection fluorescence | in vivo microscopy | molecular motor T he bacterial flagellar motor is one of the most complex biological nanomachines (1), ideal for investigating turnover within a multimeric complex. It is the result of the coordinated, sequential expression of about 50 genes (2) producing a structure that spans the cell membrane and rotates an extracellular filament extending several micrometers from the cell surface, at speed of hundreds of hertz. The motor is about is about 45 nm in diameter and is composed of at least 13 different proteins, all in different copy numbers. It is powered by a transmembrane ion flux (1, 3, 4) and consists of a core rotating against a ring of stator proteins (1, 5-7). The C ring, also called the "switch complex," is part of the rotor and localized to the cytoplasmic motor region. The response regulator CheY-P binds one of the C ring components, FliM, causing the rotor to switch rotational direction, thus making FliM the interface with the chemosensory pathway (8-11).Much is known of the static motor structure (5-7), but the dynamics and interactions of its constituents under natural conditions in living cells are poorly understood. Recent results showed that molecules of the stator protein MotB in the flagellar motor, fused to GFP, exchange with a membrane pool of freely diffusing MotB on a time scale of minutes (12)(13)(14). This observation raised the question of whether protein turnover is a general feature of molecular complexes or is a peculiarity of MotB.To ad...

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“…The previous observation of 26 CCW steps per revolution of the flagellar motor (20), which corresponds to the number of FliG subunits that form part of the rotor ring (21), made it clear that the elementary torque generation process is the cyclic association/dissociation of the stator complex MotA/B with every FliG subunit along the circumference of the rotor. The observation of such a fine stepping motion was made possible by reducing the number of functional stators in the sodium ion-driven chimeric flagellar motor and lowering sodium ion motive force to reduce the rotation rate to meet the spatial and temporal resolution of the measurement system (20).…”

mentioning

confidence: 99%

Evidence for symmetry in the elementary process of bidirectional torque generation by the bacterial flagellar motor

Nakamura

Kami-ike

Yokota

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The bacterial flagellar motor can rotate in both counterclockwise (CCW) and clockwise (CW) directions. It has been shown that the sodium ion-driven chimeric flagellar motor rotates with 26 steps per revolution, which corresponds to the number of FliG subunits that form part of the rotor ring, but the size of the backward step is smaller than the forward one. Here we report that the protondriven flagellar motor of Salmonella also rotates with 26 steps per revolution but symmetrical in both CCW and CW directions with occasional smaller backward steps in both directions. Occasional shift in the stepping positions is also observed, suggesting the frequent exchange of stators in one of the 11-12 possible anchoring positions around the rotor. These observations indicate that the elementary process of torque generation by the cyclic association/ dissociation of the stator with every FliG subunit along the circumference of the rotor is symmetric in CCW and CW rotation even though the structure of FliG is highly asymmetric and suggests a 180°rotation of a FliG domain for the rotor-stator interaction to reverse the direction of rotation.FliG | MotAB stator complex | Salmonella | stepping rotation | switch

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Structure of the Rotor of the Bacterial Flagellar Motor Revealed by Electron Cryomicroscopy and Single-particle Image Analysis

Cited by 144 publications

References 56 publications

Unraveling the Secret Lives of Bacteria: Use of In Vivo Expression Technology and Differential Fluorescence Induction Promoter Traps as Tools for Exploring Niche-Specific Gene Expression

Unraveling the Secret Lives of Bacteria: Use of In Vivo Expression Technology and Differential Fluorescence Induction Promoter Traps as Tools for Exploring Niche-Specific Gene Expression

Signal-dependent turnover of the bacterial flagellar switch protein FliM

Evidence for symmetry in the elementary process of bidirectional torque generation by the bacterial flagellar motor

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