Mutational Analyses Define Helix Organization and Key Residues of a Bacterial Membrane Energy-transducing Complex

Goemaere, Emilie L.; Cascales, Éric; Lloubès, Roland

doi:10.1016/j.jmb.2006.12.020

Cited by 53 publications

(79 citation statements)

References 59 publications

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“…␤3a and ␤3b curve around the ␤-barrel at almost 90 o to each other. ␤3b is connected to another long strand, ␤4 (53)(54)(55)(56)(57)(58)(59)(60)(61)(62), by a type I hairpin turn. The ␤3␤4 hairpin extends away from the top of the ␤-barrel.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structures of a CTXφ pIII Domain Unbound and in Complex with a Vibrio cholerae TolA Domain Reveal Novel Interaction Interfaces

Ford

Kolappan

Phan

et al. 2012

Journal of Biological Chemistry

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Background: CTX infection of Vibrio cholerae confers toxigenicity. Results: We report crystal structures of CTX-pIII domain N1 alone and bound to V. cholerae TolA domain C. Conclusion: CTX and coliphage pIII use distinct mechanisms to bind to TolA. Significance: These structures contribute to our understanding of a critical step in the evolution of pandemic V. cholerae with implications for emerging V. cholerae pathogens.

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Section: Resultsmentioning

confidence: 99%

Crystal Structures of a CTXφ pIII Domain Unbound and in Complex with a Vibrio cholerae TolA Domain Reveal Novel Interaction Interfaces

Ford

Kolappan

Phan

et al. 2012

Journal of Biological Chemistry

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“…This modification of TolA conformation has been shown by limited protease accessibility to be dependent upon PMF, TolQ, TolR, and a conserved motif within the TolA inner membrane anchor (14). Recently, we demonstrated that residues conserved on specific faces of the TolQ and TolR TMHs constitute a putative ion pathway, probably responsible for binding and releasing ions or protons (5). These residues are conserved within the TolQ or TolR protein families but also in the homologous ExbB or ExbD and the orthologous MotA or MotB proteins (4,5).…”

mentioning

confidence: 89%

“…TolQ and TolR are two accessory proteins interacting with TolA in the inner membrane. Based on sequence comparisons and effects of amino acids substitutions, TolQR have been proposed to form a proton or ion channel, which converts PMF to mechanical energy (4,5). TolQ is an integral inner membrane protein, with three transmembrane-spanning helices (TMHs) (6,7).…”

mentioning

confidence: 99%

“…TolQ and TolR proteins interact in the membrane through their TMHs in a 4:2 stoichiometry (4,9,10,11,12,13). It has been proposed that ion or proton flow at the interface of the TMHs of the TolQR complex regulates structural modifications within this complex and hence results in a conformational change within TolA (3)(4)(5). This modification of TolA conformation has been shown by limited protease accessibility to be dependent upon PMF, TolQ, TolR, and a conserved motif within the TolA inner membrane anchor (14).…”

mentioning

confidence: 99%

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Movements of the TolR C-terminal Domain Depend on TolQR Ionizable Key Residues and Regulate Activity of the Tol Complex

Goemaere

Devert

Lloubès

et al. 2007

Journal of Biological Chemistry

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The TolQRA proteins of Escherichia coli form an inner membrane complex involved in the maintenance of the outer membrane stability and in the late stages of cell division. The TolQR complex uses the proton-motive force to regulate TolA conformation and its interaction with the outer membrane Pal lipoprotein. It has been proposed that an ion channel forms at the TolQR transmembrane helix interface. This complex assembles with a minimal TolQ/TolR ratio of 4:2, therefore involving at least 14 transmembrane helices, which may form the ion pathway. The C-terminal periplasmic domain of TolR protein interacts with TolQ and has been proposed to control the TolQR channel activity. Here, we constructed unique cysteine substitutions in the last 27 residues of TolR. Each of the substitutions results in a functional TolR protein. Disulfide cross-linking demonstrates that the TolQR complex is dynamic, involving conformational modifications of TolR C-terminal domain. We monitored these structural changes by cysteine accessibility experiments and showed that the conformation of this domain is responsive to the proton-motive force and on the presence of critical residues of the ion pathway.

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“…The N-terminal domain of TolB interacts with the periplasmic domain of TolA and forms an ion-conducting complex with TolQ/R (27)(28)(29). TolQ/R have sequence homology with PomA/B, and both conduct the coupling ion for their function (30,31). The C-terminal domains of MotY and PomB show structural and functional similarities with Pal (21,32).…”

Section: Terashima Et Almentioning

confidence: 99%

Insight into the assembly mechanism in the supramolecular rings of the sodium-driven Vibrio flagellar motor from the structure of FlgT

Terashima

Sakuma

et al. 2013

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

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Flagellar motility is a key factor for bacterial survival and growth in fluctuating environments. The polar flagellum of a marine bacterium, Vibrio alginolyticus, is driven by sodium ion influx and rotates approximately six times faster than the proton-driven motor of Escherichia coli. The basal body of the sodium motor has two unique ring structures, the T ring and the H ring. These structures are essential for proper assembly of the stator unit into the basal body and to stabilize the motor. FlgT, which is a flagellar protein specific for Vibrio sp., is required to form and stabilize both ring structures. Here, we report the crystal structure of FlgT at 2.0-Å resolution. FlgT is composed of three domains, the N-terminal domain (FlgT-N), the middle domain (FlgT-M), and the C-terminal domain (FlgT-C). FlgT-M is similar to the N-terminal domain of TolB, and FlgT-C resembles the N-terminal domain of FliI and the α/β subunits of F 1 -ATPase. To elucidate the role of each domain, we prepared domain deletion mutants of FlgT and analyzed their effects on the basal-body ring formation. The results suggest that FlgT-N contributes to the construction of the H-ring structure, and FlgT-M mediates the T-ring association on the LP ring. FlgT-C is not essential but stabilizes the H-ring structure. On the basis of these results, we propose an assembly mechanism for the basal-body rings and the stator units of the sodium-driven flagellar motor.X-ray crystallography | molecular motor T o find favorable conditions for survival and growth, bacteria swim by rotating their flagellum, a filamentous organelle for motility. The flagellum is a large macromolecular assembly composed of three major parts: the basal body, the hook, and the filament. The flagellar filament is driven by a rotary motor embedded in the cell membrane (1-4). The motor is powered by the electrochemical gradient of the coupling ion (H + or Na + ), which results in rotation of the filament like a screw. Whereas the proton motors of Escherichia coli and Salmonella enterica serovar Typhimurium spin up to 300 Hz, the sodium motor of Vibrio alginolyticus can rotate remarkably faster, up to 1,700 Hz (5).The flagellar motor is made of the basal body, which includes the rotor, and a dozen stator units that surround the rotor. Each stator unit is a complex of two distinct membrane proteins, A and B, with an A 4 B 2 stoichiometry. The stator is composed of PomA and PomB in the sodium driven motor of Vibrio sp., and MotA and MotB in the proton motors of E. coli and Salmonella, and they generate torque by conducting the coupling ion into the cytoplasm (6-11). Multiple stator complexes assemble around the rotor, although a single stator complex can generate torque (12-15).The basal body is a complex macromolecular assembly including several ring structures, such as the L, P, MS, and C rings, and a drive shaft, which is also called the rod (16). The L and P rings form a bushing for the rod, and the MS and C rings are a reversible rotor. The L and P rings are composed of FlgH an...

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Mutational Analyses Define Helix Organization and Key Residues of a Bacterial Membrane Energy-transducing Complex

Cited by 53 publications

References 59 publications

Crystal Structures of a CTXφ pIII Domain Unbound and in Complex with a Vibrio cholerae TolA Domain Reveal Novel Interaction Interfaces

Crystal Structures of a CTXφ pIII Domain Unbound and in Complex with a Vibrio cholerae TolA Domain Reveal Novel Interaction Interfaces

Movements of the TolR C-terminal Domain Depend on TolQR Ionizable Key Residues and Regulate Activity of the Tol Complex

Insight into the assembly mechanism in the supramolecular rings of the sodium-driven Vibrio flagellar motor from the structure of FlgT

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