Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch
ABSTRACT The cytoplasmic ring (C-ring) of the bacterial flagellar motor controls the motor rotation direction, thereby controlling bacterial run-and-tumble behavior. The C-ring has been shown to undergo adaptive remodeling in response to changes in motor directional bias. However, the stoichiometry...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2023-04-01
|
| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mbio.00189-23 |
| _version_ | 1797839602830016512 |
|---|---|
| author | Antai Tao Guangzhe Liu Rongjing Zhang Junhua Yuan |
| author_facet | Antai Tao Guangzhe Liu Rongjing Zhang Junhua Yuan |
| author_sort | Antai Tao |
| collection | DOAJ |
| description | ABSTRACT The cytoplasmic ring (C-ring) of the bacterial flagellar motor controls the motor rotation direction, thereby controlling bacterial run-and-tumble behavior. The C-ring has been shown to undergo adaptive remodeling in response to changes in motor directional bias. However, the stoichiometry and arrangement of the C-ring is still unclear due to contradiction between the results from fluorescence studies and cryo-electron microscopy (cryo-EM) structural analysis. Here, by using the copy number of FliG molecules (34) in the C-ring as a reference, we precisely measured the copy numbers of FliM molecules in motors rotating exclusively counterclockwise (CCW) and clockwise (CW). We surprisingly found that there are on average 45 and 58 FliM molecules in CW and CCW rotating motors, respectively, which are much higher than previous estimates. Our results suggested a new mechanism of C-ring adaptation, that is, extra FliM molecules could be bound to the primary C-ring with probability depending on the motor rotational direction. We further confirmed that all of the FliM molecules in the C-ring function in chemotaxis signaling transduction because all of them could be bound by the chemotactic response regulator CheY-P. Our measurements provided new insights into the structure and arrangement of the flagellar switch. IMPORTANCE The bacterial flagellar switch can undergo adaptive remodeling in response to changes in motor rotation direction, thereby shifting its operating point to match the output of the chemotaxis signaling pathway. However, it remains unclear how the flagellar switch accomplishes this adaptive remodeling. Here, via precise fluorescence studies, we measured the absolute copy numbers of the critical component in the switch for motors rotating counterclockwise and clockwise, obtaining much larger numbers than previous relative estimates. Our results suggested a new mechanism of adaptive remodeling of the flagellar switch and provided new insights for updating the conformation spread model of the switch. |
| first_indexed | 2024-04-09T15:59:29Z |
| format | Article |
| id | doaj.art-567516f2704f430f833371757c5cfd95 |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-04-09T15:59:29Z |
| publishDate | 2023-04-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-567516f2704f430f833371757c5cfd952023-04-25T13:04:57ZengAmerican Society for MicrobiologymBio2150-75112023-04-0114210.1128/mbio.00189-23Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar SwitchAntai Tao0Guangzhe Liu1Rongjing Zhang2Junhua Yuan3Department of Physics, University of Science and Technology of China, Hefei, Anhui, ChinaWenzhou Institute, University of Chinese Academy of Science, Wenzhou, Zhejiang, P.R. ChinaDepartment of Physics, University of Science and Technology of China, Hefei, Anhui, ChinaDepartment of Physics, University of Science and Technology of China, Hefei, Anhui, ChinaABSTRACT The cytoplasmic ring (C-ring) of the bacterial flagellar motor controls the motor rotation direction, thereby controlling bacterial run-and-tumble behavior. The C-ring has been shown to undergo adaptive remodeling in response to changes in motor directional bias. However, the stoichiometry and arrangement of the C-ring is still unclear due to contradiction between the results from fluorescence studies and cryo-electron microscopy (cryo-EM) structural analysis. Here, by using the copy number of FliG molecules (34) in the C-ring as a reference, we precisely measured the copy numbers of FliM molecules in motors rotating exclusively counterclockwise (CCW) and clockwise (CW). We surprisingly found that there are on average 45 and 58 FliM molecules in CW and CCW rotating motors, respectively, which are much higher than previous estimates. Our results suggested a new mechanism of C-ring adaptation, that is, extra FliM molecules could be bound to the primary C-ring with probability depending on the motor rotational direction. We further confirmed that all of the FliM molecules in the C-ring function in chemotaxis signaling transduction because all of them could be bound by the chemotactic response regulator CheY-P. Our measurements provided new insights into the structure and arrangement of the flagellar switch. IMPORTANCE The bacterial flagellar switch can undergo adaptive remodeling in response to changes in motor rotation direction, thereby shifting its operating point to match the output of the chemotaxis signaling pathway. However, it remains unclear how the flagellar switch accomplishes this adaptive remodeling. Here, via precise fluorescence studies, we measured the absolute copy numbers of the critical component in the switch for motors rotating counterclockwise and clockwise, obtaining much larger numbers than previous relative estimates. Our results suggested a new mechanism of adaptive remodeling of the flagellar switch and provided new insights for updating the conformation spread model of the switch.https://journals.asm.org/doi/10.1128/mbio.00189-23adaptive remodelingallosterybacterial motilityflagellar motor |
| spellingShingle | Antai Tao Guangzhe Liu Rongjing Zhang Junhua Yuan Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch mBio adaptive remodeling allostery bacterial motility flagellar motor |
| title | Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch |
| title_full | Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch |
| title_fullStr | Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch |
| title_full_unstemmed | Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch |
| title_short | Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch |
| title_sort | precise measurement of the stoichiometry of the adaptive bacterial flagellar switch |
| topic | adaptive remodeling allostery bacterial motility flagellar motor |
| url | https://journals.asm.org/doi/10.1128/mbio.00189-23 |
| work_keys_str_mv | AT antaitao precisemeasurementofthestoichiometryoftheadaptivebacterialflagellarswitch AT guangzheliu precisemeasurementofthestoichiometryoftheadaptivebacterialflagellarswitch AT rongjingzhang precisemeasurementofthestoichiometryoftheadaptivebacterialflagellarswitch AT junhuayuan precisemeasurementofthestoichiometryoftheadaptivebacterialflagellarswitch |