Elastic coupling power stroke mechanism of the F1-ATPase molecular motor
The angular velocity profile of the 120° F1-ATPase power stroke was resolved as a function of temperature from 16.3 to 44.6 °C using a ΔμATP = −31.25 kBT at a time resolution of 10 μs. Angular velocities during the first 60° of the power stroke (phase 1) varied inversely with temperature, resulting...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Sprog: | English |
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National Academy of Sciences
2018
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| _version_ | 1826310544739532800 |
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| author | Martin, JL Ishmukhametov, R Spetzler, D Hornung, T Frasch, WD |
| author_facet | Martin, JL Ishmukhametov, R Spetzler, D Hornung, T Frasch, WD |
| author_sort | Martin, JL |
| collection | OXFORD |
| description | The angular velocity profile of the 120° F1-ATPase power stroke was resolved as a function of temperature from 16.3 to 44.6 °C using a ΔμATP = −31.25 kBT at a time resolution of 10 μs. Angular velocities during the first 60° of the power stroke (phase 1) varied inversely with temperature, resulting in negative activation energies with a parabolic dependence. This is direct evidence that phase 1 rotation derives from elastic energy (spring constant, κ = 50 kBT·rad−2). Phase 2 of the power stroke had an enthalpic component indicating that additional energy input occurred to enable the γ-subunit to overcome energy stored by the spring after rotating beyond its 34° equilibrium position. The correlation between the probability distribution of ATP binding to the empty catalytic site and the negative Ea values of the power stroke during phase 1 suggests that this additional energy is derived from the binding of ATP to the empty catalytic site. A second torsion spring (κ = 150 kBT·rad−2; equilibrium position, 90°) was also evident that mitigated the enthalpic cost of phase 2 rotation. The maximum ΔGǂ was 22.6 kBT, and maximum efficiency was 72%. An elastic coupling mechanism is proposed that uses the coiled-coil domain of the γ-subunit rotor as a torsion spring during phase 1, and then as a crankshaft driven by ATP-binding–dependent conformational changes during phase 2 to drive the power stroke. |
| first_indexed | 2024-03-07T07:53:32Z |
| format | Journal article |
| id | oxford-uuid:cc1bff89-270c-41e8-b3e2-fab59e3648b5 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:53:32Z |
| publishDate | 2018 |
| publisher | National Academy of Sciences |
| record_format | dspace |
| spelling | oxford-uuid:cc1bff89-270c-41e8-b3e2-fab59e3648b52023-08-04T09:04:13ZElastic coupling power stroke mechanism of the F1-ATPase molecular motorJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:cc1bff89-270c-41e8-b3e2-fab59e3648b5EnglishSymplectic ElementsNational Academy of Sciences2018Martin, JLIshmukhametov, RSpetzler, DHornung, TFrasch, WDThe angular velocity profile of the 120° F1-ATPase power stroke was resolved as a function of temperature from 16.3 to 44.6 °C using a ΔμATP = −31.25 kBT at a time resolution of 10 μs. Angular velocities during the first 60° of the power stroke (phase 1) varied inversely with temperature, resulting in negative activation energies with a parabolic dependence. This is direct evidence that phase 1 rotation derives from elastic energy (spring constant, κ = 50 kBT·rad−2). Phase 2 of the power stroke had an enthalpic component indicating that additional energy input occurred to enable the γ-subunit to overcome energy stored by the spring after rotating beyond its 34° equilibrium position. The correlation between the probability distribution of ATP binding to the empty catalytic site and the negative Ea values of the power stroke during phase 1 suggests that this additional energy is derived from the binding of ATP to the empty catalytic site. A second torsion spring (κ = 150 kBT·rad−2; equilibrium position, 90°) was also evident that mitigated the enthalpic cost of phase 2 rotation. The maximum ΔGǂ was 22.6 kBT, and maximum efficiency was 72%. An elastic coupling mechanism is proposed that uses the coiled-coil domain of the γ-subunit rotor as a torsion spring during phase 1, and then as a crankshaft driven by ATP-binding–dependent conformational changes during phase 2 to drive the power stroke. |
| spellingShingle | Martin, JL Ishmukhametov, R Spetzler, D Hornung, T Frasch, WD Elastic coupling power stroke mechanism of the F1-ATPase molecular motor |
| title | Elastic coupling power stroke mechanism of the F1-ATPase molecular motor |
| title_full | Elastic coupling power stroke mechanism of the F1-ATPase molecular motor |
| title_fullStr | Elastic coupling power stroke mechanism of the F1-ATPase molecular motor |
| title_full_unstemmed | Elastic coupling power stroke mechanism of the F1-ATPase molecular motor |
| title_short | Elastic coupling power stroke mechanism of the F1-ATPase molecular motor |
| title_sort | elastic coupling power stroke mechanism of the f1 atpase molecular motor |
| work_keys_str_mv | AT martinjl elasticcouplingpowerstrokemechanismofthef1atpasemolecularmotor AT ishmukhametovr elasticcouplingpowerstrokemechanismofthef1atpasemolecularmotor AT spetzlerd elasticcouplingpowerstrokemechanismofthef1atpasemolecularmotor AT hornungt elasticcouplingpowerstrokemechanismofthef1atpasemolecularmotor AT fraschwd elasticcouplingpowerstrokemechanismofthef1atpasemolecularmotor |