Ensemble velocity of non-processive molecular motors with multiple chemical states

Vilfan, Andrej

doi:10.1098/rsfs.2014.0032

Cited by 4 publications

(4 citation statements)

References 51 publications

(73 reference statements)

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“…1(a), each cross-linking motor molecule is represented by a spring tethered to a bottom surface and a motor, which can bind to the MT and walk along it. Therefore, the motor not only produces a force-generating stroke, but also moves via a random walk along the filament, which is the major difference between this model and previous models of motor-filament systems915161718. Under such a situation, we consider if and how the motor’s directionality switches as N increases, as illustrated in Fig.…”

Section: Modelmentioning

confidence: 99%

Embedding dual function into molecular motors through collective motion

Saito

Kaneko

2017

Sci Rep

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Protein motors, such as kinesins and dyneins, bind to a microtubule and travel along it in a specific direction. Previously, it was thought that the directionality for a given motor was constant in the absence of an external force. However, the directionality of the kinesin-5 Cin8 was recently found to change as the number of motors that bind to the same microtubule is increased. Here, we introduce a simple mechanical model of a microtubule-sliding assay in which multiple motors interact with the filament. We show that, due to the collective phenomenon, the directionality of the motor changes (e.g., from minus- to plus- end directionality), depending on the number of motors. This is induced by a large diffusive component in the directional walk and by the subsequent frustrated motor configuration, in which multiple motors pull the filament in opposite directions, similar to a game of tug-of-war. A possible role of the dual-directional motors for the mitotic spindle formation is also discussed. Our framework provides a general mechanism to embed two conflicting tasks into a single molecular machine, which works context-dependently.

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Section: Modelmentioning

confidence: 99%

Embedding dual function into molecular motors through collective motion

Saito

Kaneko

2017

Sci Rep

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“…The unloaded velocity is maximal when the first transition is fast k 1 → ∞ and contains the full working stroke ( d 1 = d , ), with the remaining transitions having equal rate constants . It has the value , where [ 48 ]. The maximum force per motor is Kdt on / t cycle , while the ATPase rate is always 1/ t cycle .…”

Section: Resultsmentioning

confidence: 99%

“…The unloaded velocity is maximal when the first transition is fast k 1 ! 1 and contains the full working stroke ( [48]. The maximum force per motor is Kdt on /t cycle , while the ATPase rate is always 1/t cycle .…”

Section: Velocity-independent Maximum Efficiencymentioning

confidence: 99%

Theoretical efficiency limits and speed-efficiency trade-off in myosin motors

Vilfan

Šarlah

2023

PLoS Comput Biol

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Muscle myosin is a non-processive molecular motor generates mechanical work when cooperating in large ensembles. During its cyle, each individual motor keeps attaching and detaching from the actin filament. The random nature of attachment and detachment inevitably leads to losses and imposes theoretical limits on the energetic efficiency. Here, we numerically determine the theoretical efficiency limit of a classical myosin model with a given number of mechano-chemical states. All parameters that are not bounded by physical limits (like rate limiting steps) are determined by numerical efficiency optimization. We show that the efficiency is limited by the number of states, the stiffness and the rate-limiting kinetic steps. There is a trade-off between speed and efficiency. Slow motors are optimal when most of the available free energy is allocated to the working stroke and the stiffness of their elastic element is high. Fast motors, on the other hand, work better with a lower and asymmetric stiffness and allocate a larger fraction of free energy to the release of ADP. Overall, many features found in myosins coincide with the findings from the model optimization: there are at least 3 bound states, the largest part of the working stroke takes place during the first transition, the ADP affinity is adapted differently in slow and fast myosins and there is an asymmetry in elastic elements.

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“…Moving to the physics of molecular motors and the cytoskeleton, Vilfan [7] discusses the velocity of large ensembles of non-processive molecular motors. Considering a general model, he demonstrates that the ensemble velocity can have an interesting ATP dependence that reveals features of the underlying chemical scheme.…”

mentioning

confidence: 99%