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Autores principales: McGrath, Jake, Kent, Brian, Johnson, Colin, Alvarado, José
Formato: Preprint
Publicado: 2024
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Acceso en línea:https://arxiv.org/abs/2411.02340
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author McGrath, Jake
Kent, Brian
Johnson, Colin
Alvarado, José
author_facet McGrath, Jake
Kent, Brian
Johnson, Colin
Alvarado, José
contents Myosin motors are fundamental biological actuators, powering diverse mechanical tasks in eukaryotic cells via ATP hydrolysis. Recent work revealed that myosin's velocity-dependent detachment rate can bridge actomyosin dynamics to macroscale Hill muscle predictions. However, the influence of this microscale unbinding, which we characterize by a dimensionless parameter $α$, on macroscale energetic flows-such as power consumption, output and efficiency-remains elusive. Here we develop an analytical model of myosin dynamics that relates unbinding rates $α$ to energetics. Our model agrees with published in-vivo muscle data and, furthermore, uncovers a performance-efficiency tradeoff governed by $α$. To experimentally validate the tradeoff, we build HillBot, a robophysical model of Hill's muscle that mimics nonlinearity. Through HillBot, we decouple $α$'s concurrent effect on performance and efficiency, demonstrating that nonlinearity drives efficiency. We compile 136 published measurements of $α$ in muscle and myoblasts to reveal a distribution centered at $α^* = 3.85 \pm 2.32$. Synthesizing data from our model and HillBot, we quantitatively show that $α^*$ corresponds to a class of generalist actuators that are both relatively powerful and efficient, suggesting that the performance-efficiency tradeoff underpins the prevalence of $α^*$ in nature. We leverage these insights and propose a nonlinear variable-impedance protocol to shift along a performance-efficiency axis in robotic applications.
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institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Microscale velocity-dependent unbinding generates a macroscale performance-efficiency tradeoff in actomyosin systems
McGrath, Jake
Kent, Brian
Johnson, Colin
Alvarado, José
Biological Physics
Myosin motors are fundamental biological actuators, powering diverse mechanical tasks in eukaryotic cells via ATP hydrolysis. Recent work revealed that myosin's velocity-dependent detachment rate can bridge actomyosin dynamics to macroscale Hill muscle predictions. However, the influence of this microscale unbinding, which we characterize by a dimensionless parameter $α$, on macroscale energetic flows-such as power consumption, output and efficiency-remains elusive. Here we develop an analytical model of myosin dynamics that relates unbinding rates $α$ to energetics. Our model agrees with published in-vivo muscle data and, furthermore, uncovers a performance-efficiency tradeoff governed by $α$. To experimentally validate the tradeoff, we build HillBot, a robophysical model of Hill's muscle that mimics nonlinearity. Through HillBot, we decouple $α$'s concurrent effect on performance and efficiency, demonstrating that nonlinearity drives efficiency. We compile 136 published measurements of $α$ in muscle and myoblasts to reveal a distribution centered at $α^* = 3.85 \pm 2.32$. Synthesizing data from our model and HillBot, we quantitatively show that $α^*$ corresponds to a class of generalist actuators that are both relatively powerful and efficient, suggesting that the performance-efficiency tradeoff underpins the prevalence of $α^*$ in nature. We leverage these insights and propose a nonlinear variable-impedance protocol to shift along a performance-efficiency axis in robotic applications.
title Microscale velocity-dependent unbinding generates a macroscale performance-efficiency tradeoff in actomyosin systems
topic Biological Physics
url https://arxiv.org/abs/2411.02340