The myosin motor in muscle generates a smaller and slower working stroke at higher load

M Reconditi; M Linari; L Lucii; A Stewart; Y B Sun; P Boesecke; T Narayanan; R F Fischetti; T Irving; G Piazzesi; M Irving; V Lombardi

doi:10.1038/nature02380

The myosin motor in muscle generates a smaller and slower working stroke at higher load

M Reconditi, M Linari, L Lucii, A Stewart, Y B Sun, P Boesecke, T Narayanan, R F Fischetti, T Irving, G Piazzesi, M Irving, V Lombardi

Research output: Contribution to journal › Article › peer-review

167 Citations (Scopus)

Abstract

Muscle contraction is driven by the motor protein myosin II, which binds transiently to an actin filament, generates a unitary filament displacement or 'working stroke', then detaches and repeats the cycle. The stroke size has been measured previously using isolated myosin II molecules at low load, with rather variable results(1-4), but not at the higher loads that the motor works against during muscle contraction. Here we used a novel X-ray-interference technique(5,6) to measure the working stroke of myosin II at constant load(7) in an intact muscle cell, preserving the native structure and function of the motor. We show that the stroke is smaller and slower at higher load. The stroke size at low load is likely to be set by a structural limit(8,9); at higher loads, the motor detaches from actin before reaching this limit. The load dependence of the myosin II stroke is the primary molecular determinant of the mechanical performance and efficiency of skeletal muscle.

Original language	English
Pages (from-to)	578 - 581
Number of pages	4
Journal	NATURE
Volume	428
Issue number	6982
DOIs	https://doi.org/10.1038/nature02380
Publication status	Published - 1 Apr 2004

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abstract = "Muscle contraction is driven by the motor protein myosin II, which binds transiently to an actin filament, generates a unitary filament displacement or 'working stroke', then detaches and repeats the cycle. The stroke size has been measured previously using isolated myosin II molecules at low load, with rather variable results(1-4), but not at the higher loads that the motor works against during muscle contraction. Here we used a novel X-ray-interference technique(5,6) to measure the working stroke of myosin II at constant load(7) in an intact muscle cell, preserving the native structure and function of the motor. We show that the stroke is smaller and slower at higher load. The stroke size at low load is likely to be set by a structural limit(8,9); at higher loads, the motor detaches from actin before reaching this limit. The load dependence of the myosin II stroke is the primary molecular determinant of the mechanical performance and efficiency of skeletal muscle.",

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T1 - The myosin motor in muscle generates a smaller and slower working stroke at higher load

AU - Reconditi, M

AU - Linari, M

AU - Lucii, L

AU - Stewart, A

AU - Sun, Y B

AU - Boesecke, P

AU - Narayanan, T

AU - Fischetti, R F

AU - Irving, T

AU - Piazzesi, G

AU - Irving, M

AU - Lombardi, V

PY - 2004/4/1

Y1 - 2004/4/1

N2 - Muscle contraction is driven by the motor protein myosin II, which binds transiently to an actin filament, generates a unitary filament displacement or 'working stroke', then detaches and repeats the cycle. The stroke size has been measured previously using isolated myosin II molecules at low load, with rather variable results(1-4), but not at the higher loads that the motor works against during muscle contraction. Here we used a novel X-ray-interference technique(5,6) to measure the working stroke of myosin II at constant load(7) in an intact muscle cell, preserving the native structure and function of the motor. We show that the stroke is smaller and slower at higher load. The stroke size at low load is likely to be set by a structural limit(8,9); at higher loads, the motor detaches from actin before reaching this limit. The load dependence of the myosin II stroke is the primary molecular determinant of the mechanical performance and efficiency of skeletal muscle.

AB - Muscle contraction is driven by the motor protein myosin II, which binds transiently to an actin filament, generates a unitary filament displacement or 'working stroke', then detaches and repeats the cycle. The stroke size has been measured previously using isolated myosin II molecules at low load, with rather variable results(1-4), but not at the higher loads that the motor works against during muscle contraction. Here we used a novel X-ray-interference technique(5,6) to measure the working stroke of myosin II at constant load(7) in an intact muscle cell, preserving the native structure and function of the motor. We show that the stroke is smaller and slower at higher load. The stroke size at low load is likely to be set by a structural limit(8,9); at higher loads, the motor detaches from actin before reaching this limit. The load dependence of the myosin II stroke is the primary molecular determinant of the mechanical performance and efficiency of skeletal muscle.

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The myosin motor in muscle generates a smaller and slower working stroke at higher load

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