Enhanced force generation by smooth muscle myosin in vitro.
AUTOR(ES)
VanBuren, P
RESUMO
To determine whether the apparent enhanced force-generating capabilities of smooth muscle relative to skeletal muscle are inherent to the myosin cross-bridge, the isometric steady-state force produced by myosin in the in vitro motility assay was measured. In this assay, myosin adhered to a glass surface pulls on an actin filament that is attached to an ultracompliant (50-200 nm/pN) glass microneedle. The number of myosin cross-bridge heads able to interact with a length of actin filament was estimated by measuring the density of biochemically active myosin adhered to the surface; with this estimate, the average force per cross-bridge head of smooth and skeletal muscle myosins is 0.6 pN and 0.2 pN, respectively. Surprisingly, smooth muscle myosin generates approximately three times greater average force per cross-bridge head than does skeletal muscle myosin.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=42914Documentos Relacionados
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