Skeletal muscle myosin light chains are essential for physiological speeds of shortening.
Nature
; 365(6445): 454-6, 1993 Sep 30.
Article
em En
| MEDLINE
| ID: mdl-8413589
ABSTRACT
In muscle each myosin head contains a regulatory light chain (LC2) that is wrapped around the head/rod junction, and an alkali light chain that is distal to LC2 (ref. 1). The role of these light chains in vertebrate skeletal muscle myosin has remained obscure. Here we prepare heavy chains that are free of both light chains in order to determine by a motility assay whether the light chains are necessary for movement. We find that removal of light chains from myosin reduces the velocity of actin filaments from 8.8 microns s-1 to 0.8 microns s-1 without significantly decreasing the ATPase activity. Reconstitution of myosin with LC2 or alkali light chain increases filament velocity to intermediate rates, and readdition of both classes of light chains fully restores the original sliding velocity. We conclude that even though the light chains are not essential for enzymatic activity, light-chain/heavy-chain interactions play an important part in the conversion of chemical energy into movement.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Miosinas
/
Contração Muscular
Limite:
Animals
Idioma:
En
Revista:
Nature
Ano de publicação:
1993
Tipo de documento:
Article