Send to

Choose Destination
Biophys J. 1995 Apr;68(4 Suppl):120S-126S; discussion 126S-127S.

Role of skeletal and smooth muscle myosin light chains.

Author information

Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254-9110, USA.


A persistent problem with the rotating cross-bridge model for muscle contraction has been the inability to detect any large conformational changes within the myosin molecule to account for a working stroke of 5-10 nm. The recent crystal structure of myosin subfragment-1 suggests a solution to this problem by showing the presence of two distinct domains: a catalytic or motor domain, from which extends a long, 8.5-nm alpha-helix that is stabilized by the regulatory and essential light chains. Rayment et al. (1993) proposed that closure of a cleft in the motor domain could rotate the light chain-binding domain by a sufficient distance to account for the power stroke. With the development of new in vitro motility assays, and the ability to prepare unusual myosins by biochemical and molecular biological methods, we can now examine this hypothesis and explore the role of the light chains in generating force and movement. Here we will review some of these recent data and outline a possible mechanism for how light chains regulate contractile properties.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for PubMed Central
Loading ...
Support Center