Crystal structure of a vertebrate smooth muscle myosin motor domain and its complex with the essential light chain: visualization of the pre-power stroke state.
Dominguez, R., Freyzon, Y., Trybus, K.M., Cohen, C.(1998) Cell 94: 559-571
- PubMed: 9741621 
- DOI: https://doi.org/10.1016/s0092-8674(00)81598-6
- Primary Citation of Related Structures:  
1BR1, 1BR2, 1BR4 - PubMed Abstract: 
The crystal structures of an expressed vertebrate smooth muscle myosin motor domain (MD) and a motor domain-essential light chain (ELC) complex (MDE), both with a transition state analog (MgADP x AIF4-) in the active site, have been determined to 2.9 A and 3.5 A resolution, respectively. The MDE structure with an ATP analog (MgADP x BeFx) was also determined to 3.6 A resolution. In all three structures, a domain of the C-terminal region, the "converter," is rotated approximately 70 degrees from that in nucleotide-free skeletal subfragment 1 (S1). We have found that the MDE-BeFx and MDE-AIF4- structures are almost identical, consistent with the fact that they both bind weakly to actin. A comparison of the lever arm positions in MDE-AIF4- and in nucleotide-free skeletal S1 shows that a potential displacement of approximately 10 nm can be achieved during the power stroke.
Organizational Affiliation: 
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454-9110, USA.