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Title | The structure of the actin-smooth muscle myosin motor domain complex in the rigor state. |
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Journal, issue, pages | J Struct Biol, Vol. 200, Issue 3, Page 325-333, Year 2017 |
Publish date | Oct 14, 2017 |
Authors | Chaity Banerjee / Zhongjun Hu / Zhong Huang / J Anthony Warrington / Dianne W Taylor / Kathleen M Trybus / Susan Lowey / Kenneth A Taylor / |
PubMed Abstract | Myosin-based motility utilizes catalysis of ATP to drive the relative sliding of F-actin and myosin. The earliest detailed model based on cryo-electron microscopy (cryoEM) and X-ray crystallography ...Myosin-based motility utilizes catalysis of ATP to drive the relative sliding of F-actin and myosin. The earliest detailed model based on cryo-electron microscopy (cryoEM) and X-ray crystallography postulated that higher actin affinity and lever arm movement were coupled to closure of a feature of the myosin head dubbed the actin-binding cleft. Several studies since then using crystallography of myosin-V and cryoEM structures of F-actin bound myosin-I, -II and -V have provided details of this model. The smooth muscle myosin II interaction with F-actin may differ from those for striated and non-muscle myosin II due in part to different lengths of important surface loops. Here we report a ∼6 Å resolution reconstruction of F-actin decorated with the nucleotide-free recombinant smooth muscle myosin-II motor domain (MD) from images recorded using a direct electron detector. Resolution is highest for F-actin and the actin-myosin interface (3.5-4 Å) and lowest (∼6-7 Å) for those parts of the MD at the highest radius. Atomic models built into the F-actin density are quite comparable to those previously reported for rabbit muscle actin and show density from the bound ADP. The atomic model of the MD, is quite similar to a recently published structure of vertebrate non-muscle myosin II bound to F-actin and a crystal structure of nucleotide free myosin-V. Larger differences are observed when compared to the cryoEM structure of F-actin decorated with rabbit skeletal muscle myosin subfragment 1. The differences suggest less closure of the 50 kDa domain in the actin bound skeletal muscle myosin structure. |
External links | J Struct Biol / PubMed:29038012 / PubMed Central |
Methods | EM (helical sym.) |
Resolution | 6.0 Å |
Structure data | |
Chemicals | ChemComp-ADP: ChemComp-MG: |
Source |
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Keywords | MOTOR PROTEIN / ADP-F-actin / apo-myosin / helix muscle |