6BIH

The Structure of the Actin-Smooth Muscle Myosin Motor Domain Complex in the Rigor State

Summary for 6BIH

• Entry DOI: 10.2210/pdb6bih/pdb
• EMDB information: 7100
• Descriptor: Myosin-11, Actin, alpha skeletal muscle, ADENOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: adp-f-actin, apo-myosin, helix muscle, motor protein
• Biological source: Gallus gallus (Chicken); More
• Total number of polymer chains: 2
• Total formula weight: 133891.69

Authors

Taylor, K.A.,Banerjee, C.,Hu, Z. (deposition date: 2017-11-02, release date: 2018-09-19, Last modification date: 2024-03-13)

Primary citation

Banerjee, C.,Hu, Z.,Huang, Z.,Warrington, J.A.,Taylor, D.W.,Trybus, K.M.,Lowey, S.,Taylor, K.A.
The structure of the actin-smooth muscle myosin motor domain complex in the rigor state.
J. Struct. Biol., 200:325-333, 2017

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 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.

PubMed: 29038012
DOI: 10.1016/j.jsb.2017.10.003

Experimental method

ELECTRON MICROSCOPY (6 Å)