5JLF

Structure of the F-actin-tropomyosin complex (Reprocessed)

Summary for 5JLF

• Entry DOI: 10.2210/pdb5jlf/pdb
• EMDB information: 8162 8163
• Descriptor: Actin, alpha skeletal muscle, Tropomyosin Alpha-1, ADENOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: contractile filament, muscle, thin filament, cytoskeleton, structural protein, hydrolase complex, f-actin, tropomyosin, filament, protein polymers, cryo em, contractile protein
• Biological source: Mus musculus (House Mouse); More
• Total number of polymer chains: 7
• Total formula weight: 234650.05

Authors

von der Ecken, J.,Raunser, S. (deposition date: 2016-04-27, release date: 2016-06-15, Last modification date: 2025-04-09)

Primary citation

Ecken, J.V.,Heissler, S.M.,Pathan-Chhatbar, S.,Manstein, D.J.,Raunser, S.
Cryo-EM structure of a human cytoplasmic actomyosin complex at near-atomic resolution.
Nature, 534:724-728, 2016

PubMed Abstract: The interaction of myosin with actin filaments is the central feature of muscle contraction and cargo movement along actin filaments of the cytoskeleton. The energy for these movements is generated during a complex mechanochemical reaction cycle. Crystal structures of myosin in different states have provided important structural insights into the myosin motor cycle when myosin is detached from F-actin. The difficulty of obtaining diffracting crystals, however, has prevented structure determination by crystallography of actomyosin complexes. Thus, although structural models exist of F-actin in complex with various myosins, a high-resolution structure of the F-actin–myosin complex is missing. Here, using electron cryomicroscopy, we present the structure of a human rigor actomyosin complex at an average resolution of 3.9 Å. The structure reveals details of the actomyosin interface, which is mainly stabilized by hydrophobic interactions. The negatively charged amino (N) terminus of actin interacts with a conserved basic motif in loop 2 of myosin, promoting cleft closure in myosin. Surprisingly, the overall structure of myosin is similar to rigor-like myosin structures in the absence of F-actin, indicating that F-actin binding induces only minimal conformational changes in myosin. A comparison with pre-powerstroke and intermediate (Pi-release) states of myosin allows us to discuss the general mechanism of myosin binding to F-actin. Our results serve as a strong foundation for the molecular understanding of cytoskeletal diseases, such as autosomal dominant hearing loss and diseases affecting skeletal and cardiac muscles, in particular nemaline myopathy and hypertrophic cardiomyopathy.

PubMed: 27324845
DOI: 10.1038/nature18295

Experimental method

ELECTRON MICROSCOPY (3.6 Å)