Lethocerus Myosin II complete coiled-coil domain resolved in its native environment

Experimental Data Snapshot

  • Resolution: 4.25 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 

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The myosin II coiled-coil domain atomic structure in its native environment.

Rahmani, H.Ma, W.Hu, Z.Daneshparvar, N.Taylor, D.W.McCammon, J.A.Irving, T.C.Edwards, R.J.Taylor, K.A.

(2021) Proc Natl Acad Sci U S A 118

  • DOI: https://doi.org/10.1073/pnas.2024151118
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The atomic structure of the complete myosin tail within thick filaments isolated from Lethocerus indicus flight muscle is described and compared to crystal structures of recombinant, human cardiac myosin tail segments. Overall, the agreement is good with three exceptions: the proximal S2, in which the filament has heads attached but the crystal structure doesn't, and skip regions 2 and 4. At the head-tail junction, the tail α-helices are asymmetrically structured encompassing well-defined unfolding of 12 residues for one myosin tail, ∼4 residues of the other, and different degrees of α-helix unwinding for both tail α-helices, thereby providing an atomic resolution description of coiled-coil "uncoiling" at the head-tail junction. Asymmetry is observed in the nonhelical C termini; one C-terminal segment is intercalated between ribbons of myosin tails, the other apparently terminating at Skip 4 of another myosin tail. Between skip residues, crystal and filament structures agree well. Skips 1 and 3 also agree well and show the expected α-helix unwinding and coiled-coil untwisting in response to skip residue insertion. Skips 2 and 4 are different. Skip 2 is accommodated in an unusual manner through an increase in α-helix radius and corresponding reduction in rise/residue. Skip 4 remains helical in one chain, with the other chain unfolded, apparently influenced by the acidic myosin C terminus. The atomic model may shed some light on thick filament mechanosensing and is a step in understanding the complex roles that thick filaments of all species undergo during muscle contraction.

  • Organizational Affiliation

    Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Myosin heavy chain isoform Mhc_X1A [auth B],
B [auth A]
1,971Lethocerus indicusMutation(s): 0 
Find proteins for A0A221IRH5 (Lethocerus indicus)
Explore A0A221IRH5 
Go to UniProtKB:  A0A221IRH5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A221IRH5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 4.25 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR01 GM30598
American Heart AssociationUnited States20PRE35120273

Revision History  (Full details and data files)

  • Version 1.0: 2021-03-24
    Type: Initial release
  • Version 1.1: 2021-03-31
    Changes: Database references
  • Version 1.2: 2021-04-14
    Changes: Database references