3DTP

Tarantula heavy meromyosin obtained by flexible docking to Tarantula muscle thick filament Cryo-EM 3D-MAP


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 20 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Three-Dimensional Reconstruction of Tarantula Myosin Filaments Suggests How Phosphorylation May Regulate Myosin Activity

Alamo, L.Wriggers, W.Pinto, A.Bartoli, F.Salazar, L.Zhao, F.Q.Craig, R.Padron, R.

(2008) J.Mol.Biol. 384: 780-797

  • DOI: 10.1016/j.jmb.2008.10.013
  • Also Cited By: 5TBY, 3JBH, 3JAX

  • PubMed Abstract: 
  • Muscle contraction involves the interaction of the myosin heads of the thick filaments with actin subunits of the thin filaments. Relaxation occurs when this interaction is blocked by molecular switches on these filaments. In many muscles, myosin-lin ...

    Muscle contraction involves the interaction of the myosin heads of the thick filaments with actin subunits of the thin filaments. Relaxation occurs when this interaction is blocked by molecular switches on these filaments. In many muscles, myosin-linked regulation involves phosphorylation of the myosin regulatory light chains (RLCs). Electron microscopy of vertebrate smooth muscle myosin molecules (regulated by phosphorylation) has provided insight into the relaxed structure, revealing that myosin is switched off by intramolecular interactions between its two heads, the free head and the blocked head. Three-dimensional reconstruction of frozen-hydrated specimens revealed that this asymmetric head interaction is also present in native thick filaments of tarantula striated muscle. Our goal in this study was to elucidate the structural features of the tarantula filament involved in phosphorylation-based regulation. A new reconstruction revealed intra- and intermolecular myosin interactions in addition to those seen previously. To help interpret the interactions, we sequenced the tarantula RLC and fitted an atomic model of the myosin head that included the predicted RLC atomic structure and an S2 (subfragment 2) crystal structure to the reconstruction. The fitting suggests one intramolecular interaction, between the cardiomyopathy loop of the free head and its own S2, and two intermolecular interactions, between the cardiac loop of the free head and the essential light chain of the blocked head and between the Leu305-Gln327 interaction loop of the free head and the N-terminal fragment of the RLC of the blocked head. These interactions, added to those previously described, would help switch off the thick filament. Molecular dynamics simulations suggest how phosphorylation could increase the helical content of the RLC N-terminus, weakening these interactions, thus releasing both heads and activating the thick filament.


    Related Citations: 
    • Crystal structures of human cardiac beta-myosin II S2-Delta provide insight into the functional role of the S2 subfragment
      Blankenfeldt, W.,Thoma, N.H.,Wray, J.S.,Gautel, M.,Schlichting, I.
      (2006) Proc.Natl.Acad.Sci.Usa 103: 17713
    • Refined model of the 10S conformation of smooth muscle myosin by cryo-electron microscopy 3D image reconstruction
      Liu, J.,Wendt, T.,Taylor, D.,Taylor, K.
      (2003) J.Mol.Biol. 329: 963
    • Atomic structure of scallop myosin subfragment S1 complexed with MgADP: a novel conformation of the myosin head
      Houdusse, A.,Kalabokis, V.N.,Himmel, D.,Szent-Gyorgyi, A.G.,Cohen, C.
      (1999) Cell 97: 459


    Organizational Affiliation

    Departamento de BiologĂ­a Estructural, Instituto Venezolano de Investigaciones CientĂ­ficas, Caracas, Venezuela.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Myosin 2 heavy chain chimera of smooth and cardiac muscle
A
971Gallus gallusHomo sapiens
This entity is chimeric
Gene Names: MYH11, MYH7 (MYHCB)
Find proteins for P10587 (Gallus gallus)
Go to Gene View: MYH11
Go to UniProtKB:  P10587
Find proteins for P12883 (Homo sapiens)
Go to Gene View: MYH7
Go to UniProtKB:  P12883
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Myosin 2 heavy chain chimera of smooth and cardiac muscle
B
973Gallus gallusHomo sapiens
This entity is chimeric
Gene Names: MYH11, MYH7 (MYHCB)
Find proteins for P10587 (Gallus gallus)
Go to Gene View: MYH11
Go to UniProtKB:  P10587
Find proteins for P12883 (Homo sapiens)
Go to Gene View: MYH7
Go to UniProtKB:  P12883
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Smooth muscle myosin essential light chain
C, D
150Gallus gallusGene Names: MYL6
Find proteins for P02607 (Gallus gallus)
Go to Gene View: MYL6
Go to UniProtKB:  P02607
Entity ID: 4
MoleculeChainsSequence LengthOrganismDetails
Myosin regulatory light chain
E, F
196Avicularia aviculariaGene Names: RLC
Find proteins for B4XT43 (Avicularia avicularia)
Go to UniProtKB:  B4XT43
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 20 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-10-07
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2015-07-22
    Type: Source and taxonomy
  • Version 1.3: 2016-12-14
    Type: Other