Biological Assembly 1  

 3D View: Structure

Global Symmetry: Cyclic - C4  (3D View)
Global Stoichiometry: Hetero 216-mer - A72B72C72 Pseudo Symmetry: Cyclic - C4  (3D View)
Pseudo Stoichiometry: Hetero 216-mer - A72B36C36D36E36 

Biological assembly 1 assigned by authors and generated by (software)

Macromolecule Content

• Total Structure Weight: 301.07 kDa 
• Atom Count: 20580 
• Modelled Residue Count: 2566 
• Deposited Residue Count: 2636 
• Unique protein chains: 4

3DTP

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

• DOI: 10.2210/pdb3DTP/pdb
• EMDataResource: EMD-1950

• Classification: CONTRACTILE PROTEIN
• Organism(s): Gallus gallus, Homo sapiens, Avicularia avicularia
• Expression System: Spodoptera frugiperda
• Mutation(s): No 


• Deposited: 2008-07-15 Released: 2008-10-07 
• Deposition Author(s): Alamo, L., Wriggers, W., Pinto, A., Bartoli, F., Salazar, L., Zhao, F.Q., Craig, R., Padron, R.

---

Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 20.0 Å
• Aggregation State: FILAMENT 
• Reconstruction Method: HELICAL 

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

• PubMed: 18951904 
• DOI: 10.1016/j.jmb.2008.10.013
• Primary Citation of Related Structures:  
  3DTP


• 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-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: 

• 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

• 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 U S A 103: 17713

• 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 Biología Estructural, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Myosin-11,Myosin-7	A	971	Gallus gallus, Homo sapiens This entity is chimeric	Mutation(s): 0  Gene Names: MYH11, MYH7, MYHCB
Find proteins for P10587 (Gallus gallus) Explore P10587  Go to UniProtKB:  P10587
Find proteins for P12883 (Homo sapiens) Explore P12883  Go to UniProtKB:  P12883
NIH Common Fund Data Resources
PHAROS:  P12883 GTEx:  ENSG00000092054

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
Myosin-11,Myosin-7	B	973	Gallus gallus, Homo sapiens This entity is chimeric	Mutation(s): 0  Gene Names: MYH11, MYH7, MYHCB
Find proteins for P10587 (Gallus gallus) Explore P10587  Go to UniProtKB:  P10587
Find proteins for P12883 (Homo sapiens) Explore P12883  Go to UniProtKB:  P12883
NIH Common Fund Data Resources
PHAROS:  P12883 GTEx:  ENSG00000092054

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
Myosin light polypeptide 6	C, D	150	Gallus gallus	Mutation(s): 0  Gene Names: MYL6
Find proteins for P02607 (Gallus gallus) Explore P02607  Go to UniProtKB:  P02607

Entity ID: 4
Molecule	Chains	Sequence Length	Organism	Details	Image
Myosin II regulatory light chain	E, F	196	Avicularia avicularia	Mutation(s): 0  Gene Names: RLC
Find proteins for B4XT43 (Avicularia avicularia) Explore B4XT43  Go to UniProtKB:  B4XT43

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 20.0 Å
• Aggregation State: FILAMENT 
• Reconstruction Method: HELICAL 

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2008-07-15 
• Released Date: 2008-10-07 
Deposition Author(s): Alamo, L., Wriggers, W., Pinto, A., Bartoli, F., Salazar, L., Zhao, F.Q., Craig, R., Padron, R.

Revision History  

• Version 1.0: 2008-10-07
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2015-07-22
  Changes: Source and taxonomy
• Version 1.3: 2016-12-14
  Changes: Other
• Version 1.4: 2020-01-29
  Changes: Author supporting evidence, Data collection, Database references, Source and taxonomy, Structure summary