1SCM

STRUCTURE OF THE REGULATORY DOMAIN OF SCALLOP MYOSIN AT 2.8 ANGSTROMS RESOLUTION

• PDB DOI: https://doi.org/10.2210/pdb1SCM/pdb

• Classification: CALCIUM-BINDING PROTEIN
• Organism(s): Argopecten irradians
• Mutation(s): No 


• Deposited: 1994-01-06 Released: 1994-04-30 
• Deposition Author(s): Cohen, C., Xie, X.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Work: 
  0.201 (Depositor) 
• R-Value Observed: 
  0.201 (Depositor) 

Literature

Structure of the regulatory domain of scallop myosin at 2.8 A resolution.

Xie, X., Harrison, D.H., Schlichting, I., Sweet, R.M., Kalabokis, V.N., Szent-Gyorgyi, A.G., Cohen, C.

(1994) Nature 368: 306-312

• PubMed: 8127365 
• DOI: https://doi.org/10.1038/368306a0
• Primary Citation of Related Structures:  
  1SCM


• PubMed Abstract: 
  

  The regulatory domain of scallop myosin is a three-chain protein complex that switches on this motor in response to Ca2+ binding. This domain has been crystallized and the structure solved to 2.8 A resolution. Side-chain interactions link the two light chains in tandem to adjacent segments of the heavy chain bearing the IQ-sequence motif. The Ca(2+)-binding site is a novel EF-hand motif on the essential light chain and is stabilized by linkages involving the heavy chain and both light chains, accounting for the requirement of all three chains for Ca2+ binding and regulation in the intact myosin molecule.

---

Organizational Affiliation: 

Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254-9110.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 3-mer - A1B1C1 

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

Macromolecule Content

• Total Structure Weight: 40.87 kDa 
• Atom Count: 2,816 
• Modelled Residue Count: 347 
• Deposited Residue Count: 354 
• Unique protein chains: 3

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
MYOSIN HEAVY CHAIN	A	60	Argopecten irradians	Mutation(s): 0
UniProt
Find proteins for P24733 (Argopecten irradians) Explore P24733  Go to UniProtKB:  P24733

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
MYOSIN REGULATORY LIGHT CHAIN	B	145	Argopecten irradians	Mutation(s): 0
UniProt
Find proteins for P13543 (Argopecten irradians) Explore P13543  Go to UniProtKB:  P13543

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
MYOSIN ESSENTIAL LIGHT CHAIN	C	149	Argopecten irradians	Mutation(s): 0
UniProt
Find proteins for P07291 (Argopecten irradians) Explore P07291  Go to UniProtKB:  P07291

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	D [auth B], E [auth C]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.80 Å
• R-Value Work:  0.201 (Depositor) 
• R-Value Observed: 0.201 (Depositor) 

Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 52.5	α = 90
b = 87	β = 114.5
c = 55.5	γ = 90

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	refinement
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 1994-04-30 
Deposition Author(s): Cohen, C., Xie, X.

Revision History  

• Version 1.0: 1994-04-30
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2018-04-04
  Changes: Data collection, Other
• Version 1.4: 2024-02-14
  Changes: Data collection, Database references, Derived calculations