Biological Assembly 1  

 3D View: Structure | Electron Density | Validation Report | Ligand Interaction

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: 129.50 kDa 
• Atom Count: 8702 
• Modelled Residue Count: 1086 
• Deposited Residue Count: 1130 
• Unique protein chains: 3

1KK8

SCALLOP MYOSIN (S1-ADP-BeFx) IN THE ACTIN-DETACHED CONFORMATION

• DOI: 10.2210/pdb1KK8/pdb

• Classification: CONTRACTILE PROTEIN
• Organism(s): Argopecten irradians
• Mutation(s): No 


• Deposited: 2001-12-06 Released: 2002-10-09 
• Deposition Author(s): Himmel, M., Gourinath, S., Reshetnikova, L., Shen, Y., Szent-Gyorgyi, G., Cohen, C.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.269 
• R-Value Work: 0.230 
• R-Value Observed: 0.234 

Literature

Crystallographic findings on the internally uncoupled and near-rigor states of myosin: further insights into the mechanics of the motor.

Himmel, D.M., Gourinath, S., Reshetnikova, L., Shen, Y., Szent-Gyorgyi, A.G., Cohen, C.

(2002) Proc Natl Acad Sci U S A 99: 12645-12650

• PubMed: 12297624 
• DOI: 10.1073/pnas.202476799
• Primary Citation of Related Structures:  
  1KK7, 1KK8, 1KQM, 1KWO, 1L2O


• PubMed Abstract: 
  

Here we report a 2.3-A crystal structure of scallop myosin S1 complexed with ADP.BeF(x), as well as three additional structures (at 2.8-3.8 A resolution) for this S1 complexed with ATP analogs, some of which are cross-linked by para-phenyl dimaleimide, a short intramolecular cross-linker. In all cases, the complexes are characterized by an unwound SH1 helix first seen in an unusual 2.5-A scallop myosin-MgADP structure and described as corresponding to a previously unrecognized actin-detached internally uncoupled state. The unwinding of the SH1 helix effectively uncouples the converter/lever arm module from the motor and allows cross-linking by para-phenyl dimaleimide, which has been shown to occur only in weak actin-binding states of the molecule. Mutations near the metastable SH1 helix that disable the motor can be accounted for by viewing this structural element as a clutch controlling the transmission of torque to the lever arm. We have also determined a 3.2-A nucleotide-free structure of scallop myosin S1, which suggests that in the near-rigor state there are two conformations in the switch I loop, depending on whether nucleotide is present. Analysis of the subdomain motions in the weak actin-binding states revealed by x-ray crystallography, together with recent electron microscopic results, clarify the mechanical roles of the parts of the motor in the course of the contractile cycle and suggest how strong binding to actin triggers both the power stroke and product release.

---

Related Citations: 

• ATOMIC STRUCTURE OF SCALLOP MYOSIN SUBFRAGMENT S1 COMPLEXED WITH MGADP: A NOVEL CONFORMATION OF THE MYOSIN HEAD
  HOUDUSSE, A., KALABOKIS, V., HIMMEL, D., SZENT-GYORGYI, A.G., COHEN, C.
  (1999) Cell 97: 459

---

Organizational Affiliation: 

Rosenstiel Basic Medical Sciences Research Center, Waltham, MA 02454-9110, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Myosin Heavy Chain, Striated muscle	A	837	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, Striated adductor muscle	B	139	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,Striated adductor muscle	C	154	Argopecten irradians	Mutation(s): 0
UniProt
Find proteins for P07291 (Argopecten irradians) Explore P07291  Go to UniProtKB:  P07291

Small Molecules

Ligands 5 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
ADP (Subject of Investigation/LOI)	F [auth A]	ADENOSINE-5'-DIPHOSPHATE C10 H15 N5 O10 P2 XTWYTFMLZFPYCI-KQYNXXCUSA-N
GOL	G [auth A]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
BEF	E [auth A]	BERYLLIUM TRIFLUORIDE ION Be F3 OGIAHMCCNXDTIE-UHFFFAOYSA-K
CA	I [auth C]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N
MG	D [auth A], H [auth B]	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.269 
• R-Value Work: 0.230 
• R-Value Observed: 0.234 
• Space Group: P 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 51.604	α = 81.08
b = 58.527	β = 84.94
c = 133.295	γ = 67.24

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing
CNS	refinement

Structure Validation

Ligand Structure Quality Assessment  

Entry History 

Deposition Data

• Deposited Date: 2001-12-06 
• Released Date: 2002-10-09 
Deposition Author(s): Himmel, M., Gourinath, S., Reshetnikova, L., Shen, Y., Szent-Gyorgyi, G., Cohen, C.

Revision History  

• Version 1.0: 2002-10-09
  Type: Initial release
  
• Version 1.1: 2008-04-27
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Non-polymer description, Version format compliance
• Version 1.3: 2016-06-01
  Changes: Source and taxonomy