Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - A1B 

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

Macromolecule Content

• Total Structure Weight: 19.74 kDa 
• Atom Count: 1662 
• Residue Count: 164 
• Unique protein chains: 2

2F3Y

Calmodulin/IQ domain complex

• DOI: 10.2210/pdb2F3Y/pdb

• Classification: METAL BINDING PROTEIN
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2005-11-22 Released: 2005-12-27 
• Deposition Author(s): Fallon, J.L., Quiocho, F.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.45 Å
• R-Value Free: 0.219 
• R-Value Work: 0.189 
• R-Value Observed: 0.189 

Literature

Structure of Calmodulin Bound to the Hydrophobic IQ Domain of the Cardiac Ca(v)1.2 Calcium Channel.

Fallon, J.L., Halling, D.B., Hamilton, S.L., Quiocho, F.A.

(2005) Structure 13: 1881-1886

• PubMed: 16338416 
• DOI: 10.1016/j.str.2005.09.021
• Structures With Same Primary Citation


• PubMed Abstract: 
  

Ca2+-dependent inactivation (CDI) and facilitation (CDF) of the Ca(v)1.2 Ca2+ channel require calmodulin binding to a putative IQ motif in the carboxy-terminal tail of the pore-forming subunit. We present the 1.45 A crystal structure of Ca2+-calmodulin bound to a 21 residue peptide corresponding to the IQ domain of Ca(v)1.2. This structure shows that parallel binding of calmodulin to the IQ domain is governed by hydrophobic interactions. Mutations of residues I1672 and Q1673 in the peptide to alanines, which abolish CDI but not CDF in the channel, do not greatly alter the structure. Both lobes of Ca2+-saturated CaM bind to the IQ peptide but isoleucine 1672, thought to form an intramolecular interaction that drives CDI, is buried. These findings suggest that this structure could represent the conformation that calmodulin assumes in CDF.

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Related Citations: 

• Calmodulin interactions with IQ peptides from voltage-dependent calcium channels
  Black, D.J., Halling, D.B., Mandich, D.V., Pedersen, S.E., Altshuld, R.A., Hamilton, S.L.
  (2005) Am J Physiol Cell Physiol 288: C669

• Target enzyme recognition by calmodulin: 2.4 A structure of a calmodulin-peptide complex
  Meador, W.E., Means, A.R., Quiocho, F.A.
  (1992) Science 257: 1251

• A closed compact structure of native Ca(2+)-calmodulin
  Fallon, J.L., Quiocho, F.A.
  (2003) Structure 11: 1303

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Organizational Affiliation: 

Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.

Macromolecules

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details
Voltage-dependent L-type calcium channel alpha-1C subunit	B	21	N/A	Mutation(s): 0
Find proteins for Q13936 (Homo sapiens) Go to UniProtKB:  Q13936
NIH Common Fund Data Resources
PHAROS  Q13936 GTEx  ENSG00000151067

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Calmodulin	A	148	Homo sapiens	Mutation(s): 0  Gene Names: CALM1, calm2, calm3, CALM, CAM, CAM1
Find proteins for P0DP23 (Homo sapiens) Go to UniProtKB:  P0DP23
NIH Common Fund Data Resources
PHAROS  P0DP23 GTEx  ENSG00000198668

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	A	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N
MG	A	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.45 Å
• R-Value Free: 0.219 
• R-Value Work: 0.189 
• R-Value Observed: 0.189 
• Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 86.2	α = 90
b = 30.96	β = 114.54
c = 63.94	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
CNS	phasing
CNS	refinement
PDB_EXTRACT	data extraction
MAR345	data collection

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2005-11-22 
• Released Date: 2005-12-27 
Deposition Author(s): Fallon, J.L., Quiocho, F.A.

Revision History 

• Version 1.0: 2005-12-27
  Type: Initial release
  
• Version 1.1: 2008-05-01
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2017-10-18
  Changes: Refinement description