3UCT

Structure of Mn2+-bound N-terminal domain of calmodulin in the presence of Zn2+


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.202 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

X-ray Structures of Magnesium and Manganese Complexes with the N-Terminal Domain of Calmodulin: Insights into the Mechanism and Specificity of Metal Ion Binding to an EF-Hand.

Senguen, F.T.Grabarek, Z.

(2012) Biochemistry 51: 6182-6194

  • DOI: 10.1021/bi300698h
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Calmodulin (CaM), a member of the EF-hand superfamily, regulates many aspects of cell function by responding specifically to micromolar concentrations of Ca(2+) in the presence of an ~1000-fold higher concentration of cellular Mg(2+). To explain the ...

    Calmodulin (CaM), a member of the EF-hand superfamily, regulates many aspects of cell function by responding specifically to micromolar concentrations of Ca(2+) in the presence of an ~1000-fold higher concentration of cellular Mg(2+). To explain the structural basis of metal ion binding specificity, we have determined the X-ray structures of the N-terminal domain of calmodulin (N-CaM) in complexes with Mg(2+), Mn(2+), and Zn(2+). In contrast to Ca(2+), which induces domain opening in CaM, octahedrally coordinated Mg(2+) and Mn(2+) stabilize the closed-domain, apo-like conformation, while tetrahedrally coordinated Zn(2+) ions bind at the protein surface and do not compete with Ca(2+). The relative positions of bound Mg(2+) and Mn(2+) within the EF-hand loops are similar to those of Ca(2+); however, the Glu side chain at position 12 of the loop, whose bidentate interaction with Ca(2+) is critical for domain opening, does not bind directly to either Mn(2+) or Mg(2+), and the vacant ligand position is occupied by a water molecule. We conclude that this critical interaction is prevented by specific stereochemical constraints imposed on the ligands by the EF-hand β-scaffold. The structures suggest that Mg(2+) contributes to the switching off of calmodulin activity and possibly other EF-hand proteins at the resting levels of Ca(2+). The Mg(2+)-bound N-CaM structure also provides a unique view of a transiently bound hydrated metal ion and suggests a role for the hydration water in the metal-induced conformational change.


    Organizational Affiliation

    Boston Biomedical Research Institute, Watertown, MA 02472, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Calmodulin
A, B
79Homo sapiensMutation(s): 0 
Gene Names: CALM3 (CALML2, CAM3, CAMC, CAMIII)
Find proteins for P0DP25 (Homo sapiens)
Go to Gene View: CALM3
Go to UniProtKB:  P0DP25
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

Download SDF File 
Download CCD File 
A, B
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
ZN
Query on ZN

Download SDF File 
Download CCD File 
A, B
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.202 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 36.288α = 90.00
b = 35.463β = 93.12
c = 58.343γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
DENZOdata reduction
SCALEPACKdata scaling
AutoSolphasing
SCALAdata scaling
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-08-08
    Type: Initial release
  • Version 1.1: 2012-10-03
    Type: Database references