1AHR

CALMODULIN MUTANT WITH A TWO RESIDUE DELETION IN THE CENTRAL HELIX


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Work: 0.211 
  • R-Value Observed: 0.211 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

The structure of a calmodulin mutant with a deletion in the central helix: implications for molecular recognition and protein binding.

Tabernero, L.Taylor, D.A.Chandross, R.J.VanBerkum, M.F.Means, A.R.Quiocho, F.A.Sack, J.S.

(1997) Structure 5: 613-622

  • DOI: https://doi.org/10.1016/s0969-2126(97)00217-7
  • Primary Citation of Related Structures:  
    1AHR

  • PubMed Abstract: 

    Calmodulin (CaM) is the major calcium-dependent regulator of a large variety of important intracellular processes in eukaryotes. The structure of CaM consists of two globular calcium-binding domains joined by a central 28-residue alpha helix. This linker helix has been hypothesized to act as a flexible tether and is crucial for the binding and activation of numerous target proteins. Although the way in which alterations of the central helix modulate the molecular recognition mechanism is not known exactly, the relative orientation of the globular domains seems to be of great importance. The structural analysis of central helix mutants may contribute to a better understanding of how changes in the conformation of CaM effect its function. We have determined the crystal structure of a calcium-saturated mutant of chicken CaM (mut-2) that lacks two residues in the central helix, Thr79 and Asp80, at 1.8 A resolution. The mutated shorter central helix is straight, relative to that of the wild-type structure. The loss of a partial turn of the central alpha helix causes the C-terminal domain to rotate 220 degrees around the helix axis, with respect to the N-terminal domain. This rotation places the two domains on the same side of the central helix, in a cis orientation, rather than in the trans orientation found in wild-type structures. The deletion of two residues in the central helix of CaM does not distort or cause a bending of the linker alpha helix. The main consequence of the mutation is a change in the relative orientation of the two globular calcium-binding domains, causing the hydrophobic patches in these domains to be closer and much less accessible to interact with the target enzymes. This may explain why this mutant of CaM shows a marked decrease in its ability to activate some enzymes while the mutation has little or no effect on its ability to activate others.


  • Organizational Affiliation

    Department of Macromolecular Crystallography Bristol-Myers Squibb Pharmaceutical Research Institute Princeton, NJ 08543-4000, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CALMODULIN146Gallus gallusMutation(s): 0 
UniProt
Find proteins for P62149 (Gallus gallus)
Explore P62149 
Go to UniProtKB:  P62149
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP62149
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Work: 0.211 
  • R-Value Observed: 0.211 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 27.09α = 90
b = 55.51β = 90
c = 100.89γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
UCSDdata reduction
ROCKSdata scaling
X-PLORphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-06-16
    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: 2022-12-21
    Changes: Database references, Derived calculations, Other
  • Version 1.4: 2023-08-09
    Changes: Refinement description
  • Version 1.5: 2024-05-22
    Changes: Data collection