3HFC

A trimeric form of the Kv7.1 A domain Tail, L602M/L606M mutant Semet


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.45 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.221 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure of a trimeric form of the K(V)7.1 (KCNQ1) A-domain tail coiled-coil reveals structural plasticity and context dependent changes in a putative coiled-coil trimerization motif.

Xu, Q.Minor, D.L.

(2009) Protein Sci. 18: 2100-2114

  • DOI: 10.1002/pro.224
  • Primary Citation of Related Structures:  3HFE

  • PubMed Abstract: 
  • Coiled-coils are widespread protein-protein interaction motifs typified by the heptad repeat (abcdefg)(n) in which "a" and "d" positions are hydrophobic residues. Although identification of likely coiled-coil sequences is robust, prediction of strand ...

    Coiled-coils are widespread protein-protein interaction motifs typified by the heptad repeat (abcdefg)(n) in which "a" and "d" positions are hydrophobic residues. Although identification of likely coiled-coil sequences is robust, prediction of strand order remains elusive. We present the X-ray crystal structure of a short form (residues 583-611), "Q1-short," of the coiled-coil assembly specificity domain from the voltage-gated potassium channel Kv7.1 (KCNQ1) determined at 1.7 A resolution. Q1-short lacks one and half heptads present in a previously studied tetrameric coiled-coil construct, Kv7.1 585-621, "Q1-long." Surprisingly, Q1-short crystallizes as a trimer. In solution, Q1-short self-assembles more poorly than Q1-long and depends on an R-h-x-x-h-E motif common to trimeric coiled-coils. Addition of native sequences that include "a" and "d" positions C-terminal to Q1-short overrides the R-h-x-x-h-E motif influence and changes assembly state from a weakly associated trimer to a strongly associated tetramer. These data provide a striking example of a naturally occurring amino sequence that exhibits context-dependent folding into different oligomerization states, a three-stranded versus a four-stranded coiled-coil. The results emphasize the degenerate nature of coiled-coil energy landscapes in which small changes can have drastic effects on oligomerization. Discovery of these properties in an ion channel assembly domain and prevalence of the R-h-x-x-h-E motif in coiled-coil assembly domains of a number of different channels that are thought to function as tetrameric assemblies raises the possibility that such sequence features may be important for facilitating the assembly of intermediates en route to the final native state.


    Organizational Affiliation

    Cardiovascular Research Institute, University of California, San Francisco, 94158-2330, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Potassium voltage-gated channel subfamily KQT member 1
A, B, C
31Homo sapiensGene Names: KCNQ1 (KCNA8, KCNA9, KVLQT1)
Find proteins for P51787 (Homo sapiens)
Go to Gene View: KCNQ1
Go to UniProtKB:  P51787
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B, C
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.45 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.221 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 60.431α = 90.00
b = 41.232β = 119.26
c = 34.723γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
ADSCdata collection
HKL-2000data reduction
REFMACrefinement
HKL-2000data scaling
SOLVEphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2009-05-11 
  • Released Date: 2009-09-01 
  • Deposition Author(s): Xu, Q., Minor, D.L.

Revision History 

  • Version 1.0: 2009-09-01
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance