3U10

Tetramerization dynamics of the C-terminus underlies isoform-specific cAMP-gating in HCN channels


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.200 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Tetramerization dynamics of C-terminal domain underlies isoform-specific cAMP gating in hyperpolarization-activated cyclic nucleotide-gated channels.

Lolicato, M.Nardini, M.Gazzarrini, S.Moller, S.Bertinetti, D.Herberg, F.W.Bolognesi, M.Martin, H.Fasolini, M.Bertrand, J.A.Arrigoni, C.Thiel, G.Moroni, A.

(2011) J.Biol.Chem. 286: 44811-44820

  • DOI: 10.1074/jbc.M111.297606
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are dually activated by hyperpolarization and binding of cAMP to their cyclic nucleotide binding domain (CNBD). HCN isoforms respond differently to cAMP; binding of cAMP shifts activa ...

    Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are dually activated by hyperpolarization and binding of cAMP to their cyclic nucleotide binding domain (CNBD). HCN isoforms respond differently to cAMP; binding of cAMP shifts activation of HCN2 and HCN4 by 17 mV but shifts that of HCN1 by only 2-4 mV. To explain the peculiarity of HCN1, we solved the crystal structures and performed a biochemical-biophysical characterization of the C-terminal domain (C-linker plus CNBD) of the three isoforms. Our main finding is that tetramerization of the C-terminal domain of HCN1 occurs at basal cAMP concentrations, whereas those of HCN2 and HCN4 require cAMP saturating levels. Therefore, HCN1 responds less markedly than HCN2 and HCN4 to cAMP increase because its CNBD is already partly tetrameric. This is confirmed by voltage clamp experiments showing that the right-shifted position of V(½) in HCN1 is correlated with its propensity to tetramerize in vitro. These data underscore that ligand-induced CNBD tetramerization removes tonic inhibition from the pore of HCN channels.


    Organizational Affiliation

    Department of Biology and Consiglio Nazionale delle Ricerche-Istituto di Biofisica, University of Milan, Via Celoria 26, 20133 Milan, Italy.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 2
A
210Homo sapiensMutation(s): 0 
Gene Names: HCN2 (BCNG2)
Find proteins for Q9UL51 (Homo sapiens)
Go to Gene View: HCN2
Go to UniProtKB:  Q9UL51
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CMP
Query on CMP

Download SDF File 
Download CCD File 
A
ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE
CYCLIC AMP; CAMP
C10 H12 N5 O6 P
IVOMOUWHDPKRLL-KQYNXXCUSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
CMPKd: 3600 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.272 
  • R-Value Work: 0.200 
  • Space Group: P 4 21 2
Unit Cell:
Length (Å)Angle (°)
a = 96.730α = 90.00
b = 96.730β = 90.00
c = 50.790γ = 90.00
Software Package:
Software NamePurpose
MAR345dtbdata collection
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-10-26
    Type: Initial release
  • Version 1.1: 2013-07-10
    Type: Database references