3OTF

Structural basis for the cAMP-dependent gating in human HCN4 channel


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.237 
  • R-Value Observed: 0.239 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Structural basis for the cAMP-dependent gating in the human HCN4 channel.

Xu, X.Vysotskaya, Z.V.Liu, Q.Zhou, L.

(2010) J Biol Chem 285: 37082-37091

  • DOI: https://doi.org/10.1074/jbc.M110.152033
  • Primary Citation of Related Structures:  
    3OTF

  • PubMed Abstract: 

    Hyperpolarization-activated cAMP-regulated (HCN) channels play important physiological roles in both cardiovascular and central nervous systems. Among the four HCN isoforms, HCN2 and HCN4 show high expression levels in the human heart, with HCN4 being the major cardiac isoform. The previously published crystal structure of the mouse HCN2 (mHCN2) C-terminal fragment, including the C-linker and the cyclic-nucleotide binding domain (CNBD), has provided many insights into cAMP-dependent gating in HCN channels. However, structures of other mammalian HCN channel isoforms have been lacking. Here we used a combination of approaches including structural biology, biochemistry, and electrophysiology to study cAMP-dependent gating in HCN4 channel. First we solved the crystal structure of the C-terminal fragment of human HCN4 (hHCN4) channel at 2.4 Å. Overall we observed a high similarity between mHCN2 and hHCN4 crystal structures. Functional comparison between two isoforms revealed that compared with mHCN2, the hHCN4 protein exhibited marked different contributions to channel function, such as a ∼3-fold reduction in the response to cAMP. Guided by structural differences in the loop region between β4 and β5 strands, we identified residues that could partially account for the differences in response to cAMP between mHCN2 and hHCN4 proteins. Moreover, upon cAMP binding, the hHCN4 C-terminal protein exerts a much prolonged effect in channel deactivation that could have significant physiological contributions.


  • Organizational Affiliation

    Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Potassium/sodium hyperpolarization-activated cyclic nucleotide-gated channel 4220Homo sapiensMutation(s): 0 
Gene Names: HCN4
UniProt & NIH Common Fund Data Resources
Find proteins for Q9Y3Q4 (Homo sapiens)
Explore Q9Y3Q4 
Go to UniProtKB:  Q9Y3Q4
PHAROS:  Q9Y3Q4
GTEx:  ENSG00000138622 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9Y3Q4
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
CMP
Query on CMP

Download Ideal Coordinates CCD File 
B [auth A]ADENOSINE-3',5'-CYCLIC-MONOPHOSPHATE
C10 H12 N5 O6 P
IVOMOUWHDPKRLL-KQYNXXCUSA-N
Binding Affinity Annotations 
IDSourceBinding Affinity
CMP PDBBind:  3OTF Kd: 830 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.237 
  • R-Value Observed: 0.239 
  • Space Group: I 4 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 69.264α = 90
b = 69.264β = 90
c = 191.616γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PHASERphasing
CNSrefinement
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-10-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2019-07-17
    Changes: Data collection, Refinement description
  • Version 1.3: 2023-09-06
    Changes: Data collection, Database references, Derived calculations, Refinement description