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Local and global interpretations of a disease-causing mutation near the ligand entry path in hyperpolarization-activated cAMP-gated channel
- Source :
- Structure (London, England : 1993). 20(12)
- Publication Year :
- 2012
-
Abstract
- SummaryHyperpolarization-activated, cAMP-gated (HCN) channels sense membrane potential and intracellular cAMP levels. A mutation identified in the cAMP binding domain (CNBD) of the human HCN4 channel, S672R, severely reduces the heart rate, but the molecular mechanism has been unclear. Our biochemical binding assays on isolated CNBD and patch-clamp recordings on the functional channel show that S672R reduces cAMP binding. The crystal structure of the mutant CNBD revealed no global changes except a disordered loop on the cAMP entry path. To address this localized structural perturbation at a whole protein level, we studied the activity-dependent dynamic interaction between cAMP and the functional channel using the patch-clamp fluorometry technique. S672R reduces the binding of cAMP to the channels in the resting state and significantly increases the unbinding rate during channel deactivation. This study on a disease-causing mutation illustrates the important roles played by the structural elements on the ligand entry-exit path in stabilizing the bound ligand in the binding pocket.
- Subjects :
- Models, Molecular
Patch-Clamp Techniques
Potassium Channels
Xenopus
Mutant
Amino Acid Motifs
Mutation, Missense
Cyclic Nucleotide-Gated Cation Channels
Muscle Proteins
Fluorescence Polarization
Crystallography, X-Ray
Article
Structural Biology
Cyclic AMP
Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels
Animals
Humans
Disease-causing Mutation
Molecular Biology
Membrane potential
Binding Sites
Resting state fMRI
Chemistry
Hyperpolarization (biology)
Protein Structure, Tertiary
Kinetics
Biochemistry
Biophysics
CAMP binding
Intracellular
Communication channel
Protein Binding
Subjects
Details
- ISSN :
- 18784186
- Volume :
- 20
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- Structure (London, England : 1993)
- Accession number :
- edsair.doi.dedup.....701eac5847aa943ec3eeddd11c22a976