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Structure and dynamics underlying elementary ligand binding events in human pacemaking channels
Although molecular recognition is crucial for cellular signaling, mechanistic studies have relied primarily on ensemble measures that average over and thereby obscure underlying steps. Single-molecule observations that resolve these steps are lacking due to diffraction-limited resolution of single f...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
eLife Sciences Publications, Ltd
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5115869/ https://www.ncbi.nlm.nih.gov/pubmed/27858593 http://dx.doi.org/10.7554/eLife.20797 |
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author | Goldschen-Ohm, Marcel P Klenchin, Vadim A White, David S Cowgill, John B Cui, Qiang Goldsmith, Randall H Chanda, Baron |
author_facet | Goldschen-Ohm, Marcel P Klenchin, Vadim A White, David S Cowgill, John B Cui, Qiang Goldsmith, Randall H Chanda, Baron |
author_sort | Goldschen-Ohm, Marcel P |
collection | PubMed |
description | Although molecular recognition is crucial for cellular signaling, mechanistic studies have relied primarily on ensemble measures that average over and thereby obscure underlying steps. Single-molecule observations that resolve these steps are lacking due to diffraction-limited resolution of single fluorophores at relevant concentrations. Here, we combined zero-mode waveguides with fluorescence resonance energy transfer (FRET) to directly observe binding at individual cyclic nucleotide-binding domains (CNBDs) from human pacemaker ion channels critical for heart and brain function. Our observations resolve the dynamics of multiple distinct steps underlying cyclic nucleotide regulation: a slow initial binding step that must select a 'receptive' conformation followed by a ligand-induced isomerization of the CNBD. X-ray structure of the apo CNBD and atomistic simulations reveal that the isomerization involves both local and global transitions. Our approach reveals fundamental mechanisms underpinning ligand regulation of pacemaker channels, and is generally applicable to weak-binding interactions governing a broad spectrum of signaling processes. DOI: http://dx.doi.org/10.7554/eLife.20797.001 |
format | Online Article Text |
id | pubmed-5115869 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | eLife Sciences Publications, Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-51158692016-11-28 Structure and dynamics underlying elementary ligand binding events in human pacemaking channels Goldschen-Ohm, Marcel P Klenchin, Vadim A White, David S Cowgill, John B Cui, Qiang Goldsmith, Randall H Chanda, Baron eLife Biophysics and Structural Biology Although molecular recognition is crucial for cellular signaling, mechanistic studies have relied primarily on ensemble measures that average over and thereby obscure underlying steps. Single-molecule observations that resolve these steps are lacking due to diffraction-limited resolution of single fluorophores at relevant concentrations. Here, we combined zero-mode waveguides with fluorescence resonance energy transfer (FRET) to directly observe binding at individual cyclic nucleotide-binding domains (CNBDs) from human pacemaker ion channels critical for heart and brain function. Our observations resolve the dynamics of multiple distinct steps underlying cyclic nucleotide regulation: a slow initial binding step that must select a 'receptive' conformation followed by a ligand-induced isomerization of the CNBD. X-ray structure of the apo CNBD and atomistic simulations reveal that the isomerization involves both local and global transitions. Our approach reveals fundamental mechanisms underpinning ligand regulation of pacemaker channels, and is generally applicable to weak-binding interactions governing a broad spectrum of signaling processes. DOI: http://dx.doi.org/10.7554/eLife.20797.001 eLife Sciences Publications, Ltd 2016-11-18 /pmc/articles/PMC5115869/ /pubmed/27858593 http://dx.doi.org/10.7554/eLife.20797 Text en © 2016, Goldschen-Ohm et al http://creativecommons.org/licenses/by/4.0/ This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited. |
spellingShingle | Biophysics and Structural Biology Goldschen-Ohm, Marcel P Klenchin, Vadim A White, David S Cowgill, John B Cui, Qiang Goldsmith, Randall H Chanda, Baron Structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
title | Structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
title_full | Structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
title_fullStr | Structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
title_full_unstemmed | Structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
title_short | Structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
title_sort | structure and dynamics underlying elementary ligand binding events in human pacemaking channels |
topic | Biophysics and Structural Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5115869/ https://www.ncbi.nlm.nih.gov/pubmed/27858593 http://dx.doi.org/10.7554/eLife.20797 |
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