Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis.
Once translocated into the cytosol of target cells, the catalytic domain (AC) of the adenylate cyclase toxin (CyaA), a major virulence factor of Bordetella pertussis, is potently activated by binding calmodulin (CaM) to produce supraphysiological levels of cAMP, inducing cell death. Using a combinat...
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doaj-2ad1a9bcfbe04cf3901288921d36c03e2021-07-02T17:20:00ZengPublic Library of Science (PLoS)PLoS Biology1544-91731545-78852017-12-011512e200448610.1371/journal.pbio.2004486Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis.Darragh P O'BrienDominique DurandAlexis VoegeleVéronique HourdelMarilyne DaviJulia Chamot-RookePatrice VachetteSébastien BrierDaniel LadantAlexandre ChenalOnce translocated into the cytosol of target cells, the catalytic domain (AC) of the adenylate cyclase toxin (CyaA), a major virulence factor of Bordetella pertussis, is potently activated by binding calmodulin (CaM) to produce supraphysiological levels of cAMP, inducing cell death. Using a combination of small-angle X-ray scattering (SAXS), hydrogen/deuterium exchange mass spectrometry (HDX-MS), and synchrotron radiation circular dichroism (SR-CD), we show that, in the absence of CaM, AC exhibits significant structural disorder, and a 75-residue-long stretch within AC undergoes a disorder-to-order transition upon CaM binding. Beyond this local folding, CaM binding induces long-range allosteric effects that stabilize the distant catalytic site, whilst preserving catalytic loop flexibility. We propose that the high enzymatic activity of AC is due to a tight balance between the CaM-induced decrease of structural flexibility around the catalytic site and the preservation of catalytic loop flexibility, allowing for fast substrate binding and product release. The CaM-induced dampening of AC conformational disorder is likely relevant to other CaM-activated enzymes.https://doi.org/10.1371/journal.pbio.2004486 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Darragh P O'Brien Dominique Durand Alexis Voegele Véronique Hourdel Marilyne Davi Julia Chamot-Rooke Patrice Vachette Sébastien Brier Daniel Ladant Alexandre Chenal |
spellingShingle |
Darragh P O'Brien Dominique Durand Alexis Voegele Véronique Hourdel Marilyne Davi Julia Chamot-Rooke Patrice Vachette Sébastien Brier Daniel Ladant Alexandre Chenal Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. PLoS Biology |
author_facet |
Darragh P O'Brien Dominique Durand Alexis Voegele Véronique Hourdel Marilyne Davi Julia Chamot-Rooke Patrice Vachette Sébastien Brier Daniel Ladant Alexandre Chenal |
author_sort |
Darragh P O'Brien |
title |
Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. |
title_short |
Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. |
title_full |
Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. |
title_fullStr |
Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. |
title_full_unstemmed |
Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. |
title_sort |
calmodulin fishing with a structurally disordered bait triggers cyaa catalysis. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS Biology |
issn |
1544-9173 1545-7885 |
publishDate |
2017-12-01 |
description |
Once translocated into the cytosol of target cells, the catalytic domain (AC) of the adenylate cyclase toxin (CyaA), a major virulence factor of Bordetella pertussis, is potently activated by binding calmodulin (CaM) to produce supraphysiological levels of cAMP, inducing cell death. Using a combination of small-angle X-ray scattering (SAXS), hydrogen/deuterium exchange mass spectrometry (HDX-MS), and synchrotron radiation circular dichroism (SR-CD), we show that, in the absence of CaM, AC exhibits significant structural disorder, and a 75-residue-long stretch within AC undergoes a disorder-to-order transition upon CaM binding. Beyond this local folding, CaM binding induces long-range allosteric effects that stabilize the distant catalytic site, whilst preserving catalytic loop flexibility. We propose that the high enzymatic activity of AC is due to a tight balance between the CaM-induced decrease of structural flexibility around the catalytic site and the preservation of catalytic loop flexibility, allowing for fast substrate binding and product release. The CaM-induced dampening of AC conformational disorder is likely relevant to other CaM-activated enzymes. |
url |
https://doi.org/10.1371/journal.pbio.2004486 |
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