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-Structure paper
Title | Calmodulin fishing with a structurally disordered bait triggers CyaA catalysis. |
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Journal, issue, pages | PLoS Biol, Vol. 15, Issue 12, Page e2004486, Year 2017 |
Publish date | Dec 29, 2017 |
Authors | Darragh P O'Brien / Dominique Durand / Alexis Voegele / Véronique Hourdel / Marilyne Davi / Julia Chamot-Rooke / Patrice Vachette / Sébastien Brier / Daniel Ladant / Alexandre Chenal / |
PubMed Abstract | 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 ...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. |
External links | PLoS Biol / PubMed:29287065 / PubMed Central |
Methods | SAS (X-ray synchrotron) |
Structure data | SASDCK9: SASDCL9: |
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