Specialized iNANO lecture: Study of the CyaA toxin from B.pertussis using a combination of SEC-SAXS and HDX-MS

Patrice Vachette, Institute for Integrative Biology of the Cell (I2BC) Université Paris-Saclay, France

2018.11.09 | Trine Møller Hansen

Date Fri 23 Nov
Time 13:15 14:00
Location iNANO 1590-213, Gustav Wieds Vej 14, 8000 Aarhus C

Patrice Vachette, Institute for Integrative Biology of the Cell (I2BC) Université Paris-Saclay, France

Study of the CyaA toxin from B.pertussis using a combination of SEC-SAXS and HDX-MS

 

The adenylate cyclase toxin (CyaA) plays an essential role in the early stages of respiratory tract colonization by Bordetella pertussis, the causative agent of whooping cough. Secreton and folding of the protein as well as the activation of enzymatic activity following translocation of the catalytic domain directly across the plasma membrane of the target cell all involve disorder-to-order transitions. Using a combination of Small-Angle X-ray Scattering (SAXS) and proton-deuterium exchange monitored by mas spectrometry (HDX-MS), we have studied these transitions in solution.

I will first present the basis of SAXS and its requirements with an emphasis on the coupling of SAXS with Size Exclusion Chromatography (so-called SEC-SAXS) together with a succinct overview of the main modeling methods. A brief introduction to HDX-MS will follow. I will then come to the study of the transition through which calmodulin within the target cell activates the adenylate cyclase activity of the toxin that ultimately leads to cell death. Time permitting, we will examine the Ca-dependent disorder to order transition of the N-terminal part of the molecule that is key to the mechanism of secretion from the bacteria and folding in the extra cellular milieu.

Host: Professor Jan Skov Pedersen, iNANO & dept. of Chemistry, Aarhus University

Specialized iNANO Lectures