Gating by ionic strength and safety check by cyclic-di-AMP in the ABC transporter OpuA

• DOI: 10.1126/sciadv.abd7697
• Publication Date: 2020-11-19T01:00:36Z
• Authors: Hendrik R. Sikkema; Marco van den Noort; Jan Rheinberger; Marijn de Boer; Sabrina T. Krepel; Gea K. Schuurman-...; Cristina Paulino; Bert Poolman
• Keywords: 0301 basic medicine; 03 medical and health sciences; Research Articles

(Micro)organisms are exposed to fluctuating environmental conditions, and adaptation stress is essential for survival. Increased osmolality (hypertonicity) causes outflow of water loss turgor dangerous if the cell not capable rapidly restoring its volume. The osmoregulatory adenosine triphosphate-binding cassette transporter OpuA restores volume by accumulating large amounts compatible solute. gated ionic strength inhibited second messenger cyclic-di-AMP, a molecule recently shown affect many cellular processes. Despite master regulatory role structural functional insights into how regulates (transport) proteins on molecular level lacking. Here, we present high-resolution cryo-electron microscopy structures in vitro activity assays that show osmoregulator activated high cyclic-di-AMP acts as backstop prevent unbridled uptake solutes.