Structure and mechanism of the osmoregulated choline transporter BetT

• DOI: 10.1126/sciadv.ado6229
• Publication Date: 2024-08-14T18:00:39Z
• Authors: Tianjiao Yang; Yuwei Nian; Huajian Lin; Jing Li; Xiang Lin; Tianming Li; Ruiying Wang; Longfei Wang; Gwyn A. Beattie; Jinru Zhang; Minrui Fan
• Keywords: Betaine; Pseudomonas syringae; Osmotic concentration; Choline

The choline–glycine betaine pathway plays an important role in bacterial survival hyperosmotic environments. Osmotic activation of the choline transporter BetT promotes uptake external for synthesizing osmoprotective glycine betaine. Here, we report cryo–electron microscopy structures Pseudomonas syringae apo and choline-bound states. Our structure shows that forms a domain-swapped trimer with C-terminal domain (CTD) one protomer interacting transmembrane (TMD) neighboring protomer. substrate is bound within tryptophan prism at central part TMD. Together functional characterization, our results suggest species, including plant pathogen P. human aeruginosa , locked low-activity state through CTD-mediated autoinhibition absence osmotic stress, its involves release this autoinhibition.