Glycan recognition by the Bacteroidetes Sus-like systems

► The Bacteroidetes of the human gut utilize Sus-like systems for glycan uptake. ► SusD-like proteins have an α-helical fold and bind glycans on the cell surface. ► SusD-like proteins may be involved in passing oligosaccharides to a TonB-porin for transport into the periplasm. ► Hybrid two component systems (HTCS) that control Sus genes have two classes of sensor domains that recognize glycan signal molecules. ► Signal transduction across the membrane in HTCS likely differs from classical two-component systems.