Fig. 1.

Bacterial cell walls are coated with a diverse array of glycan structures. (a) Gram-negative bacteria contain both an inner membrane (IM) and an outer membrane (OM). The space between the membranes is rigidified by the peptidoglycan. Embedded in the outer membrane are lipopolysaccharide (LPS), capsular polysaccharide (CPS), and glycoproteins. (b) Gram-positive bacteria contain only one membrane (M), which is reinforced with a thick coating of peptidoglycan. Capsular polysaccharides, teichoic acids, and glycoproteins are found on the periphery of the cell. (c) Mycobacteria are Gram-positive bacteria that contain distinctive glycans on their cells, including lipoarabinomannan, arabinogala ctan, mycolic acid, and trehalose-linked lipids. Image is not to scale.