Illustration of the surface glycan-binding protein BO2743 from the bacterium Bacteroides ovatus in complex with a mixed-linked gluco-nonasaccharide. This bacterium is a normal part of the human gut flora where it uses the dietary carbohydrates beta-glucans as a source of energy. The surface glycan-binding proteins recognise and bind to the beta-glucans so that they can be transported into the cell to be metabolised.