Unexpected features in the Protein Data Bank entries 3qd1 and 4i8e: the structural description of the binding of the serine-rich repeat adhesin GspB to host cell carbohydrate receptor is not a solved issue

A recently published crystallographic model of GspB in complex with a disaccharide was proposed to provide insight into the interaction of the S. gordonii adhesin with the cell sialyl-T antigen from host cells. However, a close inspection of this model revealed that in this complex a buffer molecule was mistaken for the disaccharide. As a consequence, this complex provides no information regarding the interaction of GspB with host cell receptors.