Bacterial Lectins and Adhesins: Structures, Ligands and Functions

Abstract

Infection by bacteria is often initiated by the specific recognition of host epithelial surfaces by adhesins and lectins. These glycan binding proteins (GBP) are therefore virulence factors that play a role in the first step of adhesion and invasion. The adhesins are part of organelles, they are generally located at the tip of pili or fimbriae. On the opposite, soluble lectins occur either as individual proteins, or in association with toxins or enzymes. The human targets for bacterial adhesins and lectins are mostly fucosylated human histo-blood groups and/or sialylated epitopes. The binding of lectins and adhesins to host epithelial glycoconjugates is amplified by the multivalent presentation of the binding sites. The analysis of the available crystal structures of bacterial lectins and adhesins helps deciphering the structure/function relationship for this important class of proteins. It is a prerequisite for the development of multivalent high affinity ligands in antibacterial strategies.