Calcium-mediated lectin <p>This entry represents calcium-mediated lectins. Structures have been determined for both fucose-binding lectin II (PA-IIL) [<cite idref="PUB00022383"/>] and mannose-specific lectin II (RS-IIL) [<cite idref="PUB00031862"/>]. These proteins have homologous structures, their monomers consisting of a 9-stranded beta sandwich with Greek-key topology. Each monomer contains two calcium ions that mediate an exceptionally high binding affinity to the monosaccharide ligand in a recognition mode unique among carbohydrate-protein interactions. In <taxon tax_id="287">Pseudomonas aeruginosa</taxon>, PA-IIL contributes to the pathogenic virulence of the bacterium, functioning as a tetramer when binding fucose [<cite idref="PUB00013173"/>]. In the plant pathogen <taxon tax_id="305">Ralstonia solanacearum</taxon> (Pseudomonas solanacearum), RS-IIL recognises fucose, but displays much higher affinity to mannose and fructose, which is opposite to the preference of PA-IIL. </p>