X-ray crystallography of lectins

In the last decade we have witnessed an explosive growth of the number of proteins identified with carbohydrate binding functions. Concomitantly a large number of three dimensional structures of lectins and their carbohydrate complexes have become available. Still many other proteins classified and categorized under different names may be recognized as lectins in a near future. Most probably we have only witnessed the tip of the iceberg and with the full realization of the genome projects many new lectins, folds and carbohydrate binding modes may become apparent . Rather than giving a lengthy and encyclopaedic description of a large set of lectin structures, we opted to focus on a few families that are well documented: leguminous lectins, lectins involved in glycoprotein trafficking, bacterial adhesins, animal C-type lectins, galectins and viral adhesins. From these we try to distil structural principles that underlay selectivity and affinity.