Overproduction, purification and preliminary crystallographic analysis of the carbohydrate-recognition domain of human langerin.

Langerin, a lectin that is specific to Langerhans cells, interacts with glycoconjugates through its carbohydrate-recognition domain (CRD). This carbohydrate binding occurs by an avidity-based mechanism that is enabled by the neck domain responsible for trimerization. Langerin binds HIV through its CRD and thus plays a protective role against its propagation by the internalization of virions in Birbeck granules. Here, the overproduction, purification and crystallization of the langerin CRD is reported. Crystals obtained by the hanging-drop vapour-diffusion method allowed the collection of a complete data set to 1.5 A resolution and belonged to the tetragonal space group P4(2), with unit-cell parameters a = b = 79.55, c = 90.14 A.