Plant lectins are a large group of carbohydrate binding proteins of non-immune origin that act deciphering specifically glycocodes encoded in the structure of glycans.  The interaction of lectins and carbohydrates play biological roles in cellular processes, such as cell communication, host defense, fertilization, development, parasitic infection, tumor metastasis, and plant defense against herbivores and pathogens. They are ubiquitous in animals, plants and microorganisms. Over than 250 three-dimensional structures of lectins from diverse sources are available and legume lectins represent a significant part of these proteins. Lectins shares a common structural fold but they may differ in their carbohydrate specificities.
Fucose binding lectins are widespread among microorganisms, animals and plants, including Pseudomonas aeruginosa lectin (PA-IIL), Anguilla Anguilla agglutinin (AAA), Morone saxatilis agglutinin (MsaFBP32), Chromobacterium violaceum lectin (CV-IIL), Ralstonia solanacearum (RS-IIL), Ulex europaeus agglutinin (UEA-I) and Lotus tetragonolobus agglutinin (LTA).
LTA is a member of the legume family (Leguminosae, Papilionoideae, Loteae) of lectins, which have been widely used to explore the properties of membranes from both normal and transformed cells. LTA is a glycoprotein containing 240 amino acid residues with a molecular mass of 26,273.17 Da.
Small crystals of LTA appeared in 0.1 M Tris-HCl pH 8.5 containing 8% of iso-propanol and 16% PEG 4000. LTA crystals diffracted to a maximum resolution of 2.0 Å using synchrotron radiation source (LNLS, Campinas – Brasil). The complete data set (150 frames) was indexed, integrated and scaled in a resolution range of 40.42 - 2.0 Å.  LTA crystals are monoclinic belonging to the P2₁ space group with unit cell parameters of a=68,89, b=65.83, c=102.53 Å and a = g = 90º and b = 92º. The volume of unit cell is 464772.31 A³ with a V_M of 2.2 ųDa^-1. LTA crystal contains one tetramer per asymmetric unit.