Sanz-Aparicio J, Hermoso J, Grangeiro T B, Calvete J J, Cavada B S
Instituto de Química-Física Rocasolano CSIC, Departamento de Cristalografía, Madrid, Spain.
FEBS Lett. 1997 Mar 17;405(1):114-8. doi: 10.1016/s0014-5793(97)00137-3.
Canavalia brasiliensis lectin was isolated from the seeds of a Brazilian autochthonous Leguminosae plant. Despite extensive amino acid sequence similarity with Concanavalin A, C. brasiliensis lectin exerts in vitro and in vivo cellular effects that are markedly different from those displayed by Concanavalin A. We have solved the crystal structure of the C. brasiliensis lectin at 3.0 A resolution. The three-dimensional structure of the lectin monomer can be superimposed onto that of Concanavalin A with a root-mean-square deviation for all C alpha atoms of 0.65 A. However, this parameter is 0.84 and 1.62 A when the C. brasiliensis lectin dimer and tetramer, respectively, are compared with the same structures of Concanavalin A. We suggest that these differences in quaternary structure may account for the different biological properties of these two highly related Leguminosae lectins.
巴西刀豆凝集素是从一种巴西本土豆科植物的种子中分离出来的。尽管其氨基酸序列与伴刀豆球蛋白A有广泛的相似性，但巴西刀豆凝集素在体外和体内产生的细胞效应与伴刀豆球蛋白A明显不同。我们已解析出巴西刀豆凝集素在3.0埃分辨率下的晶体结构。凝集素单体的三维结构可以与伴刀豆球蛋白A的结构叠加，所有Cα原子的均方根偏差为0.65埃。然而，当分别将巴西刀豆凝集素二聚体和四聚体与伴刀豆球蛋白A的相同结构进行比较时，该参数分别为0.84埃和1.62埃。我们认为，四级结构的这些差异可能解释了这两种高度相关的豆科凝集素不同的生物学特性。
