Osinaga E, Tello D, Batthyany C, Bianchet M, Tavares G, Durán R, Cerveñansky C, Camoin L, Roseto A, Alzari P M
Dept de Bioquímica, Facultad de Medicina, Montevideo, Uruguay.
FEBS Lett. 1997 Jul 21;412(1):190-6. doi: 10.1016/s0014-5793(97)00677-7.
The partial amino acid sequence of the tetrameric isolectin B4 from Vicia villosa seeds has been determined by peptide analysis, and its three-dimensional structure solved by molecular replacement techniques and refined at 2.9 A resolution to a crystallographic R-factor of 21%. Each subunit displays the thirteen-stranded beta-barrel topology characteristic of legume lectins. The amino acid residues involved in metal- and sugar-binding are similar to those of other GalNAc-specific lectins, indicating that residues outside the carbohydrate-binding pocket modulate the affinity for the Tn glycopeptide. Isolectin B4 displays an unusual quaternary structure, probably due to protein glycosylation.
通过肽分析确定了来自野豌豆种子的四聚体异凝集素B4的部分氨基酸序列，并通过分子置换技术解析了其三维结构，以2.9埃分辨率进行精修，晶体学R因子为21%。每个亚基呈现出豆科植物凝集素特有的13链β桶拓扑结构。参与金属和糖结合的氨基酸残基与其他GalNAc特异性凝集素的相似，表明碳水化合物结合口袋外的残基调节对Tn糖肽的亲和力。异凝集素B4呈现出不寻常的四级结构，可能是由于蛋白质糖基化。
