Van Damme E J, Goossens K, Smeets K, Van Leuven F, Verhaert P, Peumans W J
Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium.
Plant Physiol. 1995 Apr;107(4):1147-58. doi: 10.1104/pp.107.4.1147.
A new lectin was purified from tubers of Arum maculatum L. by affinity chromatography on immobilized asialofetuin. Although this lectin is also retained on mannose-Sepharose 4B, under the appropriate conditions free mannose is a poor inhibitor of its agglutination activity. Pure preparations of the Arum lectin apparently yielded a single polypeptide band of approximately 12 kD upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, N-terminal sequencing of the purified protein combined with molecular cloning of the lectin have shown that the lectin is composed of two different 12-kD lectin subunits that are synthesized on a single large precursor translated from an mRNA of approximately 1400 nucleotides. Lectins with similar properties were also isolated from the Araceae species Colocasia esculenta (L.) Schott, Xanthosoma sagittifolium (L.) Schott, and Dieffenbachia sequina Schott. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration of the different Araceae lectins have shown that they are tetrameric proteins composed of lectin subunits of 12 to 14 kD. Interestingly, these lectins are the most prominent proteins in the tuber tissue. Evidence is presented that a previously described major storage protein of Colocasia tubers corresponds to the lectin.
通过固定化去唾液酸胎球蛋白亲和层析法，从黄斑海芋的块茎中纯化出一种新的凝集素。尽管这种凝集素也能保留在甘露糖-琼脂糖4B上，但在适当条件下，游离甘露糖对其凝集活性的抑制作用较弱。在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳中，黄斑海芋凝集素的纯制品显然产生了一条约12 kD的单一多肽带。然而，纯化蛋白的N端测序与凝集素的分子克隆表明，该凝集素由两个不同的12-kD凝集素亚基组成，这两个亚基在由约1400个核苷酸的mRNA翻译而来的单一大型前体上合成。从天南星科植物芋（Colocasia esculenta (L.) Schott）、黄魔芋（Xanthosoma sagittifolium (L.) Schott）和花叶万年青（Dieffenbachia sequina Schott）中也分离出了具有相似性质的凝集素。不同天南星科凝集素的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和凝胶过滤显示，它们是由12至14 kD的凝集素亚基组成的四聚体蛋白。有趣的是，这些凝集素是块茎组织中最主要的蛋白质。有证据表明，之前描述的芋块茎中的一种主要贮藏蛋白与凝集素相对应。
