Wright L M, Van Damme E J, Barre A, Allen A K, Van Leuven F, Reynolds C D, Rouge P, Peumans W J
School of Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK.
Biochem J. 1999 May 15;340 ( Pt 1)(Pt 1):299-308.
Two lectins have been isolated from bluebell (Scilla campanulata) bulbs. From their isolation by affinity chromatography, they are characterized as a mannose-binding lectin (SCAman) and a fetuin-binding lectin (SCAfet). SCAman preferentially binds oligosaccharides with alpha(1,3)- and alpha(1,6)-linked mannopyranosides. It is a tetramer of four identical protomers of approx. 13 kDa containing 119 amino acid residues; it is not glycosylated. The fetuin-binding lectin (SCAfet), which is not inhibited by any simple sugars, is also unglycosylated. It is a tetramer of four identical subunits of approx. 28 kDa containing 244 residues. Each 28 kDa subunit is composed of two 14 kDa domains. Both lectins have been cloned from a cDNA library and sequenced. X-ray crystallographic analysis and molecular modelling studies have demonstrated close relationships in sequence and structure between these lectins and other monocot mannose-binding lectins. A refined model of the molecular evolution of the monocot mannose-binding lectins is proposed.
从蓝钟花（Scilla campanulata）球茎中分离出了两种凝集素。通过亲和色谱法对它们进行分离后，其特征分别为一种甘露糖结合凝集素（SCAman）和一种胎球蛋白结合凝集素（SCAfet）。SCAman优先结合具有α(1,3)-和α(1,6)-连接的甘露吡喃糖苷的寡糖。它是由四个约13 kDa的相同亚基组成的四聚体，含有119个氨基酸残基；它未被糖基化。胎球蛋白结合凝集素（SCAfet）不受任何单糖抑制，也未被糖基化。它是由四个约28 kDa的相同亚基组成的四聚体，含有244个残基。每个28 kDa的亚基由两个14 kDa的结构域组成。这两种凝集素均已从cDNA文库中克隆并测序。X射线晶体学分析和分子建模研究表明，这些凝集素与其他单子叶甘露糖结合凝集素在序列和结构上存在密切关系。提出了单子叶甘露糖结合凝集素分子进化的精细模型。
