Gebauer G, Schiltz E, Rüdiger H
Eur J Biochem. 1981 Jan;113(2):319-25. doi: 10.1111/j.1432-1033.1981.tb05069.x.
The complete amino acid sequence of the alpha chain of the mitogenic lectin from Vicia sativa has been determined. The polypeptide was digested by trypsin and chymotrypsin. The fragments were isolated and most of them were sequenced by automatic solid-phase Edman degradation. A total sequence of 52 amino acid residues was obtained which is homologous to the alpha subunits of the lectins from Pisum sativum, Lens culinaris and Vicia faba. The central part (residues 13-32) in particular is completely conserved in all four proteins. In contrast to the three other known sequences, the V. sativa alpha subunit has an additional serine at the N terminus. The differences of the related amino acid sequences of these lectins and concanavalin A, the lectin from Canavalia ensiformis, have been compared using the relative substitution frequency found in homologous proteins by McLachlan. The degree of homology decreases in the order: V. sativa greater than P. sativum greater than V. faba greater than L. culinaris greater than C, ensiformis. Prediction of the secondary structure according to Chou and Fasman reveals that the lectin alpha chain is similar to concanavalin A in the first half of the molecule whereas the C-terminal part apparently tends to form an alpha helix.
已确定来自蚕豆的促有丝分裂凝集素α链的完整氨基酸序列。该多肽用胰蛋白酶和糜蛋白酶消化。分离出片段，其中大部分通过自动固相埃德曼降解进行测序。获得了一个由52个氨基酸残基组成的完整序列，它与来自豌豆、兵豆和蚕豆的凝集素的α亚基同源。特别是中心部分（第13 - 32位残基）在所有这四种蛋白质中完全保守。与其他三个已知序列不同，蚕豆α亚基在N端有一个额外的丝氨酸。使用麦克拉克伦在同源蛋白质中发现的相对取代频率，比较了这些凝集素与刀豆球蛋白A（来自刀豆的凝集素）相关氨基酸序列的差异。同源程度按以下顺序降低：蚕豆＞豌豆＞蚕豆＞兵豆＞刀豆。根据周和法斯曼对二级结构的预测表明，凝集素α链在分子的前半部分与刀豆球蛋白A相似，而C端部分显然倾向于形成α螺旋。
