从生物大分子结构特征解析植物凝集素的多样性

Analyzing the Diversity of Plant Lectins According to Structural Character of Biological Macromolecule

利用计算机模拟分析了植物凝集素结构与功能的特征。结果显示 :(1)植物凝集素在结合糖之前其结构变化是一致的 ;(2 )植物凝集素存在结构上的多样性 ,且可能与其生物功能的多样性有关 ;(3)在结合糖的过程中 ,植物凝集素表面局部结构的构象会有所变化 ,这种变化有利于其识别不同的糖而结合不同的外来糖缀合物 ,发挥其防御功能。对于同一家族的植物凝集素 ,虽然序列同源性较高 ,但在功能上却表现出强烈的多样性。分析表明 :对于生物大分子而言 ,欲完成同一功能 ,不一定结构相同 ;结构相同 。

Mannose specific lectins are widely distributed in higher plants and are believed to play a role in recognition of high mannose type glycans of foreign microorganisms or plant predators. In this paper, we simulated the amino acid residue's structural character of the sugar binding sites of mannose specific binding plant lectins, and calculated and analyzed solvent accessible surface area of the related residue and mean hydrophobicity of the surface patches. Results indicated: (1)Before the plant lectins bind sugar, their conformational variety are consistent; (2)The plant lectins exhibit the structural diversity, which may relate with the diversity of their biological function; (3)During the process of binding sugar, the surface part conformation of the plant lectins can have some variety; this kind of variety may benefit to recognize the plant lectins to the different sugar and bind the differently foreign glycoconjugates, and develop their defense function. To same family plant lectins, although their sequences have high homology, the biological functions have strongly diversity. The structural diversity of mannose specific plant lectins associated with the specific recognition of high mannose type glycans highlights the importance of mannose specific lectins as recognition molecules in higher plants. All results suggest: For biological macromolecule, the function is same, the structure is uncertainly similar; and the structure is similar, the function is uncertainly same.