Investigation of the interaction between peanut agglutinin and synthetic glycopolymeric multivalent ligands
作者:Moira Ambrosi、Neil R. Cameron、Benjamin G. Davis、Snjezana Stolnik
DOI:10.1039/b411555b
日期:——
The interaction between synthetic glycoplymers bearing β-D-galactose side groups and the lectin peanut agglutinin (PNA) was investigated by UV-difference spectroscopy and isothermal titration calorimetry (ITC). UV-difference spectroscopy indicated that the polymer–lectin interaction was stronger than that between PNA and either the corresponding monomer, D-galactose or D-lactose. The thermodynamics of binding (K, ΔG, ΔH, ΔS and n) were determined from ITC data by fitting with a two-site, non-cooperative binding model. It was found that the glycopolymer displayed around a 50 times greater affinity for the lectin than the parent carbohydrate, and around 10 times greater than the monomer, on a valency-corrected basis. Binding was found to be entropically driven, and was accompanied by aggregation and precipitation of protein molecules. Furthermore, interesting differences between polymers prepared either from deacetylated monomers, or by deacetylation of pre-formed polymers, were found.
通过紫外差光谱和等温滴定量热法 (ITC) 研究了带有 β-D-半乳糖侧基的合成糖聚合物与凝集素花生凝集素 (PNA) 之间的相互作用。紫外差光谱表明,聚合物与凝集素之间的相互作用强于 PNA 与相应单体 D-半乳糖或 D-乳糖之间的相互作用。结合热力学(K、ΔG、ΔH、ΔS 和 n)是通过拟合两位点非合作结合模型从 ITC 数据确定的。结果发现,在价态校正的基础上,糖聚合物对凝集素的亲和力比母体碳水化合物高约 50 倍,比单体高约 10 倍。发现结合是熵驱动的,并伴随着蛋白质分子的聚集和沉淀。此外,还发现了由脱乙酰单体制备的聚合物或通过预形成聚合物脱乙酰制备的聚合物之间的有趣差异。