Rigidified multivalent lactose molecules and their interactions with mammalian galectins: a route to selective inhibitors
作者:Ioannis Vrasidas、Sabine André、Paola Valentini、Corina Böck、Martin Lensch、Herbert Kaltner、Rob M. J. Liskamp、Hans-J. Gabius、Roland J. Pieters
DOI:10.1039/b210923a
日期:2003.2.27
New and rigid multivalent lactose molecules were prepared. The structures contain lactose-2-aminothiazoline units at the periphery that were formed from a cyclisation of the thiourea sulphur onto the triple bond of the spacer. The lactosides were evaluated as inhibitors against lectin binding in a solid phase inhibition assay. In this assay the glycoprotein asialofetuin was immobilized onto the surface of microtiter plate wells, mimicking cell surface presentation, while mammalian galectins-1, -3 or -5 were in solution. Between the three galectins, the folding pattern and sequence are closely related but the topology of presentation of the carbohydrate recognition domains differs. Strong multivalency effects were observed for the tetravalent lactoside in the inhibition of galectin-3 binding with enhancements of almost 4300-fold compared to lactose. Remarkable selectivity was obtained in the inhibition since relative potencies of the tetravalent lactoside with the proto type galectins-1 and -5 did not exceed a factor of 143 relative to lactose. The binding of the lactosides to galectin-3 was also studied by fluorescence spectroscopy with all components in solution. These studies showed no multivalency effects in the inherent binding affinities.
制备了新的刚性多价乳糖分子。该结构的外围含有乳糖-2-氨基噻唑啉单元,这些单元是由硫脲硫在间隔基的三键上环化形成的。在固相抑制测定中将乳糖苷作为凝集素结合的抑制剂进行评估。在该测定中,糖蛋白脱唾液酸胎球蛋白被固定在微量滴定板孔的表面上,模拟细胞表面的呈现,而哺乳动物半乳糖凝集素-1、-3或-5则在溶液中。在三种半乳糖凝集素之间,折叠模式和序列密切相关,但碳水化合物识别域的呈现拓扑不同。观察到四价乳糖苷在抑制半乳糖凝集素-3 结合方面具有强烈的多价效应,与乳糖相比增强了近 4300 倍。由于四价乳糖苷与原型半乳糖凝集素-1和-5的相对效力相对于乳糖不超过143倍,因此在抑制中获得了显着的选择性。还通过溶液中所有组分的荧光光谱研究了乳糖苷与半乳糖凝集素-3 的结合。这些研究表明内在结合亲和力没有多价效应。