Thermodynamic, kinetic, and electron microscopy studies of concanavalin A and Dioclea grandiflora lectin cross-linked with synthetic divalent carbohydrates
Thermodynamic, kinetic, and electron microscopy studies of concanavalin A and Dioclea grandiflora lectin cross-linked with synthetic divalent carbohydrates
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DOI：
10.1074/jbc.m412827200
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发表时间：
2005-03-11
影响因子：
4.8
通讯作者：
Brewer, CF
中科院分区：
文献类型：
--
作者：
Dam, TK;Oscarson, S;Brewer, CF
刀豆凝集素伴刀豆球蛋白A（ConA）和大花吊兰（Dioclea grandiflora）凝集素（DGL）是吊兰亚科（Diocleinae subtribe）的高度同源的Man/Glc特异性成员。这两种凝集素结合，交联，并沉淀具有多个终端非还原Man残基的碳水化合物。本研究探讨了ConA和DGL与一系列合成的二价碳水化合物的结合和交联相互作用，所述二价碳水化合物具有在末端α-吡喃甘露糖苷残基之间具有增加的灵活性和长度的间隔基团。等温滴定微量热法被用来确定热力学的结合的两个凝集素的二价类似物，和动力学光散射和电子显微镜研究被用来表征的交联相互作用的凝集素与碳水化合物。结果表明，具有柔性间隔基团之间的两个末端的Man残基的二价类似物具有更高的亲和力的两种凝集素相比，与非柔性间隔基团。此外，尽管ConA和DGL具有高度同源性，但它们与二价类似物的交联和沉淀动力学表现出差异。电子显微镜显示的损失有组织的交联晶格的两个凝集素与类似物具有增加的距离之间的终端曼残基。对于每种凝集素，类似物的晶格模式的损失是不同的。这些结果对生物系统中凝集素与多价糖受体的相互作用具有重要意义。
The jack bean lectin concanavalin A (ConA) and the Dioclea grandiflora lectin (DGL) are highly homologous Man/Glc-specific members of the Diocleinae subtribe. Both lectins bind, cross-link, and precipitate with carbohydrates possessing multiple terminal nonreducing Man residues. The present study investigates the binding and cross-linking interactions of ConA and DGL with a series of synthetic divalent carbohydrates that possess spacer groups with increasing flexibility and length between terminal alpha-mannopyranoside residues. Isothermal titration microcalorimetry was used to determine the thermodynamics of binding of the two lectins to the divalent analogs, and kinetic light scattering and electron microscopy studies were used to characterize the cross-linking interactions of the lectins with the carbohydrates. The results demonstrated that divalent analogs with flexible spacer groups between the two terminal Man residues possess higher affinities for the two lectins as compared with those with inflexible spacer groups. Furthermore, despite their high degree of homology, ConA and DGL exhibit differences in their kinetics of cross-linking and precipitation with the divalent analogs. Electron microscopy shows the loss of organized cross-linked lattices of the two lectins with analogs possessing increased distance between the terminal Man residues. The loss of lattice patterns with the analogs is distinct for each lectin. These results have important implications for the interactions of lectins with multivalent carbohydrate receptors in biological systems.