Lemieux R U, Wong T C, Liao J, Kabat E A
Mol Immunol. 1984 Sep;21(9):751-9. doi: 10.1016/0161-5890(84)90161-5.
Evidence is provided that the trisaccharide beta DGal(1----4)beta DGlcNAc(1----6)beta DGal is bound by the monoclonal anti-I Ma antibody beginning with a basically nonpolar cleft at the surface of the protein which comes into contact with a weakly polar region of the trisaccharide that extends from the C-5 methylene group of the reducing unit about the surfaces involving the acetamido grouping and the OH-3' of the beta DGlcNAc unit intramolecularly hydrogen bonded to the O-5'' of the nonreducing beta DGal unit and up to the C-5'' methylene group. The combining site then terminates with a polar grouping at its periphery which is disposed to react with OH-6'' and likely OH-4'' in a highly specific manner. The hydroxyl groups at positions 1, 2, 3, 4, 6', 3'' and 4'' remain in contact with the aq. phase. This conclusion was deduced from the relative potencies as inhibitors of a wide number of synthetic compounds that bear varying structural relationships to the trisaccharide. It appears that the stability of the complex is mainly related to attractive interactions between two large complementary and essentially hydrophobic surfaces relative to those when these surfaces are exposed to water.
有证据表明，三糖β-D-半乳糖（1→4）β-D-氨基葡萄糖（1→6）β-D-半乳糖与单克隆抗-I Ma抗体结合，起始于蛋白质表面一个基本非极性的裂缝，该裂缝与三糖的一个弱极性区域接触，该弱极性区域从还原单元的C-5亚甲基开始，围绕涉及乙酰氨基基团和β-D-氨基葡萄糖单元的OH-3'的表面，分子内氢键连接到非还原β-D-半乳糖单元的O-5''，直至C-5''亚甲基。结合位点然后在其外围以一个极性基团终止，该极性基团倾向于以高度特异性的方式与OH-6''以及可能的OH-4''反应。1、2、3、4、6'、3''和4''位的羟基与水相保持接触。这个结论是从大量与三糖具有不同结构关系的合成化合物作为抑制剂的相对效力推导出来的。看来，复合物的稳定性主要与两个大的互补且基本上疏水的表面之间的吸引相互作用有关，相对于这些表面暴露于水时的情况而言。
