Ramsden J J, Wright C S
Department of Biophysical Chemistry, Biozentrum, Basle, Switzerland.
Glycoconj J. 1995 Apr;12(2):113-21. doi: 10.1007/BF00731354.
A novel integrated optical technique is used to monitor the kinetics of incorporation of glycophorin A (GPA) from solution into a planar dimyristoylphosphatidylcholine-cholesterol bilayer membrane, and the subsequent binding of wheat germ agglutinin (WGA) to the membrane-incorporated GPA. The technique significantly improves the attainable accuracy of kinetic measurements. The number of bound molecules can be determined to a precision of ca +/- 80 mol microns-2. Our results show that GPA incorporates spontaneously into the bilayer. Binding of WGA to GPA is optimal in the presence of human serum albumin, and can be reversed by N-acetyl-D-glucosamine. The kinetics of the binding are consistent with the presence of two classes of kinetically distinguishable binding sites with association rates of 2.0 x 10(4) and 9.6 x 10(2) M-1 s-1, and dissociation rates of 2.7 x 10(-3) s-1 and < 10(-5) s-1, respectively. A stoichiometry of 4 WGA monomers per GPA monomer was determined as characteristic of the overall binding interaction.
一种新型的集成光学技术被用于监测糖蛋白A（GPA）从溶液中掺入平面二肉豆蔻酰磷脂酰胆碱 - 胆固醇双层膜的动力学过程，以及随后麦胚凝集素（WGA）与膜结合的GPA的结合情况。该技术显著提高了动力学测量可达到的精度。结合分子的数量可以精确到约±80 mol µm⁻²。我们的结果表明，GPA能自发地掺入双层膜中。在人血清白蛋白存在的情况下，WGA与GPA的结合最为理想，并且可以被N - 乙酰 - D - 葡萄糖胺逆转。结合动力学与存在两类动力学上可区分的结合位点一致，其缔合速率分别为2.0×10⁴和9.6×10² M⁻¹ s⁻¹，解离速率分别为2.7×10⁻³ s⁻¹和<10⁻⁵ s⁻¹。确定每一个GPA单体有4个WGA单体的化学计量比是整体结合相互作用的特征。
