Saturation transfer difference NMR and computational modeling of a sialoadhesin-sialyl lactose complex
Saturation transfer difference NMR and computational modeling of a sialoadhesin-sialyl lactose complex
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DOI：
10.1016/j.carres.2003.09.021
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发表时间：
2004-01-22
影响因子：
3.1
通讯作者：
Peters, T
中科院分区：
文献类型：
--
作者：
Bhunia, A;Jayalakshmi, V;Peters, T
单凝集素是与细胞表面上的唾液酸结合的I型凝集素家族。唾液酸粘附素（siglec-1）在炎性巨噬细胞中以高得多的水平表达，并特异性结合聚糖链的α-2，3-唾液酸化的N-乙酰乳糖胺残基。末端二糖α-D-Neu 5Ac-（2 -> 3）-β-D-Gal被认为是唾液酸粘附素识别的主要表位。为了理解这种生物识别反应的基础，我们将NMR实验与分子建模研究相结合。我们采用饱和转移差（STD）NMR实验以原子分辨率表征α-2，3-唾液酸化乳糖，α-D-Neu 5Ac-（2 -> 3）-β-D-Gal-（1 -> 4）-D-Glc 1与唾液酸粘附素的结合表位。实验结果进行了比较，一个计算对接模型和X-射线数据的唾液酸乳糖和sialoadhesin的复杂。数据显示，唾液酸粘附素主要识别N-乙酰神经氨酸和1的半乳糖部分的一小部分。唾液酸粘附素与唾液酸乳糖1的复合物的晶体结构被用作使用FIexiDock算法的建模研究的基础。生成的模型与原始晶体结构非常相似。因此，使用X射线数据预测采用CORCEMA-STD方案的理论STD值。实验和理论STD值之间的良好一致性表明，组合的建模/STD NMR方法产生了水溶液中唾液酸粘附素与α-D-Neu 5Ac-（2 -> 3）-β-D-Gal-（1 -> 4）-D-Glc 1的复合物的可靠结构模型。(C)2003爱思唯尔有限公司。保留所有权利。
The siglecs are a family of I-type lectins binding to sialic acids on the cell surface. Sialoadhesin (siglec-1) is expressed at much higher levels in inflammatory macrophages and specifically binds to alpha-2,3-sialylated N-acetyl lactosamine residues of glycan chains. The terminal disaccharide alpha-D-Neu5Ac-(2 --> 3)-beta-D-Gal is thought to be the main epitope recognized by sialoadhesin. To understand the basis of this biological recognition reaction we combined NMR experiments with a molecular modeling study. We employed saturation transfer difference (STD) NMR experiments to characterize the binding epitope of alpha-2,3-sialylated lactose, alpha-D-Neu5Ac-(2 --> 3)-beta-D-Gal-(1 --> 4)-D-Glc 1 to sialoadhesin at atomic resolution. The experimental results were compared to a computational docking model and to X-ray data of a complex of sialyl lactose and sialoadhesin. The data reveal that sialoadhesin mainly recognizes the N-acetyl neuraminic acid and a small part of the galactose moiety of 1. The crystal structure of a complex of sialoadhesin with sialyl lactose 1 was used as a basis for a modeling study using the FIexiDock algorithm. The model generated was very similar to the original crystal structure. Therefore, the X-ray data were used to predict theoretical STD values utilizing the CORCEMA-STD protocol. The good agreement between experimental and theoretical STD values indicates that a combined modeling/STD NMR approach yields a reliable structural model for the complex of sialoadhesin with alpha-D-Neu5Ac-(2 --> 3)-beta-D-Gal-(1 --> 4)-D-Glc 1 in aqueous solution. (C) 2003 Elsevier Ltd. All rights reserved.