Guzzi C, Alfarano P, Sutkeviciute I, Sattin S, Ribeiro-Viana R, Fieschi F, Bernardi A, Weiser J, Rojo J, Angulo J, Nieto P M
Glycosystems Laboratory. Instituto de Investigaciones Químicas (IIQ)/cicCartuja. CSIC/US, Americo Vespucio, 49, 41092 Sevilla, Spain.
Org Biomol Chem. 2016 Jan 7;14(1):335-44. doi: 10.1039/c5ob02025e. Epub 2015 Nov 27.
DC-SIGN (dendritic cell-specific ICAM-3 grabbing non-integrin) is a C-type lectin receptor (CLR) present, mainly in dendritic cells (DCs), as one of the major pattern recognition receptors (PRRs). This receptor has a relevant role in viral infection processes. Recent approaches aiming to block DC-SIGN have been presented as attractive anti-HIV strategies. DC-SIGN binds mannose or fucose-containing carbohydrates from viral proteins such as the HIV envelope glycoprotein gp120. We have previously demonstrated that multivalent dendrons bearing multiple copies of glycomimetic ligands were able to inhibit DC-SIGN-dependent HIV infection in cervical explant models. Optimization of glycomimetic ligands requires detailed characterization and analysis of their binding modes because they notably influence binding affinities. In a previous study we characterized the binding mode of DC-SIGN with ligand 1, which shows a single binding mode as demonstrated by NMR and X-ray crystallography. In this work we report the binding studies of DC-SIGN with pseudotrisaccharide 2, which has a larger affinity. Their binding was analysed by TR-NOESY and STD NMR experiments, combined with the CORCEMA-ST protocol and molecular modelling. These studies demonstrate that in solution the complex cannot be explained by a single binding mode. We describe the ensemble of ligand bound modes that best fit the experimental data and explain the higher inhibition values found for ligand 2.
DC-SIGN（树突状细胞特异性细胞间黏附分子-3抓取非整合素）是一种C型凝集素受体（CLR），主要存在于树突状细胞（DC）中，是主要的模式识别受体（PRR）之一。该受体在病毒感染过程中具有重要作用。最近提出的旨在阻断DC-SIGN的方法已成为有吸引力的抗HIV策略。DC-SIGN与病毒蛋白（如HIV包膜糖蛋白gp120）中含甘露糖或岩藻糖的碳水化合物结合。我们之前已经证明，带有多个糖模拟配体拷贝的多价树枝状分子能够在宫颈外植体模型中抑制DC-SIGN依赖的HIV感染。糖模拟配体的优化需要对其结合模式进行详细表征和分析，因为它们会显著影响结合亲和力。在之前的一项研究中，我们表征了DC-SIGN与配体1的结合模式，核磁共振（NMR）和X射线晶体学表明其呈现单一结合模式。在这项工作中，我们报告了DC-SIGN与具有更高亲和力的假三糖2的结合研究。通过转移-核Overhauser效应光谱（TR-NOESY）和饱和转移差核磁共振（STD NMR）实验，并结合CORCEMA-ST协议和分子建模对它们的结合进行了分析。这些研究表明，在溶液中，该复合物不能用单一结合模式来解释。我们描述了最符合实验数据的配体结合模式组合，并解释了配体2具有更高抑制值的原因。
