Ribeiro João P, Diercks Tammo, Jiménez-Barbero Jesús, André Sabine, Gabius Hans-Joachim, Cañada Francisco Javier
Centre de Recherches sur les Macromolécules Végétales, UPR5301, CNRS-Université Grenoble Alpes, BP53, 38041 Grenoble cédex 09, France.
CIC bioGUNE, Bizkaia Technological Park, Building 800, 48160 Derio, Spain.
Biomolecules. 2015 Nov 13;5(4):3177-92. doi: 10.3390/biom5043177.
The characterization of the binding of reducing carbohydrates present as mixtures of anomers in solution to a sugar recepor (lectin) poses severe difficulties. In this situation, NMR spectroscopy enables the observation of signals for each anomer in the mixture by applying approaches based on ligand observation. Saturation transfer difference (STD) NMR allows fast and efficient screening of compound mixtures for reactivity to a receptor. Owing to the exceptionally favorable properties of (19)F in NMR spectroscopy and the often complex ¹H spectra of carbohydrates, (19)F-containing sugars have the potential to be turned into versatile sensors for recognition. Extending the recently established ¹H → ¹H STDre(19)F-NMR technique, we here demonstrate its applicability to measure anomeric selectivity of binding in a model system using the plant lectin concanavalin A (ConA) and 2-deoxy-2-fluoro-d-mannose. Indeed, it is also possible to account for the mutual inhibition between the anomers on binding to the lectin by means of a kinetic model. The monitoring of (19)F-NMR signal perturbation disclosed the relative activities of the anomers in solution and thus enabled the calculation of their binding affinity towards ConA. The obtained data show a preference for the α anomer that increases with temperature. This experimental approach can be extended to others systems of biomedical interest by testing human lectins with suitably tailored glycan derivatives.
对溶液中以异头物混合物形式存在的还原性碳水化合物与糖受体（凝集素）结合的表征存在严重困难。在这种情况下，核磁共振光谱法通过应用基于配体观测的方法，能够观测混合物中各异头物的信号。饱和转移差（STD）核磁共振技术可快速有效地筛选化合物混合物与受体的反应性。由于氟-19在核磁共振光谱中具有特别有利的性质，且碳水化合物的氢谱往往很复杂，含氟-19的糖类有潜力成为通用的识别传感器。扩展最近建立的氢→氢STDre(19)F-核磁共振技术，我们在此证明了其在使用植物凝集素伴刀豆球蛋白A（ConA）和2-脱氧-2-氟-D-甘露糖的模型系统中测量结合异头物选择性的适用性。实际上，通过动力学模型也可以解释异头物在与凝集素结合时的相互抑制作用。对氟-19核磁共振信号扰动的监测揭示了溶液中异头物的相对活性，从而能够计算它们对ConA的结合亲和力。所得数据表明对α异头物的偏好随温度升高而增加。通过用适当定制的聚糖衍生物测试人凝集素，这种实验方法可扩展到其他具有生物医学意义的系统。
