Department of Chemistry, University of California - Riverside, Riverside, CA 92521, United States; Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
Department of Chemistry, University of California - Riverside, Riverside, CA 92521, United States.
Int J Biol Macromol. 2019 May 15;129:744-749. doi: 10.1016/j.ijbiomac.2019.02.062. Epub 2019 Feb 13.
Chitin oligosaccharides, composed of homogeneous β(1 → 4)-linked N-acetyl-D-glucosamine (GlcNAc) sequences, is a well-known elicitor of plant immune defense, and also occur as structural elements of chitosan and nodulation (Nod) factor. Detailed microstructure characterization is required for understanding the function mode of these bioactive molecules. Herein, experimental conditions for detection and elucidation of the H NMR resonances of amide groups in chitin oligosaccharides are presented. The binary mixture of 70% HO: 30% DMSO‑d was found to be the optimal solvent for amide proton measurements in homogeneous GlcNAc sequences, facilitating differentiation of the local chemical microenvironments of all four amide groups of the chitin tetrasaccharide. Experimental evidence that anomeric end-effect triggers amide proton resonance differentiation at the adjacent residue has potential to provide important insights into the solution structure of chitin and other amino sugars containing GlcNAc sequences.
壳寡糖由均一的β(1 → 4)-连接的 N-乙酰-D-葡萄糖胺（GlcNAc）序列组成，是一种众所周知的植物免疫防御激发子，也是壳聚糖和结瘤（Nod）因子的结构元素。为了理解这些生物活性分子的作用模式，需要对其进行详细的微观结构表征。本文介绍了检测和阐明壳寡糖中酰胺基团的 1H NMR 共振的实验条件。发现 70% HO: 30% DMSO-d 是均一 GlcNAc 序列中酰胺质子测量的最佳溶剂，有利于区分壳四糖中所有四个酰胺基团的局部化学微环境。端基效应引发相邻残基酰胺质子共振分化的实验证据，有可能为壳聚糖和其他含有 GlcNAc 序列的氨基糖的溶液结构提供重要的见解。
