NMR Verification of Structures of Bacterial Saccharide Precursors for Vaccines

约40个单糖和寡糖的中间体制备的hexaslidide-蛋白质结合物已被分析的高分辨率NMR在500 MHz。使用的技术是：一维（1D）1H和1D 13 C NMR。二维（2D）方法，如COSY，TOCSY，和HSQC也被用于选定的情况下，如果需要额外的信息光谱分配。化学结构的验证是基于1D 1H NMR光谱的积分，以及13 C光谱中碳共振的计数，特别是在分离良好的光谱区域，如C=O、芳香族C、C-1、C-N和C-CH 3部分。1D 13 C无失真极化转移增强（DEPT）也用于区分13 CH 2共振与13 CH和13 CH 3的共振。这种简单的光谱编辑技术以反相的13 C共振的形式产生13 CH 2计数，并且特别适用于这些中间体，因为这些结构中酰胺和连接体侧链的混合CH、CH 2、CH 3共振。 在500 MHz下测量的NMR服务光谱已被提供用于鉴定从宋内志贺菌分离的20个多糖片段，包括用于结构研究的亚硝酸脱氨基产物，以及有助于检测样品中的核心多糖的光谱。使用的技术包括1D 1H和13 C NMR，但有时也包括2D COSY，TOCSY和HSQC。在50 ℃的升高的样品温度下进行光谱的采集，以降低溶液的粘度，从而允许测量更清晰的光谱。该技术提供了复杂的指纹图谱，可以与文献数据进行比较，以验证身份。 还测量了从肺炎克雷伯氏菌2型分离的9个级分的服务光谱，包括一系列的3个多糖样品，这些样品已经进行了5、15或30分钟的超声处理以测试分子量降低程序。 一种在S.经1D ~ 1H和~（13）C NMR鉴定为弗氏2a型。

About 40 monosaccharide and oligosaccharide intermediates for the preparation of a hexasaccharide-protein conjugate have been analyzed by high-resolution NMR at 500 MHz. The techniques used were: one-dimensional (1D) 1H and 1D 13C NMR. Two-dimensional (2D) methods such as COSY, TOCSY, and HSQC were also used in selected cases, if additional information on spectral assignments was needed. Validation of the chemical structures was based on integration of the 1D 1H NMR spectra, and on counting of carbon resonances in the 13C spectra, especially in well-separated spectral regions, such as those of the C=O, aromatic C, C-1, C-N, and C-CH3 moieties. 1D 13C Distortionless Enhancement by Polarization Transfer (DEPT) was also used to differentiate 13CH2 resonances from those of 13CH and 13CH3. This simple spectral editing technique yields a 13CH2 count in the form of 13C resonances of inverted phase, and was particularly applicable to these intermediates because of the mixed CH, CH2, CH3 resonances of the amide and linker side-chains in these structures. NMR service spectra measured at 500 MHz have been provided for the identification of 20 polysaccharide fragments isolated from Shigella sonnei, including products of nitrous acid deamination that are being used in structural studies, and spectra that facilitate detection of core polysaccharide in the samples. The techniques used include 1D 1H and 13C NMR, but sometimes 2D COSY, TOCSY, and HSQC, too. Acquisition of the spectra was performed at an elevated sample temperature of 50 C to reduce the viscosity of the solutions, thus permitting the measurement of sharper spectra. The techniques provide complex fingerprint spectra that can be compared with literature data to verify identity. Service spectra were also measured for nine fractions isolated from Klebsiella pneumoniae type 2, including a series of three samples of the polysaccharide that had been subjected to sonication for 5, 15, or 30 minutes to test a molecular weight reduction procedure. One sample of a polysaccharide found in S. flexneri type 2a has been identified by 1D 1H and 13C NMR.