Weiß Alexander, Dutschke Manuel, Vogt Carla, Zuber Jan
Institute of Analytical Chemistry, TU Bergakademie Freiberg, Lessingstraße 45, Freiberg 09599, Germany.
MFPA Weimar-Materials Research and Testing Institute Weimar, Coudraystraße 9, Weimar 99423, Germany.
ACS Omega. 2024 Oct 31;9(45):45309-45318. doi: 10.1021/acsomega.4c06976. eCollection 2024 Nov 12.
In recent years, binding studies to determine complex stabilities and selectivities of artificial carbohydrate receptors with glycosides have been mainly performed using H NMR, isothermal titration calorimetry (ITC), and other spectroscopic titration techniques. Native electrospray ionization (ESI) mass spectrometry is used only to verify the complex stoichiometries, although determination of dissociation constants is also possible. Herein, the binding of a 1,3,5-substituted 2,4,6-triethylbenzene-based receptor (CHR) to four alkyl-β-d-glucosides with varying alkyl side chain lengths (methyl (MGP), hexyl (HGP), octyl (OGP), and dodecyl (DGP)-β-d-glucosides), which was analyzed by ESI Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) under optimized spray conditions in both ion modes, is reported. The complexes of the receptor with different sugars could be detected in 1:1 and 2:1 stoichiometries. Dissociation constants calculated for the 1:1 complexes showed a stability trend depending on the length of the alkyl side chain of the sugar: CHR:DGP > CHR:OGP > CHR:HGP > CHR:MGP. Gas phase stabilities determined by CID-MS confirm this relative trend in binding affinities. These findings substantiate the validity and applicability of ESI-MS as a method for investigating noncovalent complex stabilities and thus support research in the field of molecular recognition of carbohydrates by artificial receptors.
近年来，主要使用核磁共振氢谱（¹H NMR）、等温滴定量热法（ITC）及其他光谱滴定技术开展结合研究，以确定人工碳水化合物受体与糖苷的复合物稳定性和选择性。尽管也可以测定解离常数，但天然电喷雾电离（ESI）质谱仅用于验证复合物的化学计量比。本文报道了在两种离子模式下的优化喷雾条件下，通过ESI傅里叶变换离子回旋共振质谱（ESI-FT-ICR-MS）分析的基于1,3,5-取代的2,4,6-三乙苯的受体（CHR）与四种具有不同烷基侧链长度的烷基-β-D-葡萄糖苷（甲基（MGP）、己基（HGP）、辛基（OGP）和十二烷基（DGP）-β-D-葡萄糖苷）的结合情况。受体与不同糖类的复合物可以1:1和2:1的化学计量比被检测到。为1:1复合物计算的解离常数显示出一种取决于糖类烷基侧链长度的稳定性趋势：CHR:DGP > CHR:OGP > CHR:HGP > CHR:MGP。通过碰撞诱导解离质谱（CID-MS）测定的气相稳定性证实了这种结合亲和力的相对趋势。这些发现证实了ESI-MS作为研究非共价复合物稳定性方法的有效性和适用性，从而支持了人工受体对碳水化合物分子识别领域的研究。
