Kotena Zahrabatoul Mosapour, Fattahi Alireza
Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran, Iran.
Department of Chemistry, Sharif University of Technology, P.O. Box 11365-9516, Tehran, Iran.
J Mol Graph Model. 2020 Jul;98:107612. doi: 10.1016/j.jmgm.2020.107612. Epub 2020 Apr 8.
The derivatives of glucose such as glucosamine (β-D-GlcN) and N-acetyl-D-β-glucosamine (GlcNAc) are significant in several biological systems. D-GlcN has been used widely to treat osteoarthritis in humans and animal models as well as GlcNAc has been proposed as a treatment for autoimmune diseases. The DFT/B3LYP/6-311++G (d,p) method as well as QTAIM and NBO analyses were used to the acidity values of D-GlcN and GlcNAc sugars and their complexes with alkali ions in the gas phase. The Li, Na and K prefer bi-dentate chelate in these complexes. The computed results indicate that metal ion affinity (MIA) in GlcNAc is higher than that in D-GlcN. There are direct correlations between the MIA values of D-GlcN and GlcNAc sugars and the atomic numbers of Li, Na, and K. The calculated acidity values for GlcNAc at C-NH and C-HO sites are 331 and 333 kcal mol, respectively. Whereas the calculated acidity values for D-GlcN at C-NH and C-HO sites are 365 and 372 kcal mol, respectively. The AIM and NBO analyses indicate the presence of intramolecular H-bonds in GlcNAc sugar in both its neutral form and conjugate base; whereas D-GlcN indicates intramolecular H-bonds in only its conjugate base.
葡萄糖的衍生物，如氨基葡萄糖（β-D-葡糖胺）和N-乙酰-D-β-葡萄糖胺（GlcNAc）在多个生物系统中具有重要意义。D-葡糖胺已被广泛用于治疗人类和动物模型中的骨关节炎，并且有人提出GlcNAc可用于治疗自身免疫性疾病。采用DFT/B3LYP/6-311++G(d,p)方法以及QTAIM和NBO分析，来计算D-葡糖胺和GlcNAc糖及其与碱金属离子在气相中的络合物的酸度值。在这些络合物中，锂、钠和钾更倾向于形成双齿螯合物。计算结果表明，GlcNAc中的金属离子亲和力（MIA）高于D-葡糖胺中的。D-葡糖胺和GlcNAc糖的MIA值与锂、钠和钾的原子序数之间存在直接相关性。GlcNAc在C-NH和C-HO位点的计算酸度值分别为331和333 kcal/mol。而D-葡糖胺在C-NH和C-HO位点的计算酸度值分别为365和372 kcal/mol。AIM和NBO分析表明，GlcNAc糖在其中性形式和共轭碱中均存在分子内氢键；而D-葡糖胺仅在其共轭碱中存在分子内氢键。
