Natural-abundance, 13C-n.m.r. spectroscopy was used to study the mode of binding of Gd3+ to mono-O-glycosylated L-serine and tripeptides variously composed of Gly and L-Thr. When the amino and carboxyl groups of the amino acid are not blocked, strong interaction of Gd3+ with them is observed; this is also readily apparent with some related, nonglycosylated peptides. When the amino and carboxyl groups
使用自然丰度13C-nmr光谱研究Gd3 +与单-O-糖基化
L-丝氨酸和由Gly和L-Thr组成的三肽的结合方式。当
氨基酸的
氨基和羧基没有被封闭时,观察到Gd3 +与它们的强相互作用;对于一些相关的,非糖基化的肽,这也是显而易见的。当
氨基酸的
氨基和羧基被封闭时,Gd3 +与含α-D-Galp的糖肽的糖苷氧原子(O-3)和O-2'以及与O-3和N-的显着相互作用观察到含有α-D-GalpNAc的糖肽的2'。与糖基的O-4'和O-6'弱相互作用也是可能的。尽管
氨基酸受到保护,但这些
金属离子与
碳水化合物的相互作用仍可能在一定程度上被介导,