[M·GlyGlyHis]+ (M = Li, Na, K, Rb, Cs, and Ag) complexes were generated using the electrospray ionization method and were subjected to collision-induced dissociation. Metal ion loss is the primary dissociation channel for [Cs·GlyGlyHis]+ whereas other complexes yield metal-bound peptide sequence ions and dehydrated ions as the main products. [Li·GlyGlyHis]+ and [Ag·GlyGlyHis]+ also generate product ions that are not observed for other complexes. Density functional theory calculations suggest that metal ion–peptide ligand interaction occurs through covalent interactions in [Li·GlyGlyHis]+ and [Ag·GlyGlyHis]+, and through electrostatic attraction in [Na·GlyGlyHis]+, [K·GlyGlyHis]+, [Rb·GlyGlyHis]+, and [Cs·GlyGlyHis]+. The calculations also suggest that fragmentation behavior of these complexes is affected by charge transfer to the ligand and ion-ligand interaction energy, and to a lesser extent by the ion size.

中文翻译：

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[M·GlyGlyHis]+（M = Li、Na、K、Rb、Cs 和 Ag）配合物中单价金属阳离子-肽相互作用的实验和计算研究

[M·GlyGlyHis]+（M = Li、Na、K、Rb、Cs 和 Ag）复合物是使用电喷雾电离方法生成的，并进行碰撞诱导解离。金属离子损失是 [Cs·GlyGlyHis]+ 的主要解离通道，而其他配合物则产生金属结合的肽序列离子和脱水离子作为主要产物。[Li·GlyGlyHis]+ 和 [Ag·GlyGlyHis]+ 也会产生其他复合物未观察到的产物离子。密度泛函理论计算表明，金属离子-肽配体相互作用通过 [Li·GlyGlyHis]+ 和 [Ag·GlyGlyHis]+ 中的共价相互作用以及 [Na·GlyGlyHis]+、[K·GlyGlyHis]+ 中的静电吸引发生， [Rb·GlyGlyHis]+ 和 [Cs·GlyGlyHis]+。