Experimental and computational studies of monovalent metal cation–peptide interactions in [M·GlyGlyHis]⁺ (M = Li, Na, K, Rb, Cs, and Ag) complexes

Abstract

[ 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.

Salt-induced Fmoc-tripeptide supramolecular hydrogels: a combined experimental and computational study of the self-assembly

“…36,37 Thus, delving into the mechanism behind the molecular interactions at the atomic level allows us to explore the dynamic reorganization and plasticity within the systems and plays a key role in the development of nanomaterials with specific structure-property-function relationships from a bottom-up perspective. 38 While previous research works studied the peptide self-assembly of pre-organized configurations in the presence of salts using density functional theory (DFT) at the nanosecond scale, 18,[39][40][41] and a maximum peptide : salt mixture molar ratio of 1 : 3, 22,42,43 understanding what happens at the atomic scale and higher peptide : salt concentrations remains a challenge.…”