Open AccessFacile generation of tripeptide radical cations in vacuo via intramolecular electron transfer in CuII tripeptide complexes containing sterically encumbered terpyridine ligands
Author(s) -
Ivan K. Chu,
Corey N. W. Lam,
S. O. Siu
Publication year - 2005
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2005.01.026
Subject(s) - chemistry , tripeptide , steric effects , intramolecular force , heteroatom , ligand (biochemistry) , terpyridine , stereochemistry , electron transfer , electron transfer dissociation , crystallography , peptide , photochemistry , organic chemistry , ring (chemistry) , mass spectrometry , biochemistry , receptor , chromatography , tandem mass spectrometry , metal
Molecular radical cations of tripeptides of the form glycylglycyl(residue X) (GGX*+) are produced by the collision-induced, intramolecular one-electron transfer of [Cu(II)(L)GGX]*2+ complexes (L = triamine ligand). We demonstrate, for the first time, the formation of molecular radical cations of all of the aliphatic, basic, aromatic, acidic, and some heteroatom-bearing GGX tripeptides, albeit inefficiently in some cases, by altering the structure of the auxiliary polyamine ligand bound to the copper atom. The design of the ligand allows exquisite control over the nature of the dissociation pathway. Steric hindrance of bulky groups in the ligand affects the binding of the peptide to the copper ion; this interaction is an important factor in determining whether the electron transfer pathway predominates.