Computational Evidence for Electron Delocalization in Fixed-Charge Tagged Peptide Dications upon Electron Capture Transfer

摘要

Substantial interactions resulting in delocalization of unpaired e~(-) density were predicted for charge-tagged peptides in which the local recombination energy of the fixed-charged pyridinium tag and the peptide moiety are comparable. Extensive delocalization of unpaired e~(-) density into the peptide moiety triggers isomerizations by proton transfer which are analogous to those in peptide cationradicals lacking change tags. The local recombination energy of Lys ammonium groups decrease with increased H-bonding in the precursor AK or KA cation, as internal solvation is substantially more favorable in charged Lys ammonium than in the corresponding Lys ammonium radicals.