Ion-Induced Dipole Interactions and Fragmentation Times : C$\alpha$ -C$\beta$ Chromophore Bond Dissociation Channel

TL;DR

This study investigates how ion-induced dipole interactions influence fragmentation times in peptides with tryptophan or tyrosine, revealing different dissociation behaviors and times based on the chromophore's nature and postfragmentation interactions.

Contribution

It provides new insights into the role of ion-induced dipole interactions in peptide fragmentation dynamics following photoexcitation.

Findings

Tryptophan peptides show increasing fragmentation times with larger neutral fragments.

Tyrosine peptides exhibit rapid fragmentation times under 20 ns.

Different behaviors are due to postfragmentation interactions in the formed complexes.

Abstract

The fragmentation times corresponding to the loss of the chromophore (C$\alpha$-- C$\beta$ bond dissociation channel) after photoexcitation at 263 nm have been investigated for several small peptides containing tryptophan or tyrosine. For tryptophan-containing peptides, the aromatic chromophore is lost as an ionic fragment (m/z 130), and the fragmentation time increases with the mass of the neutral fragment. In contrast, for tyrosine-containing peptides the aromatic chromophore is always lost as a neutral fragment (mass = 107 amu) and the fragmentation time is found to be fast (\textless{}20 ns). These different behaviors are explained by the role of the postfragmentation interaction in the complex formed after the C$\alpha$--C$\beta$ bond cleavage.