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Collisional Dynamics Simulations Revealing Fragmentation Properties of Zn(II)-Bound Poly-Peptide

preprint
submitted on 30.04.2020 and posted on 04.05.2020 by Abdul Malik, Laurence A. Angel, Riccardo Spezia, William L. Hase

Chemical dynamics simulations are performed to study the collision induced gas phase unimolecular fragmentation of a model peptide with the sequence acetyl-His1-Cys2-Gly3-Pro4-Tyr5-His6-Cys7 (analogue methanobactin peptide-5, amb5) and in particular to explore the role of zinc binding on reactivity. Fragmentation pathways, their mechanisms, and collision energy transfer are discussed. The probability distributions of the pathways are compared with the results of the experimental IM-MS, MS/MS spectrum and previous thermal simulations. Collisional activation gives both statistical and non-statistical fragmentation pathways with non-statistical shattering mechanisms accounting for a relevant percentage of reactive trajectories, becoming dominant at higher energies. The tetra-coordination of zinc changes qualitative and quantitative fragmentation, in particular the shattering. The collision energy threshold for the shattering mechanism was found to be 118.9 kcal/mol which is substantially higher than the statistical Arrhenius activation barrier of 35.8 kcal/mol identified previously during thermal simulations. This difference can be attributed to the tetra-coordinated zinc complex that hinders the availability of the sidechains to undergo direct collision with the Ar projectile.

Funding

Welch Foundation

National Science Foundation

History

Email Address of Submitting Author

riccardo.spezia@sorbonne-universite.fr

Institution

Sorbonne Université, Laboratoire de Chimie Théorique

Country

France

ORCID For Submitting Author

0000-0001-5160-489X

Declaration of Conflict of Interest

No conflict of interest

Version Notes

First submission

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