Differentiation of peptide isomers and epimers by radical-directed dissociation

TR Lambeth, RR Julian - Methods in Enzymology, 2019 - Elsevier
Isomerization and epimerization are spontaneously occurring modifications that represent
common pathways for age-related damage in proteins. These modifications accumulate …

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules

DL Marshall, CS Hansen, AJ Trevitt, HB Oh… - Physical Chemistry …, 2014 - pubs.rsc.org
Radical-directed dissociation of gas phase ions is emerging as a powerful and
complementary alternative to traditional tandem mass spectrometric techniques for …

Photoinitiated intramolecular diradical cross-linking of polyproline peptides in the gas phase

X Zhang, RR Julian - Physical Chemistry Chemical Physics, 2012 - pubs.rsc.org
Polyproline is a fascinating polymer with interesting structural properties that have been
studied in both solution and the gas phase. Herein, a method capable of measuring …

Differentiation of peptide isomers by excited-state photodissociation and ion–molecule interactions

BL Van Orman, HT Wu, RR Julian - Physical Chemistry Chemical …, 2020 - pubs.rsc.org
Solvochromatic effects are most frequently associated with solution-phase phenomena.
However, in the gas phase, the absence of solvent leads to intramolecular solvation that can …

Exploring radical migration pathways in peptides with positional isomers, deuterium labeling, and molecular dynamics simulations

X Zhang, RR Julian - Journal of The American Society for Mass …, 2013 - ACS Publications
One of the keys for understanding radical directed dissociation in peptides is a detailed
knowledge of the factors that mediate radical migration. Peptide radicals can be created by a …

Comparing positively and negatively charged distonic radical ions in phenylperoxyl forming reactions

PE Williams, DL Marshall, BLJ Poad… - Journal of the …, 2018 - ACS Publications
In the gas phase, arylperoxyl forming reactions play a significant role in low-temperature
combustion and atmospheric processing of volatile organic compounds. We have previously …

Identification of inherently antioxidant regions in proteins with radical-directed dissociation mass spectrometry

OM Hamdy, S Lam, RR Julian - Analytical chemistry, 2014 - ACS Publications
Antioxidant peptides such as glutathione play critically important roles within cells by
opposing the action of oxidative species. Similarly all proteins may, as a secondary function …

Strategies for generating peptide radical cations via ion/ion reactions

JD Gilbert, CM Fisher, J Bu, BM Prentice… - Journal of Mass …, 2015 - Wiley Online Library
Several approaches for the generation of peptide radical cations using ion/ion reactions
coupled with either collision induced dissociation (CID) or ultraviolet photo dissociation …

The innate capacity of proteins to protect against reactive radical species

OM Hamdy, A Alizadeh, RR Julian - Analyst, 2015 - pubs.rsc.org
Maintaining redox homeostasis, or the balance of oxidant and antioxidant forces, is essential
for proper cellular functioning in biology. Although the antioxidant nature of many small …

Leveraging electron transfer dissociation for site selective radical generation: applications for peptide epimer analysis

YA Lyon, G Beran, RR Julian - … of The American Society for Mass …, 2017 - ACS Publications
Traditional electron-transfer dissociation (ETD) experiments operate through a complex
combination of hydrogen abundant and hydrogen deficient fragmentation pathways, yielding …