Establishing Signature Fragments for Identification and Sequencing of Dityrosine Cross-Linked Peptides Using Ultraviolet Photodissociation Mass Spectrometry

Soumya Mukherjee; Mengxuan Fang; W Mei Kok; Eugene A Kapp; Varsha J Thombare; Romain Huguet; Craig A Hutton; Gavin E Reid; Blaine R Roberts

doi:10.1021/acs.analchem.9b02986

Establishing Signature Fragments for Identification and Sequencing of Dityrosine Cross-Linked Peptides Using Ultraviolet Photodissociation Mass Spectrometry

Anal Chem. 2019 Oct 1;91(19):12129-12133. doi: 10.1021/acs.analchem.9b02986. Epub 2019 Sep 11.

Authors

Soumya Mukherjee¹, Mengxuan Fang², W Mei Kok³, Eugene A Kapp¹, Varsha J Thombare², Romain Huguet⁴, Craig A Hutton², Gavin E Reid^{2

5}, Blaine R Roberts¹

Affiliations

¹ Florey Institute of Neuroscience and Mental Health , University of Melbourne , Melbourne , Victoria 3010 , Australia.
² School of Chemistry, Bio21 Molecular Science and Biotechnology Institute , The University of Melbourne , Parkville , 3010 , Australia.
³ University of Queensland , Institute for Molecular Bioscience , Brisbane , Queensland 4072 , Australia.
⁴ Thermo Fisher Scientific , San Jose , California 95134 , United States.
⁵ Department of Biochemistry and Molecular Biology , The University of Melbourne , Parkville , Victoria 3010 , Australia.

PMID: 31490671
DOI: 10.1021/acs.analchem.9b02986

Abstract

Dityrosine cross-linking of Aβ peptides and α-synuclein is increasingly becoming recognized as a biomarker of neuropathological diseases. However, there remains a need for the development of analytical methods that enable the specific and selective identification of dityrosine cross-linked proteins and peptides in complex biological samples. Here, we report that the gas-phase fragmentation of protonated dityrosine cross-linked peptides under ultraviolet photodissociation (UVPD) tandem mass spectrometry (MS/MS) conditions results in the cleavage across C_α and C_β atoms of the dityrosine residue. This C_α-C_β cleavage in UVPD-MS/MS results in the formation of diagnostic pairs of product ions, providing information on the two individual peptides involved in the cross-linking, resolving the intrinsic "n² problem" plaguing the identification of this post-translational modification (PTM) by tandem mass spectrometry. Sequencing of a heterodimeric dityrosine cross-linked peptide was demonstrated using hybrid UVPD-MS/MS and CID-MS³ on a diagnostic pair of product ions. In combination with dedicated MS-cleavable MSⁿ software, UVPD-MSⁿ therefore provides an avenue to selectively discover and describe dityrosine cross-linked peptides. Additionally, observation of dityrosine-specific "reporter ions" at m/z 240.1019 and m/z 223.0752 in UVPD-MS/MS will be useful for the validation of the dityrosine cross-linked peptides.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amyloid beta-Peptides / analysis
Amyloid beta-Peptides / chemistry
Amyloid beta-Peptides / metabolism
Peptide Fragments / analysis
Peptide Fragments / chemistry
Peptide Fragments / metabolism
Peptides / analysis
Peptides / chemistry*
Peptides / metabolism
Photochemical Processes
Protein Processing, Post-Translational
Sequence Analysis, Protein
Tandem Mass Spectrometry / methods*
Tyrosine / analogs & derivatives*
Tyrosine / chemistry
Ultraviolet Rays

Substances

Amyloid beta-Peptides
Peptide Fragments
Peptides
amyloid beta-protein (1-16)
Tyrosine
dityrosine