Isotopically labeled crosslinking reagents: Resolution of mass degeneracy in the identification of crosslinked peptides

Christopher J. Collins, Birgit Schilling, Malin Young, Gavin Dollinger, R. Kiplin Guy

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Mass spectrometry in three dimensions (MS3D) is a newly developed method for the determination of protein structures involving intramolecular chemical crosslinking of proteins, proteolytic digestion of the resulting adducts, identification of crosslinks by mass spectrometry (MS), peak assignment using theoretical mass lists, and computational reduction of crosslinks to a structure by distance geometry methods. To facilitate the unambiguous identification of crosslinked peptides from proteolytic digestion mixtures of crosslinked proteins by MS, we introduced double 18O isotopic labels into the crosslinking reagent to provide the crosslinked peptides with a characteristic isotope pattern. The presence of doublets separated by 4 Da in the mass spectra of these materials allowed ready discrimination between crosslinked and modified peptides, and uncrosslinked peptides using automated intelligent data acquisition (IDA) of MS/MS data. This should allow ready automation of the method for application to whole expressible proteomes.

Original languageEnglish
Pages (from-to)4023-4026
Number of pages4
JournalBioorganic and Medicinal Chemistry Letters
Issue number22
StatePublished - Nov 17 2003

Bibliographical note

Funding Information:
The Sandler Research Foundation, NSF (CHE-0118481), and UC BIOSTAR grant (S98-63, UCSF and Chiron Corporation) supported this project and NIH Postdoctoral Training Grant T35 CA 09270 provided stipend support for Dr. Collins.

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmaceutical Science
  • Drug Discovery
  • Clinical Biochemistry
  • Organic Chemistry


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