Discriminating d-Amino Acid-Containing Peptide
Epimers by Radical-Directed Dissociation Mass Spectrometry
Yuanqi Tao
Neil R. Quebbemann
Ryan R. Julian
10.1021/ac3013434.s001
https://acs.figshare.com/articles/journal_contribution/Discriminating_d_Amino_Acid_Containing_Peptide_Epimers_by_Radical_Directed_Dissociation_Mass_Spectrometry/2498446
The presence of a single d-amino acid in a peptide
is
very difficult to detect. Mass spectrometry-based approaches rely
on differences in fragmentation between all l-amino acid-containing
peptides and single d-amino acid-containing peptides (which
are epimers) for identification. The success of this approach is dependent
on the structural sensitivity of the fragmentation method. Recently,
experiments have demonstrated that fragmentation initiated by radical
chemistry, or radical-directed dissociation (RDD), is particularly
sensitive to the structure of the ion being fragmented. Herein, RDD
is used to identify the presence of d-serine, d-alanine,
or d-aspartic acid in eight biologically relevant peptides.
It is demonstrated that chiral disambiguation by RDD is dependent
on both the initial radical site and subsequent radical migration.
Fortuitously, RDD can be initiated by a variety of different radical
precursors which can be associated with the peptide via covalent or
noncovalent means, and RDD can be examined in all observable charge
states (both positive and negative). This diversity enables numerous
initial radical sites and migration pathways to be explored. For all
but one of the peptides that were examined, RDD provides significantly
better chiral discrimination than CID. Quantitation of peptide epimers
by RDD is also described.
2012-08-07 00:00:00
chiral disambiguation
peptide epimers
charge states
CID
RDD
migration pathways
fragmentation method
chiral discrimination