Using ion mobility spectrometry to resolve isotopomers, identify isomers by isotopologic shifts, and predict mobility changes for post-translationally modified peptides
Date
2017-05Author
Kaszycki, Julia L.
Advisor
Shvartsburg, Alexandre A.Metadata
Show full item recordAbstract
Differential or field asymmetric waveform ion mobility spectrometry (FAIMS)
operating at high electric fields fully resolves isotopic isomers for a peptide with labeled
residues. The naturally present isotopes, alone and together with targeted labels, also cause
spectral shifts that approximately add for multiple heavy atoms. Separation qualitatively
depends on the gas composition and field strength. These findings may enable novel strategies
in proteomic and metabolomic analyses using stable isotope labeling.
FAIMS delves more deeply into the naturally present isotopes and shows a method for
characterization of isomers based upon their isotopologic shifts in a high electric field. It looks
at the differentiating +1 Da shifts for identification with monohalogenated anilines. This
produces an identifying fingerprint potentially for any ion based on isotopologic shifts.
The rising profile of ion mobility spectrometry (IMS) in proteomics has driven the efforts
to predict peptide cross-sections. In the simplest approach, these are derived by adding the
contributions of all amino acid residues and post-translational modifications (PTMs) defined by
their intrinsic size parameters (ISPs). It shows that the ISPs for PTMs can be calculated from
properties of constituent atoms, and introduce the "impact scores" that govern the shift of crosssections
from the central mass-dependent trend for unmodified peptides. The ISPs and scores
tabulated for 100 more common PTMs enable predicting the domains for modified peptides in
the IMS/MS space that would guide subproteome investigations.
Description
Thesis (M.S.)--Wichita State University, Fairmount College of Liberal Arts and Sciences, Dept. of Chemistry