Targeted Mass Spectrometry-Based Approach for Protein-Ligand Binding Analyses in Complex Biological Mixtures Using a Phenacyl Bromide Modification Strategy

Anal Chem. 2016 Nov 15;88(22):10987-10993. doi: 10.1021/acs.analchem.6b02658. Epub 2016 Oct 26.

Abstract

The characterization of protein folding stability changes on the proteomic scale is useful for protein-target discovery and for the characterization of biological states. The Stability of Proteins from Rates of Oxidation (SPROX) technique is one of several mass spectrometry-based techniques recently established for the making proteome-wide measurements of protein folding and stability. A critical part of proteome-wide applications of SPROX is the identification and quantitation of methionine-containing peptides. Demonstrated here is a targeted mass spectrometry-based proteomics strategy for the detection and quantitation of methionine-containing peptides in SPROX experiments. The strategy involves the use of phenacyl bromide (PAB) for the targeted detection and quantitation of methionine-containing peptides in SPROX using selective reaction monitoring (SRM) on a triple quadrupole mass spectrometer (QQQ-MS). As proof-of-principle, the known binding interaction of Cyclosporine A with cyclophilin A protein in a yeast cell lysate is successfully detected and quantified using a targeted SRM workflow. Advantages of the described workflow over other SPROX protocols include a 20-fold reduction in the amount of total protein needed for analysis and the ability to work with the endogenous proteins in a given sample (e.g., stabile isotope labeling with amino acids in cell culture is not necessary).

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetophenones / chemistry*
  • Binding Sites
  • Ligands*
  • Mass Spectrometry*
  • Oxidation-Reduction
  • Peptides / chemistry
  • Protein Folding
  • Proteins / chemistry*

Substances

  • Acetophenones
  • Ligands
  • Peptides
  • Proteins
  • phenacyl bromide