On-line bioaffinity-electrospray mass spectrometry for simultaneous detection, identification, and quantification of protein-ligand interactions

  • Mihaela Dragusanu
  • Brîndusa-Alina Petre
  • Stefan Slamnoiu
  • Camelia Vlad
  • Tingting Tu
  • Michael Przybylski
Focus: Affinity Mass Spectrometry

DOI: 10.1016/j.jasms.2010.06.011

Cite this article as:
Dragusanu, M., Petre, BA., Slamnoiu, S. et al. J Am Soc Mass Spectrom (2010) 21: 1643. doi:10.1016/j.jasms.2010.06.011

Abstract

We describe here an on-line combination of a surface acoustic wave (SAW) biosensor with electrospray ionization mass spectrometry (SAW-ESI-MS) that enables the direct detection, identification, and quantification of affinity-bound ligands from a protein-ligand complex on a biosensor chip. A trapping column was used between the SAW-biosensor and the electrospray mass spectrometer equipped with a micro-guard column, which provides simultaneous sample concentration and desalting for the mass spectrometric analysis of the dissociated ligand. First applications of the on-line SAW-ESI-MS combination include (1), differentiation of β-amyloid (Aβ) epitope peptides bound to anti-Aβ antibodies; (2), the identification of immobilized Substance P peptide-calmodulin complex; (3), identification and quantification of the interaction of 3-nitrotyrosine-modified peptides with nitrotyrosine-specific antibodies; and (4), identification of immobilized anti-α-synuclein-human α-synuclein complex. Quantitative determinations of protein-ligand complexes by SAW yielded dissociation constants (KD) from micro-to low nanomolar sample concentrations. The on-line bioaffinity-ESI-MS combination presented here is expected to enable broad bioanalytical application to the simultaneous, label-free determination and quantification of biopolymer-ligand interactions, as diverse as antigen-antibody and lectin-carbohydrate complexes.

Copyright information

© American Society for Mass Spectrometry 2010

Authors and Affiliations

  • Mihaela Dragusanu
    • 1
  • Brîndusa-Alina Petre
    • 1
  • Stefan Slamnoiu
    • 1
  • Camelia Vlad
    • 1
  • Tingting Tu
    • 2
  • Michael Przybylski
    • 1
  1. 1.Laboratory of Analytical Chemistry and Biopolymer Structure Analysis, Department of ChemistryUniversity of KonstanzKonstanzGermany
  2. 2.Department of ChemistryWashington UniversitySt. LouisUSA

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