Mass spectrometry-based thermal shift assay for protein-ligand binding analysis.

Journal Article

Described here is a mass spectrometry-based screening assay for the detection of protein-ligand binding interactions in multicomponent protein mixtures. The assay utilizes an oxidation labeling protocol that involves using hydrogen peroxide to selectively oxidize methionine residues in proteins in order to probe the solvent accessibility of these residues as a function of temperature. The extent to which methionine residues in a protein are oxidized after specified reaction times at a range of temperatures is determined in a MALDI analysis of the intact proteins and/or an LC-MS analysis of tryptic peptide fragments generated after the oxidation reaction is quenched. Ultimately, the mass spectral data is used to construct thermal denaturation curves for the detected proteins. In this proof-of-principle work, the protocol is applied to a four-protein model mixture comprised of ubiquitin, ribonuclease A (RNaseA), cyclophilin A (CypA), and bovine carbonic anhydrase II (BCAII). The new protocol's ability to detect protein-ligand binding interactions by comparing thermal denaturation data obtained in the absence and in the presence of ligand is demonstrated using cyclosporin A (CsA) as a test ligand. The known binding interaction between CsA and CypA was detected using both the MALDI- and LC-MS-based readouts described here.

Full Text

Duke Authors

Cited Authors

  • West, GM; Thompson, JW; Soderblom, EJ; Dubois, LG; Dearmond, PD; Moseley, MA; Fitzgerald, MC

Published Date

  • July 1, 2010

Published In

Volume / Issue

  • 82 / 13

Start / End Page

  • 5573 - 5581

PubMed ID

  • 20527820

Electronic International Standard Serial Number (EISSN)

  • 1520-6882

Digital Object Identifier (DOI)

  • 10.1021/ac100465a

Language

  • eng

Conference Location

  • United States