MALDI/post ionization-ion mobility mass spectrometry of noncovalent complexes of dopamine receptors' epitopes

Amina S. Woods, Shelley N. Jackson, Ernest K. Lewis, Thomas Egan, Ludovic Muller, Jean Claude Tabet, J. Albert Schultz

Research output: Contribution to journalArticlepeer-review

Abstract

Protein domains involved in receptor heteromer formation are disordered and rich in the amino acids necessary for the formation of noncovalent complexes (NCX). We present mass spectral NCX data from proteins and protein receptors' epitopes obtained by combining ion mobility (IM) and MALDI. We focus on NCX involved in heteromer formation occurring between epitopes of the Dopamine D2 (D2R) and Adenosine A2A receptors (A 2AR) as well as D2R and the α2 nicotinic (NR) receptor's subunit. The IM data yield information on the gas phase conformation of the singly charged NCX which are observed either directly from MALDI or as codesorbed neutrals that are subsequently postionized by a time-delayed excimer laser pulse directed onto a portion of the neutral plume created by the MALDI desorption laser. Imaging mass spectrometry of the matrix/epitope dried droplet surface shows that the acidic and basic epitopes and their NCX are found to be spatially collocated within regions as small as 25 × 50 μm2. Subtle differences in the relative abundance of protonated and cationized NCX and epitopes are measured in spatial regions near the sodium-rich outer border of the droplet.

Original languageEnglish (US)
Pages (from-to)1668-1677
Number of pages10
JournalJournal of Proteome Research
Volume12
Issue number4
DOIs
StatePublished - Apr 5 2013
Externally publishedYes

Keywords

  • disordered proteins
  • dopamine receptor
  • heteromers
  • ion-mobility
  • noncovalent interactions

ASJC Scopus subject areas

  • Biochemistry
  • Chemistry(all)

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