Detection and structural characterization of natural Ara h 7, the third peanut allergen of the 2S albumin family

J Proteome Res. 2010 Jul 2;9(7):3701-9. doi: 10.1021/pr1002406.

Abstract

In recent years, several novel relevant peanut allergens have been identified. Among those, a new member of the conglutin family was cloned by a phage display approach and initially annotated as Ara h 7.0101. Later, however, recloning of Ara h 7 revealed an alternate isoform, termed Ara h 7.0201. Because the natural Ara h 7 counterpart had not been found at the protein level in peanut extracts, the aim of the present study was to search for authentic natural Ara h 7 protein(s). To this end, enriched low molecular mass proteins (<20 kDa) from peanut extracts were separated by 2D electrophoresis and subjected to mass spectrometric analyses. Fifty of 65 analyzed spots were identified. Interestingly, Ara h 7.0101 was not identified, but Ara h 7.0201 and Ara h 7.0202, a different Ara h 7 isoallergen containing an additional pro-peptide cleavage site, were. In accordance with the conserved cysteine pattern of conglutins, Ara h 7.0201 possesses eight cysteine residues, in contrast to the six cysteines present in the previously cloned Ara h 7.0101. Moreover, a putative cleavage site in the Ara h 7.0202 isoform points to the characteristic biological function of conglutins as amylase/trypsin inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2S Albumins, Plant / chemistry*
  • 2S Albumins, Plant / genetics
  • 2S Albumins, Plant / metabolism
  • Antigens, Plant / chemistry*
  • Antigens, Plant / genetics
  • Antigens, Plant / metabolism
  • Arachis*
  • Base Sequence
  • Electrophoresis, Gel, Two-Dimensional
  • Molecular Sequence Data
  • Plant Extracts / chemistry*
  • Protein Isoforms / chemistry
  • Proteome / chemistry
  • Proteome / genetics
  • Proteome / metabolism
  • Sequence Alignment
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tandem Mass Spectrometry

Substances

  • 2S Albumins, Plant
  • Antigens, Plant
  • Plant Extracts
  • Protein Isoforms
  • Proteome