Jug r 4, a legumin group food allergen from walnut (Juglans regia Cv. Chandler)

J Agric Food Chem. 2006 Oct 18;54(21):8369-75. doi: 10.1021/jf061329s.


Allergy to walnut is the most frequently reported tree nut allergy in the United States. Walnut 2S albumin, a vicilin-like protein, and a lipid transfer protein allergen have previously been described. Our objective was to clone and express a cDNA encoding a legumin group protein, assess IgE-binding with sera from walnut allergic patients, and investigate cross-reactivity with selected nuts. Primers were used to obtain the cDNA by 5' and 3' rapid amplification of cDNA ends from walnut mRNA. The cDNA was subcloned into the pMAL-c2X vector and the recombinant fusion protein, named rJug r 4, was expressed in Escherichia coli. The obtained cDNA encoded a precursor protein with a predicted molecular weight of 58.1 kD, which showed significant sequence homology to hazelnut and cashew legumin allergens. Serum IgE from 21 of 37 (57%) patients bound the rJug r 4 fusion protein. In vitro cross-reactivity was demonstrated with hazelnut, cashew, and peanut protein extracts.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allergens / genetics*
  • Amino Acid Sequence
  • Antibody Specificity
  • Antigens, Plant / chemistry
  • Antigens, Plant / genetics*
  • Antigens, Plant / immunology*
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • Escherichia coli
  • Food Hypersensitivity / immunology
  • Gene Expression
  • Humans
  • Immunoblotting
  • Immunoglobulin E / blood
  • Juglans / immunology*
  • Legumins
  • Molecular Sequence Data
  • Plant Proteins / immunology*
  • Protein Precursors
  • Recombinant Fusion Proteins / immunology
  • Sequence Alignment


  • Allergens
  • Antigens, Plant
  • DNA, Complementary
  • Jug r 4 allergen
  • Plant Proteins
  • Protein Precursors
  • Recombinant Fusion Proteins
  • Immunoglobulin E