Enzymatic activity and immunoreactivity of Aca s 4, an alpha-amylase allergen from the storage mite Acarus siro

BMC Biochem. 2012 Jan 31;13:3. doi: 10.1186/1471-2091-13-3.

Abstract

Background: Enzymatic allergens of storage mites that contaminate stored food products are poorly characterized. We describe biochemical and immunological properties of the native alpha-amylase allergen Aca s 4 from Acarus siro, a medically important storage mite.

Results: A. siro produced a high level of alpha-amylase activity attributed to Aca s 4. This enzyme was purified and identified by protein sequencing and LC-MS/MS analysis. Aca s 4 showed a distinct inhibition pattern and an unusual alpha-amylolytic activity with low sensitivity to activation by chloride ions. Homology modeling of Aca s 4 revealed a structural change in the chloride-binding site that may account for this activation pattern. Aca s 4 was recognized by IgE from house dust mite-sensitive patients, and potential epitopes for cross-reactivity with house dust mite group 4 allergens were found.

Conclusions: We present the first protein-level characterization of a group 4 allergen from storage mites. Due to its high production and IgE reactivity, Aca s 4 is potentially relevant to allergic hypersensitivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acaridae / enzymology*
  • Acaridae / immunology
  • Allergens / chemistry*
  • Allergens / immunology
  • Allergens / isolation & purification
  • Amino Acid Sequence
  • Animals
  • Cross Reactions
  • Feces / chemistry
  • Humans
  • Hypersensitivity / blood
  • Hypersensitivity / immunology
  • Immunoglobulin E / blood
  • Insect Proteins / chemistry*
  • Insect Proteins / immunology
  • Insect Proteins / isolation & purification
  • Molecular Sequence Data
  • Protein Binding
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Structural Homology, Protein
  • alpha-Amylases / chemistry*
  • alpha-Amylases / immunology
  • alpha-Amylases / isolation & purification

Substances

  • Allergens
  • Insect Proteins
  • Immunoglobulin E
  • alpha-Amylases