Strawberry protein Fra a 1.02 and birch pollen allergy
What it found
Changing single building blocks of the strawberry protein Fra a 1.02 cut its binding to allergy antibodies from birch pollen allergic patients by 30 to 40 percent in lab tests.
The changed proteins kept their overall shape.
What they found
Studies in people
Antibody binding reduced
In lab tests, all the changed versions of Fra a 1.02 bound 30 to 40 percent less to allergy antibodies from birch pollen allergic patients than the unchanged protein. In inhibition tests, the reduction was between 55 and 80 percent.
Animal and lab studies
Shape stays the same
The authors solved the structures of three of the changed proteins and found that the changes did not affect the overall fold. The mutated amino acids could be confirmed in the structures.
Loop 5 and antibody binding
A change at position 64, in the flexible loop 5, also reduced antibody binding. The authors suggest this loop may play a role in how the protein is recognised by allergy antibodies.
Studies in people and animals
Key areas for antibodies
Changes in the 42 to 52 region and at position 141 gave the lowest antibody binding. The authors say these areas are likely important for how allergy antibodies recognise the protein.
Other findings
Structure of the protein
The authors worked out the three-dimensional shape of Fra a 1.02 at 2.04 Å resolution. It has the same overall fold as other PR-10 proteins, with a large internal cavity that can be reached through three openings.
What the authors conclude
“The strategy followed herein has allowed the generation of new isoforms of Fra a 1.02 that retain their overall fold and display a lower IgE-binding capacity.”
Also in their conclusions
- They say their strategy produced new versions of Fra a 1.02 that keep their overall shape but bind less to allergy antibodies.
- They suggest that with further work to lower antibody binding even more, these changed proteins could be tested as vaccines against strawberry allergy.
- They note that a similar approach worked for the birch pollen allergen Bet v 1, where changed proteins stimulated T cells and induced antibodies that blocked IgE binding.
How it was done
Strawberry allergy in Central and Northern Europe is mainly caused by Fra a 1.02, a protein in ripe fruit that is similar to the birch pollen allergen Bet v 1. The authors wanted to find which parts of this protein the allergy antibodies recognise, so they could design versions with lower allergenic potential for future treatments.
The authors worked out the three-dimensional structure of Fra a 1.02 and made five changed versions of it. They then tested how well each version bound to allergy antibodies in blood serum pooled from 20 patients allergic to birch pollen.
What it can’t tell you
- The antibody tests used blood serum in the lab, not people eating strawberries, so they cannot show what symptoms these changed proteins would cause.
- The authors say further studies are needed before these changed proteins could be tested as vaccines.
Who paid
- Funding
- Funded by Medical Research Council (from the PubMed record).
- Conflicts
- The authors declare no competing financial interest.
- Authors work at
- Instituto de Hortofruticultura Subtropical y Mediterránea (IHSM), Spain; European Molecular Biology Laboratory, France; International Institute of Molecular and Cell Biology, Poland
The paper
- Title
- Structural Bases for the Allergenicity of Fra a 1.02 in Strawberry Fruits
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Orozco-Navarrete B, Kaczmarska Z, Dupeux F, et al (2020). Structural Bases for the Allergenicity of Fra a 1.02 in Strawberry Fruits. Journal of agricultural and food chemistry. doi:10.1021/acs.jafc.9b05714Free full textPubMed 31774998DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error