Published November 2023 | Version v1

Proteomic insight into allergenic food corona on polyethylene terephthalate microplastics

  • 1. Center of Excellence for Molecular Food Sciences, Department of Biochemistry, University of Belgrade – Faculty of Chemistry, Belgrade, Serbia
  • 2. Department of Chemistry, University of Belgrade – Institute of Chemistry, Technology and Metallurgy, National Institute of Republic of Serbia, Belgrade, Serbia
  • 3. Microprot Lab, Innovation Center of the Faculty of Chemistry, Ltd., Belgrade, Serbia
  • 4. ROR icon Serbian Academy of Sciences and Arts

Description

Microplastics is abundant in the environment, food and beverages and get ingested by humans. Its complex interplay with proteins lead to formation of corona. Tightly bound proteins represent hard corona, while weaker binding partners are found in soft corona. Separation of hard and soft corona of allergenic proteins of shrimps, eggs and cow’s milk, tropomyosin (TPM), ovalbumin (OVA) and beta-lactoglobulin (BLG) and identification of binding partners by proteomics was aim of our study. Allergenic proteins were purified from egg white, shrimps and cow’s milk. Binding to polyethylene terephthalate microplastics (PET) (70-100 m) was probed at pH 7 for purified allergens and egg white proteins. After establishment of binding equilibrium, soft and hard corona were separated and analyzed by SDS PAGE, followed by identification of bound proteins by nanoLC-HRMS. Binding of all allergenic proteins was observed in both soft and hard corona. Soft corona contains exclusively intact, full length OVA, TPM and BLG. Hard corona is enriched for truncated OVA and oligomers of TPM. OVA fragments are partially or fully enfolded and have higher level of exposed hydrophobic patches resulting in higher affinity for PET microplastics. In comparison to OVA and TPM, hard corona of BLG is less abundant under similar conditions. BLG is compact globular protein with lower level of exposed hydrophobic patches in comparison to ovalbumin and tropomyosin. In hard corona, trace amounts of contaminating alfa-lactalbumin become enriched. In the presence of egg white protein extract OVA forms both SC and HC on microplastics, being the dominant protein of hard corona (with ovotransferrin). Lysozyme and ovomucin are present only in hard corona. Both proteins are known for their strong bioactivity and represent a small fraction of total egg white proteins. Our results show that allergenic proteins form hard corona on PET microplastics. Among egg white proteins, minor proteins such as lysozyme and ovomucin become enriched. Denaturing effect of strong binding to microplastics may change functional characteristics of allergens and bioactive proteins of foods and should be further investigated in functional assays.

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Lujic_ItPA-HPS-and-SePA-XVII-International-Congress-2023-abstract-book-.pdf

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Additional details

Funding

European Commission
Imptox - AN INNOVATIVE ANALYTICAL PLATFORM TO INVESTIGATE THE EFFECT AND TOXICITY OF MICRO AND NANO PLASTICS COMBINED WITH ENVIRONMENTAL CONTAMINANTS ON THE RISK OF ALLERGIC DISEASE IN PRECLINICAL AND CLINICAL 965173