• The first report and identification of "Sarcoplasmic calcium-binding protein allergen" in the edible blue swimmer crab from Persian Gulf
  • Rezvan Mousavi-Nadushan,1,* Naghmeh Roohi-Shalmaee,2 Khadigeh Rezaiy,3
    1. Department of Marine Science, Faculty of Natural Resources and Environment, Tehran North Branch, Islamic Azad University Tehran, Iran.
    2. Venom and Biotherapeutics Molecules Lab., Biotechnology Dept., Biotechnology Research Center, Pasteur Institute of Iran. Tehran, Iran.
    3. Department of food science and technology, North Tehran Branch, Islamic Azad University, Tehran, Iran


  • Introduction: Food allergy can result in mild to life-threatening reaction known as anaphylaxis, subsequently food allergens are considered as a public health problem. There is no therapeutic treatment for food allergy, so disease may only be coped by allergen avoidance or treatment of signs. The European Food Safety Authority (EFSA) established the necessity of developing new methodologies for food allergen identification and labelling the allergenic products. Accordingly, Seafood products is increasingly important as a worldwide main protein source. Sarcoplasmic Ca 2+ -binding proteins (SCPs) belong to the family of EF-hand calcium-binding proteins which are abundant in the muscle of crustaceans. Sarcoplasmic Ca 2+ -binding proteins is an allergen recognized by serum IgE in 38% of patients with shrimp/crustacean allergy. Similar to other allergenic constituents, sarcoplasmic Ca 2+ -binding proteins are highly conserved among crustaceans. There remains a strong necessity to compile a comprehensive shellfish allergen investigation/identification. In this research, we aim to introduce one of the important allergens that we defined in edible blue swimmer crab of Persian Gulf by proteomics and bioinformatics.
  • Methods: Extraction: Raw crab muscle, were mixed with distilled water and manually homogenized in a mortar. Then the Extract were lyophilized and stored at –20°C. MALDI-TOF analyses: the proteins bands at 17 KD on SDS-PAGE gel were selected for MALDI-TOF analyses. Matrix-assisted laser desorption/ionization mass spectrometry (Applied Biosystems 4800 MALDI TOF/TOF, Nd:YAG 200-HZ laser) was used for MS experiments. Bioinformatics analyses: The homology of peptide fragments, obtained from MALDI-TOF, was controlled against NCBI and UniProt databanks using blastP and their functions and molecular roles were investigated in different servers.
  • Results: A 17 kDa protein was purified from blue swimmer crab from Persian Gulf, and BlastP analysis of the peptide fragments showed homology with Sarcoplasmic calcium-binding protein (SCP_SCYPA) as well.
  • Conclusion: Some proteins from crustaceans are responsible for induction of allergic reactions in both children and adults. Subsequent MALDI-TOF analysis of a 17-KD protein from a SDS-PAGE gel yielded the sequence of multiple peptides recognized as belonging to a sarcoplasmic Ca2+ binding protein. Bioinformatics analyses hit the codes for the protein sequence of Sarcoplasmic calcium-binding protein (SCP_SCYPA) as (I2DDG2 • SCP_SCYPA) in Scylla paramamosain (Mud crab) in uniprot servers. Gene ontology analyses showed that this protein has a main role in the calcium ion binding (GO: 0005509). Also another molecular function of SCPs is protein homodimerization activity in which proteins interact, homo- or hetero-dimers, to produce a functional assemblage (GO: 0042803). Moreover, a diverse intensity of cross-reactivity and sequence homology were verified among crustacean species. Consequently, an additional extensive study of crustacean allergy should be explored. Accordingly, for the first time, we detect sarcoplasmic calcium-binding protein in the mussel of edible blue swimmer crab from Persian Gulf.
  • Keywords: Blue swimmer crab; Persian Gulf; Proteomics; Bioinformatics; Allergen.