Cloning, Expression, and the Effects of Processing on Sarcoplasmic-Calcium-Binding Protein: An Important Allergen in Mud Crab.
Shellfish allergy is a prevalent, long-lasting disorder usually persisting throughout life. However, the allergen information is incomprehensive in crab. This study aimed to identify a novel allergen in crab, show its potential in diagnosis and reduce the allergenicity by food processing. A 21-kDa protein was purified from Scylla paramamosain and confirmed as sarcoplasmic calcium binding protein (SCP) by matrix-assisted laser desorption ionization-time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). Total RNA was isolated from crab muscle, and a rapid amplification of cDNA was performed to obtain an ORF of 579 bp that coded for 193 amino acid residues. According to the results of circular dichroism analysis and ELISA assay, the recombinant SCP (rSCP) expressed in Escherichia coli showed similar physicochemical and immunoreactive properties to native SCP (nSCP). Additionally, the extensive cross reactivity of SCP among different species and the bidirectional IgE cross-reactivity between nSCP and rSCP were detected by iELISA. The allergenicity of rSCP was reduced via Maillard reaction or enzymatic cross-linking reaction, which was confirmed by the results of scanning electron microscopy, dot blot, and digestion assay. A straightforward and reproducible way was developed to obtain high yields of rSCP that maintains structural integrity and full IgE reactivity, which could compensate the low specific IgE-titers of most patient sera for future diagnosis. Furthermore, the Maillard reaction and enzymatic cross-linking reaction were effective approaches for the production of hypoallergenic seafood.
['Hu|Meng-Jun|MJ|', 'Liu|Guang-Yu|GY|', 'Yang|Yang|Y|', 'Pan|Tzu-Ming|TM|http://orcid.org/0000-0002-9865-1893', 'Liu|Yi-Xiang|YX|http://orcid.org/0000-0002-4574-8309', 'Sun|Le-Chang|LC|', 'Cao|Min-Jie|MJ|', 'Liu|Guang-Ming|GM|http://orcid.org/0000-0002-8689-0504']
D000485:Allergens D000595:Amino Acid Sequence D000818:Animals D003386:Brachyura D002135:Calcium-Binding Proteins D003001:Cloning, Molecular D006801:Humans D007073:Immunoglobulin E D008969:Molecular Sequence Data D012519:Sarcoplasmic Reticulum D016415:Sequence Alignment D012758:Shellfish D000067208:Shellfish Hypersensitivity
expression diagnosis Scylla paramamosain sarcoplasmic calcium binding protein allergenicity reducing