title: Identification of triosephosphate isomerase as a novel allergen in Octopus fangsiao.
abstract: Octopus is an important mollusk in human dietary for its nutritional value, however it also causes allergic reactions in humans. Major allergens from octopus have been identified, while the knowledge of novel allergens remains poor. In the present study, a novel allergen with molecular weight of 28kDa protein was purified from octopus (Octopus fangsiao) and identified as triosephosphate isomerase (TIM) by mass spectrometry. TIM aggregated beyond 45°C, and its IgE-binding activity was affected under extreme pH conditions due to the altered secondary structure. In simulated gastric fluid digestion, TIM can be degraded into small fragments, while retaining over 80% of the IgE-binding activity. The full-length cDNA of O. fangsiao TIM (1140bp) was cloned, which encodes 247 amino acid residues, and the entire recombinant TIM was successfully expressed in Escherichia coli BL21, which showed similar immunoreactivity to the native TIM. Different intensity of cross-reactivity among TIM from related species revealed the complexity of its epitopes. Eight linear epitopes of TIM were predicted following bioinformatic analysis. Furthermore, a conformational epitope (A71G74S69D75T73F72V67) was confirmed by the phage display technology. The results revealed the physicochemical and immunological characteristics of TIM, which is significant in the development of hyposensitivity food and allergy diagnosis.
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Zhong-Wei
authors.initials: ZW
authors.lastname: Chen
authors.affiliation: U.S. Department of Agriculture, Agriculture Research Service, Southern Regional Research Center, 1100 Robert E. Lee Boulevard, New Orleans, LA, 70124, USA.
authors.forename: Barry K
authors.initials: BK
authors.lastname: Hurlburt
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Gui-Ling
authors.initials: GL
authors.lastname: Li
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Yong-Xia
authors.initials: YX
authors.lastname: Zhang
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Dan-Xia
authors.initials: DX
authors.lastname: Fei
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Hai-Wang
authors.initials: HW
authors.lastname: Shen
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China.
authors.forename: Min-Jie
authors.initials: MJ
authors.lastname: Cao
authors.affiliation: College of Food and Biological Engineering, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Xiamen Key Laboratory of Marine Functional Food, Jimei University, 43 Yindou Road, Xiamen, Fujian, 361021, China. Electronic address: gmliu@jmu.edu.cn.
authors.forename: Guang-Ming
authors.initials: GM
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D002648:Child; D003001:Cloning, Molecular; D003429:Cross Reactions; D015180:Electrophoresis, Gel, Two-Dimensional; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D005260:Female; D005512:Food Hypersensitivity / Q000209:etiology / Q000276:immunology; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D049831:Octopodiformes / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000276:immunology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014305:Triose-Phosphate Isomerase / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D055815:Young Adult
chemical_list: D000485:Allergens; D018985:Epitopes, B-Lymphocyte; D014305:Triose-Phosphate Isomerase
keywords: Allergen; Epitope analysis; Octopus fangsiao; Physicochemical characterization; Purification; Triosephosphate isomerase