Comparative analysis of barnacle tropomyosin: divergence from decapod tropomyosins and role as a potential allergen.
Tropomyosin, a myofibrillar protein of 35-38 kDa, represents a major and cross-reactive allergen in decapod crustaceans. This study was initiated to clarify whether decapod-allergic patients also recognize tropomyosins of barnacles, crustaceans phylogenetically remote from decapods, which are locally consumed as a delicacy. On SDS-PAGE, a 37 kDa protein was observed in all the heated extracts prepared from two species of decapods (American lobster Homarus americanus and black tiger prawn Penaeus monodon) and two species of barnacles (acorn barnacle Balanus rostratus and goose barnacle Capitulum mitella). In immunoblotting, the 37 kDa protein was found to react with monoclonal antibodies against American lobster tropomyosin and hence identified as tropomyosin. The patient sera reacted to tropomyosins from both decapods and barnacles and the reactivity was abolished by preincubation with American lobster tropomyosin, demonstrating that barnacle tropomyosins are allergens cross-reactive with decapod tropomyosins. However, the amino acid sequence of acorn barnacle tropomyosin, deduced by cDNA cloning experiments, shares higher sequence identity with abalone tropomyosins than with decapod tropomyosins. In accordance with this, the phylogenetic tree made for tropomyosins from various animals showed that the acorn barnacle tropomyosin is evolutionally classified not into the decapod tropomyosin family but into the molluscan tropomyosin family.
Suma
Yota
Y
Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Konan-4, Tokyo 108-8477, Japan.
Ishizaki
Shoichiro
S
Nagashima
Yuji
Y
Lu
Ying
Y
Ushio
Hideki
H
Shiomi
Kazuo
K
D000485:Allergens / Q000097:blood* / Q000276:immunology; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D016000:Cluster Analysis; D018076:DNA, Complementary / Q000235:genetics; D033364:Decapoda / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D001468:Thoracica / Q000235:genetics*; D014335:Tropomyosin / Q000235:genetics* / Q000276:immunology*
D000485:Allergens; D018076:DNA, Complementary; D014335:Tropomyosin