Tropomyosin, in association with the troponin complex, plays a central role in the calcium dependent regulation of muscle contraction. Homodimer. Expressed in muscle (at protein level). The molecule is in a coiled coil structure that is formed by 2 polypeptide chains. The sequence exhibits a prominent seven-residues periodicity. Causes an allergic reaction in human. Binds to IgE of patients allergic to crustaceans (PubMed:17263503, Ref.3, PubMed:23840718). Heating increases IgE-binding activity. Cross-reacts with blue swimmer crab tropomyosin allergen Por p 1.0101. Recombinant protein causes activation of basophils (PubMed:23840718). Belongs to the tropomyosin family.