Tropomyosin, in association with the troponin complex, plays a central role in the calcium dependent regulation of muscle contraction. Homodimer. 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 atopic shrimp-allergic patients (PubMed:16339577, PubMed:16630158, PubMed:11893851). Binds to IgE in 100% of the 18 patients tested (PubMed:11893851). Causes release of beta-hexosaminidase from wild-type and humanized rat basophil leukemia (RBL) cells (PubMed:16339577, PubMed:16630158). Constructed epitope mutant has significantly reduced allergenic potency, and hence could represent a candidate vaccine for treatment of shrimp food allergy. Belongs to the tropomyosin family.