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) (PubMed:34255496). Expressed in abdominal muscle (PubMed:27001653). 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. Natural protein binds to IgE in patients allergic to giant fresh water prawn (M.rosenbergii) (PubMed:27001653, PubMed:23569834, PubMed:34255496). Recombinant protein binds to IgE in 77% of the 13 Thai children tested allergic to both seawater prawn P.monodon and freshwater prawn M.rosenbergii. Cross-reacts with P.monodon tropomyosin allergen Pen m 1 (PubMed:27001653). Cross-reacts with tropomyosins of freshwater crustaceans M.lanchesteri, C.quadricarinatus and P.clarkii (PubMed:34255496). Belongs to the tropomyosin family.