Tropomyosin, in association with the troponin complex, plays a central role in the calcium dependent regulation of muscle contraction. Homodimer. Muscle (at protein level) (Ref.1, PubMed:20564455). Expressed in leg and chest protection muscle (at protein level) (PubMed:20564455). Expressed in claw muscle (Ref.1). 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 (Ref.1, PubMed:20564455). Binds to IgE in 100% of the 21 patients tested allergic to crustaceans (Ref.1). Allergenicity of this protein is reduced by pepsin or chymotrypsin, and most effectively by trypsin, digestion in vitro (PubMed:20564455). Belongs to the tropomyosin family.