Protein Chemistry: Structure, Properties, and Research Methods - Shendryk, A.N. 2022

Proteins of the Blood and Muscle Tissues
Proteins of the Contractile System
Functions of Muscle Tissue Proteins: Tropomyosin A, B

Tropomyosin A and tropomyosin B are Fibrillar Proteins of Muscle tissue. Tropomyosin B is Water-soluble and found in all Muscles. It is an essential component of the thin filaments that make up the I-band. Tropomyosin A (or paramyosin) is a water-insoluble form of tropomyosin, discovered in the catch muscle of Mollusks.

The tropomyosin B molecule is rod-shaped, approximately 450Å in length and 20Å in diameter, with a Molecular Weight of ≅ 130 kDa. It consists of two highly similar peptide chains with a molecular weight of about 70 kDa. Both chains adopt an α-helical conformation and coil around each other to form a superhelix, similar to the Myosin superhelix. Free SH-groups are present in both chains.

Mixing tropomyosin B with F-Actin results in The formation of a complex. It is hypothesized that within this complex, the tropomyosin B molecule lies within the groove of the double-stranded F-actin superhelix.



Last update: 06/08/2026

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