Structural highlights
Function
[TNNC2_HUMAN] Troponin is the central regulatory protein of striated muscle contraction. Tn consists of three components: Tn-I which is the inhibitor of actomyosin ATPase, Tn-T which contains the binding site for tropomyosin and Tn-C. The binding of calcium to Tn-C abolishes the inhibitory action of Tn on actin filaments.
Publication Abstract from PubMed
Troponin regulates the calcium-mediated activation of skeletal muscle. Muscle weakness in diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy occurs from diminished neuromuscular output. The first direct fast skeletal troponin activator, tirasemtiv, amplifies the response of muscle to neuromuscular input. Tirasemtiv binds selectively and strongly to fast skeletal troponin, slowing the rate of calcium release and sensitizing muscle to calcium. We report the solution NMR structure of tirasemtiv bound to a fast skeletal troponin C-troponin I chimera. The structure reveals that tirasemtiv binds in a hydrophobic pocket between the regulatory domain of troponin C and the switch region of troponin I, which overlaps with that of Anapoe in the X-ray structure of skeletal troponin. Multiple interactions stabilize the troponin C-troponin I interface, increase the affinity of troponin C for the switch region of fast skeletal troponin I, and drive the equilibrium toward the active state.
Structural Basis of Tirasemtiv Activation of Fast Skeletal Muscle.,Li MX, Mercier P, Hartman JJ, Sykes BD J Med Chem. 2021 Mar 11. doi: 10.1021/acs.jmedchem.0c01412. PMID:33703886[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Li MX, Mercier P, Hartman JJ, Sykes BD. Structural Basis of Tirasemtiv Activation of Fast Skeletal Muscle. J Med Chem. 2021 Mar 11. doi: 10.1021/acs.jmedchem.0c01412. PMID:33703886 doi:http://dx.doi.org/10.1021/acs.jmedchem.0c01412
