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1smg

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CALCIUM-BOUND E41A MUTANT OF THE N-DOMAIN OF CHICKEN TROPONIN C, NMR, 40 STRUCTURES

Structural highlights

1smg is a 1 chain structure with sequence from Gallus gallus. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Solution NMR
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

TNNC2_CHICK 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.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The structural transition in troponin C induced by the binding of two calcium ions involves an "opening" of the structure, an event that triggers skeletal muscle contraction. We have solved the solution structure of a mutant (E41A) of the regulatory domain of skeletal troponin C wherein one bidentate ligand to the calcium in site I is missing. This structure remains "closed" upon calcium binding, indicating that the linkage between calcium binding and the induced conformational change has been broken. This provides a snapshot of skeletal troponin C between the off and on state and thereby valuable insight into the mechanism of regulation within skeletal TnC. Although several factors contribute to the triggering mechanism, the opening of the troponin C structure is ultimately dependent on one amino acid, Glu41. Insights into the structure of cardiac troponin C can also be derived from this skeletal mutant.

Mechanism of direct coupling between binding and induced structural change in regulatory calcium binding proteins.,Gagne SM, Li MX, Sykes BD Biochemistry. 1997 Apr 15;36(15):4386-92. PMID:9109645^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Gagne SM, Li MX, Sykes BD. Mechanism of direct coupling between binding and induced structural change in regulatory calcium binding proteins. Biochemistry. 1997 Apr 15;36(15):4386-92. PMID:9109645 doi:http://dx.doi.org/10.1021/bi963076+