| Structural highlights
3sd6 is a 1 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , |
| Related: | 3rv5, 1j1d, 1wrk, 1mxl, 1ap4, 1spy, 3swb, 4gje, 4gjf, 4gjg |
| Gene: | TNNC, TNNC1 (HUMAN) |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Disease
[TNNC1_HUMAN] Defects in TNNC1 are the cause of cardiomyopathy dilated type 1Z (CMD1Z) [MIM:611879]. Dilated cardiomyopathy is a disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.[1] Defects in TNNC1 are the cause of familial hypertrophic cardiomyopathy type 13 (CMH13) [MIM:613243]. A hereditary heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death.[2] [3] [4] [5]
Function
[TNNC1_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
The amino-terminal domain of cardiac troponin C (cNTnC) is an essential Ca(2+) sensor found in cardiomyocytes. It undergoes a conformational change upon Ca(2+) binding and transduces the signal to the rest of the troponin complex to initiate cardiac muscle contraction. Two classical EF-hand motifs (EF1 and EF2) are present in cNTnC. Under physiological conditions, only EF2 binds Ca(2+); EF1 is a vestigial site that has lost its function in binding Ca(2+) owing to amino-acid sequence changes during evolution. Proteins with EF-hand motifs are capable of binding divalent cations other than calcium. Here, the crystal structure of wild-type (WT) human cNTnC in complex with Cd(2+) is presented. The structure of Cd(2+)-bound cNTnC with the disease-related mutation L29Q, as well as a structure with the residue differences D2N, V28I, L29Q and G30D (NIQD), which have been shown to have functional importance in Ca(2+) sensing at lower temperatures in ectothermic species, have also been determined. The structures resemble the overall conformation of NMR structures of Ca(2+)-bound cNTnC, but differ significantly from a previous crystal structure of Cd(2+)-bound cNTnC in complex with deoxycholic acid. The subtle structural changes observed in the region near the mutations may play a role in the increased Ca(2+) affinity. The 1.4 A resolution WT cNTnC structure, which is the highest resolution structure yet obtained for cardiac troponin C, reveals a Cd(2+) ion coordinated in the canonical pentagonal bipyramidal geometry in EF2 despite three residues in the loop being disordered. A Cd(2+) ion found in the vestigial ion-binding site of EF1 is coordinated in a noncanonical `distorted' octahedral geometry. A comparison of the ion coordination observed within EF-hand-containing proteins for which structures have been solved in the presence of Cd(2+) is presented. A refolded WT cNTnC structure is also presented.
The structure of cardiac troponin C regulatory domain with bound Cd(2+) reveals a closed conformation and unique ion coordination.,Zhang XL, Tibbits GF, Paetzel M Acta Crystallogr D Biol Crystallogr. 2013 May;69(Pt 5):722-34. doi:, 10.1107/S0907444913001182. Epub 2013 Apr 11. PMID:23633581[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Mogensen J, Murphy RT, Shaw T, Bahl A, Redwood C, Watkins H, Burke M, Elliott PM, McKenna WJ. Severe disease expression of cardiac troponin C and T mutations in patients with idiopathic dilated cardiomyopathy. J Am Coll Cardiol. 2004 Nov 16;44(10):2033-40. PMID:15542288 doi:S0735-1097(04)01700-0
- ↑ Hoffmann B, Schmidt-Traub H, Perrot A, Osterziel KJ, Gessner R. First mutation in cardiac troponin C, L29Q, in a patient with hypertrophic cardiomyopathy. Hum Mutat. 2001 Jun;17(6):524. PMID:11385718 doi:10.1002/humu.1143
- ↑ Schmidtmann A, Lindow C, Villard S, Heuser A, Mugge A, Gessner R, Granier C, Jaquet K. Cardiac troponin C-L29Q, related to hypertrophic cardiomyopathy, hinders the transduction of the protein kinase A dependent phosphorylation signal from cardiac troponin I to C. FEBS J. 2005 Dec;272(23):6087-97. PMID:16302972 doi:10.1111/j.1742-4658.2005.05001.x
- ↑ Landstrom AP, Parvatiyar MS, Pinto JR, Marquardt ML, Bos JM, Tester DJ, Ommen SR, Potter JD, Ackerman MJ. Molecular and functional characterization of novel hypertrophic cardiomyopathy susceptibility mutations in TNNC1-encoded troponin C. J Mol Cell Cardiol. 2008 Aug;45(2):281-8. doi: 10.1016/j.yjmcc.2008.05.003. Epub , 2008 May 11. PMID:18572189 doi:10.1016/j.yjmcc.2008.05.003
- ↑ Pinto JR, Parvatiyar MS, Jones MA, Liang J, Ackerman MJ, Potter JD. A functional and structural study of troponin C mutations related to hypertrophic cardiomyopathy. J Biol Chem. 2009 Jul 10;284(28):19090-100. doi: 10.1074/jbc.M109.007021. Epub, 2009 May 12. PMID:19439414 doi:10.1074/jbc.M109.007021
- ↑ Zhang XL, Tibbits GF, Paetzel M. The structure of cardiac troponin C regulatory domain with bound Cd(2+) reveals a closed conformation and unique ion coordination. Acta Crystallogr D Biol Crystallogr. 2013 May;69(Pt 5):722-34. doi:, 10.1107/S0907444913001182. Epub 2013 Apr 11. PMID:23633581 doi:10.1107/S0907444913001182
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