1aj4

<StructureSection load='1aj4' size='340' side='right'caption='[[1aj4]], [[NMR_Ensembles_of_Models | 1 NMR models]]' scene=''>

<table><tr><td colspan='2'>[[1aj4]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Chick Chick]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AJ4 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AJ4 FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CTNC(A-CYS) ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9031 CHICK])</td></tr>

[[https://www.uniprot.org/uniprot/TNNC1_CHICK TNNC1_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.

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== Publication Abstract from PubMed ==

The regulation of cardiac muscle contraction must differ from that of skeletal muscles to effect different physiological and contractile properties. Cardiac troponin C (TnC), the key regulator of cardiac muscle contraction, possesses different functional and Ca2+-binding properties compared with skeletal TnC and features a Ca2+-binding site I, which is naturally inactive. The structure of cardiac TnC in the Ca2+-saturated state has been determined by nuclear magnetic resonance spectroscopy. The regulatory domain exists in a "closed" conformation even in the Ca2+-bound (the "on") state, in contrast to all predicted models and differing significantly from the calcium-induced structure observed in skeletal TnC. This structure in the Ca2+-bound state, and its subsequent interaction with troponin I (TnI), are crucial in determining the specific regulatory mechanism for cardiac muscle contraction. Further, it will allow for an understanding of the action of calcium-sensitizing drugs, which bind to cardiac TnC and are known to enhance the ability of cardiac TnC to activate cardiac muscle contraction.

Structure of cardiac muscle troponin C unexpectedly reveals a closed regulatory domain.,Sia SK, Li MX, Spyracopoulos L, Gagne SM, Liu W, Putkey JA, Sykes BD J Biol Chem. 1997 Jul 18;272(29):18216-21. PMID:9218458<ref>PMID:9218458</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1aj4" style="background-color:#fffaf0;"></div>

*[[Troponin|Troponin]]

[[Category: Chick]]

[[Category: Gagne, S M]]

[[Category: Li, M X]]

[[Category: Liu, W]]

[[Category: Putkey, J A]]

[[Category: Sia, S K]]

[[Category: Spyracopoulos, L]]

[[Category: Sykes, B D]]

[[Category: Regulatory]]