1fi5

<StructureSection load='1fi5' size='340' side='right'caption='[[1fi5]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''>

<table><tr><td colspan='2'>[[1fi5]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Chick Chick]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1ggs 1ggs]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FI5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FI5 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>

[[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 N-terminal domain of cardiac troponin I (cTnI) comprising residues 33-80 and lacking the cardiac-specific amino terminus forms a stable binary complex with the C-terminal domain of cardiac troponin C (cTnC) comprising residues 81-161. We have utilized heteronuclear multidimensional NMR to assign the backbone and side-chain resonances of Ca2+-saturated cTnC(81-161) both free and bound to cTnI(33-80). No significant differences were observed between secondary structural elements determined for free and cTnI(33-80)-bound cTnC(81-161). We have determined solution structures of Ca2+-saturated cTnC(81-161) free and bound to cTnI(33-80). While the tertiary structure of cTnC(81-161) is qualitatively similar to that observed free in solution, the binding of cTnI(33-80) results mainly in an opening of the structure and movement of the loop region between helices F and G. Together, these movements provide the binding site for the N-terminal domain of cTnI. The putative binding site for cTnI(33-80) was determined by mapping amide proton and nitrogen chemical shift changes, induced by the binding of cTnI(33-80), onto the C-terminal cTnC structure. The binding interface for cTnI(33-80), as suggested from chemical shift changes, involves predominantly hydrophobic interactions located in the expanded hydrophobic pocket. The largest chemical shift changes were observed in the loop region connecting helices F and G. Inspection of available TnC sequences reveals that these residues are highly conserved, suggesting a common binding motif for the Ca2+/Mg2+-dependent interaction site in the TnC/TnI complex.

Solution structures of the C-terminal domain of cardiac troponin C free and bound to the N-terminal domain of cardiac troponin I.,Gasmi-Seabrook GM, Howarth JW, Finley N, Abusamhadneh E, Gaponenko V, Brito RM, Solaro RJ, Rosevear PR Biochemistry. 1999 Jun 29;38(26):8313-22. PMID:10387077<ref>PMID:10387077</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 1fi5" style="background-color:#fffaf0;"></div>

*[[Troponin|Troponin]]

[[Category: Chick]]

[[Category: Abusamhadneh, E]]

[[Category: Brito, R M]]

[[Category: Finley, N]]

[[Category: Gaponenko, V]]

[[Category: Gasmi-Seabrook, G M]]

[[Category: Howarth, J W]]

[[Category: Rosevear, P R]]

[[Category: Solaro, R J]]

[[Category: Troponin c-troponin i interaction]]