View source for 5tnc

==REFINED CRYSTAL STRUCTURE OF TROPONIN C FROM TURKEY SKELETAL MUSCLE AT 2.0 ANGSTROMS RESOLUTION==
<StructureSection load='5tnc' size='340' side='right' caption='[[5tnc]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5tnc]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Meleagris_gallopavo Meleagris gallopavo]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=2tnc 2tnc]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5TNC OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5TNC FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5tnc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5tnc OCA], [http://www.rcsb.org/pdb/explore.do?structureId=5tnc RCSB], [http://www.ebi.ac.uk/pdbsum/5tnc PDBsum]</span></td></tr>
</table>
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/tn/5tnc_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/chain_selection.php?pdb_ID=2ata ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure of troponin C from turkey skeletal muscle has been refined at 2.0 A resolution (1 A = 0.1 nm). The resulting crystallographic R factor (R = sigma[[Fo[-[Fc[[/sigma[Fo[, where [Fo[ and [Fc[ are the observed and calculated structure factor amplitudes) is 0.155 for the 8054 reflections with intensities I greater than or equal to 2 sigma(I) within the 10 A to 2.0 A resolution range. With 66% of the residues in helical conformation, troponin C provides a good sample for helix analysis. The mean alpha-helix dihedral angles (phi, psi = -62 degrees, -42 degrees) agree with values observed for helical regions in other proteins. The helices are all curved and/or kinked. In particular, the 31 amino acid long inter-domain helix is smoothly curved, with a rather large radius of curvature of 137 A. Helix packing is different in the Ca2+-free domain (N-terminal) and the Ca2+-bound domain (C-terminal). The inter-helix angles for the two helix-loop-helix motifs in the regulatory domain are 133 degrees and 151 degrees, whereas the value for the two motifs in the C-terminal domain is 110 degrees, as observed in the EF-hands of parvalbumin. These differences affect the packing of the respective hydrophobic cores of each domain, in particular the disposition of aromatic rings. Pairwise arrangement of Ca2+-binding loops is common to both states, but the conformation is markedly different. Conversion of one to the other can be achieved by small cumulative changes of main-chain dihedral angles. The integrity of loop structure is maintained by numerous electrostatic interactions. Both salt bridges and carboxyl-carboxylate interactions are observed in TnC. There are more intramolecular (9) than intermolecular (1) salt bridges. Carboxyl-carboxylate interactions occur because the pH of the crystals is 5.0 and there is a multitude of aspartate and glutamate residues. One is intramolecular and four are intermolecular. Polar side-chain interactions occur more commonly with main-chain carbonyls and amides than with other polar side-chains. These interactions are mostly short range, and are similar to those observed in other proteins with one exception: negatively charged side-chains interact more frequently with main-chain carbonyl oxygen atoms. However, out of 19 such interactions, 10 involve oxygen atoms of the Ca2+ ligands. These unfavorable interactions are compensated by the favorable interactions with the Ca2+ ions and with main-chain amides. They are a trivial consequence of the tight fold of the Ca2+-binding loops.

Refined crystal structure of troponin C from turkey skeletal muscle at 2.0 A resolution.,Herzberg O, James MN J Mol Biol. 1988 Oct 5;203(3):761-79. PMID:3210231<ref>PMID:3210231</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Troponin|Troponin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Meleagris gallopavo]]
[[Category: Herzberg, O]]
[[Category: James, M N.G]]
[[Category: Contractile system protein]]