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== | ==N-DOMAIN OF TROPONIN C FROM CHICKEN SKELETAL MUSCLE, NMR, MINIMIZED AVERAGE STRUCTURE== | ||
<StructureSection load='1zac' size='340' side='right'caption='[[1zac]]' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1zac]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ZAC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1ZAC FirstGlance]. <br> | |||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1zac FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1zac OCA], [https://pdbe.org/1zac PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1zac RCSB], [https://www.ebi.ac.uk/pdbsum/1zac PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1zac ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/TNNC2_CHICK 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 == | |||
[[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/za/1zac_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/main_output.php?pdb_ID=1zac ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Contractile activity of skeletal muscle is triggered by a Ca2+-induced "opening" of the regulatory N-domain of troponin C (apo-NTnC residues 1-90). This structural transition has become a paradigm for large-scale conformational changes that affect the interaction between proteins. The regulatory domain is comprised of two basic structural elements: one contributed by the N-, A-, and D-helices (NAD unit) and the other by the B- and C-helices (BC unit). The Ca2+-induced opening is characterized by a movement of the BC unit away from the NAD unit with a concomitant change in conformation at two hinges (Glu41 and Val65) of the BC unit. To examine the effect of low temperatures on this Ca2+-induced structural change and the implications for contractile regulation, we have examined nuclear magnetic resonance (NMR) spectral changes of apo-NTnC upon decreasing the temperature from 30 to 4 degrees C. In addition, we have determined the solution structure of apo-NTnC at 4 degrees C using multinuclear multidimensional NMR spectroscopy. Decreasing temperatures induce a decrease in the rates and amplitudes of pico to nanosecond time scale backbone dynamics and an increase in alpha-helical content for the terminal helices of apo-NTnC. In addition, chemical shift changes for the Halpha resonances of Val65 and Asp66, the hinge residues of the BC, unit were observed. Compared to the solution structure of apo-NTnC determined at 30 degrees C, the BC unit packs more tightly against the NAD unit in the solution structure determined at 4 degrees C. Concomitant with the tighter packing of the BC and NAD structural units, a decrease in the total exposed hydrophobic surface area is observed. The results have broad implications relative to structure determination of proteins in the presence of large domain movements, and help to elucidate the relevance of structures determined under different conditions of physical state and temperature, reflecting forces ranging from crystal packing to solution dynamics. | Contractile activity of skeletal muscle is triggered by a Ca2+-induced "opening" of the regulatory N-domain of troponin C (apo-NTnC residues 1-90). This structural transition has become a paradigm for large-scale conformational changes that affect the interaction between proteins. The regulatory domain is comprised of two basic structural elements: one contributed by the N-, A-, and D-helices (NAD unit) and the other by the B- and C-helices (BC unit). The Ca2+-induced opening is characterized by a movement of the BC unit away from the NAD unit with a concomitant change in conformation at two hinges (Glu41 and Val65) of the BC unit. To examine the effect of low temperatures on this Ca2+-induced structural change and the implications for contractile regulation, we have examined nuclear magnetic resonance (NMR) spectral changes of apo-NTnC upon decreasing the temperature from 30 to 4 degrees C. In addition, we have determined the solution structure of apo-NTnC at 4 degrees C using multinuclear multidimensional NMR spectroscopy. Decreasing temperatures induce a decrease in the rates and amplitudes of pico to nanosecond time scale backbone dynamics and an increase in alpha-helical content for the terminal helices of apo-NTnC. In addition, chemical shift changes for the Halpha resonances of Val65 and Asp66, the hinge residues of the BC, unit were observed. Compared to the solution structure of apo-NTnC determined at 30 degrees C, the BC unit packs more tightly against the NAD unit in the solution structure determined at 4 degrees C. Concomitant with the tighter packing of the BC and NAD structural units, a decrease in the total exposed hydrophobic surface area is observed. The results have broad implications relative to structure determination of proteins in the presence of large domain movements, and help to elucidate the relevance of structures determined under different conditions of physical state and temperature, reflecting forces ranging from crystal packing to solution dynamics. | ||
Low-temperature-induced structural changes in the Apo regulatory domain of skeletal muscle troponin C.,Tsuda S, Miura A, Gagne SM, Spyracopoulos L, Sykes BD Biochemistry. 1999 May 4;38(18):5693-700. PMID:10231519<ref>PMID:10231519</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1zac" style="background-color:#fffaf0;"></div> | |||
==See Also== | |||
*[[Troponin 3D structures|Troponin 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Gallus gallus]] | [[Category: Gallus gallus]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Gagne | [[Category: Gagne SM]] | ||
[[Category: Miura | [[Category: Miura A]] | ||
[[Category: Spyracopoulos | [[Category: Spyracopoulos L]] | ||
[[Category: Sykes | [[Category: Sykes BD]] | ||
[[Category: Tsuda | [[Category: Tsuda S]] | ||