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1ncx
From Proteopedia
(New page: 200px<br /><applet load="1ncx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ncx, resolution 1.8Å" /> '''TROPONIN C'''<br /> ...) |
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| - | [[Image:1ncx.jpg|left|200px]]<br /><applet load="1ncx" size=" | + | [[Image:1ncx.jpg|left|200px]]<br /><applet load="1ncx" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ncx, resolution 1.8Å" /> | caption="1ncx, resolution 1.8Å" /> | ||
'''TROPONIN C'''<br /> | '''TROPONIN C'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The crystal structures of three metal complexes of troponin C (TnC) have | + | The crystal structures of three metal complexes of troponin C (TnC) have been determined and refined where the two occupied structural Ca(2+) sites in the C domain have been substituted by Mn(2+), Cd(2+) and Tb(3+). The X-ray intensity data were collected to 2.1, 1.8 and 1.8 A resolution, respectively, on the three metal complexes, which are isomorphous with Ca-TnC. The three complexes have r.m.s. deviations of 0.27, 0.25 and 0.35 A, respectively, for all protein atoms, from Ca-TnC. Irrespective of the charge on the metal (+2 or +3), the occupied sites 3 and 4 exhibit a distorted pentagonal bipyramidal coordination, like Ca-TnC, with seven ligands, six from the 12-residue binding loop and the seventh from a water molecule. Mn(2+) at site 4 seems to display a longer distance to one of the carboxyl bidentate ligands representing an intermediate coordination simulating the six-coordinate Mg(2+). The carboxyl O atoms of the bidentate Glu12 are displaced on the side of the equatorial plane passing through the remaining three ligands with one O atom closer to the plane (Delta of 0.11 to 0.76 A) than the other (Delta of 0.93 to 1.38 A). The two axial ligands are an aspartic carboxyl O atom and a water molecule. The metal is displaced (0.18 to 0.56 A) towards the water facing the water channel. |
==About this Structure== | ==About this Structure== | ||
| - | 1NCX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with CD and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1NCX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] with <scene name='pdbligand=CD:'>CD</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NCX OCA]. |
==Reference== | ==Reference== | ||
| Line 13: | Line 13: | ||
[[Category: Gallus gallus]] | [[Category: Gallus gallus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Rao, S | + | [[Category: Rao, S T.]] |
[[Category: Sundaralingam, M.]] | [[Category: Sundaralingam, M.]] | ||
[[Category: CD]] | [[Category: CD]] | ||
| Line 21: | Line 21: | ||
[[Category: muscle protein]] | [[Category: muscle protein]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:04:44 2008'' |
Revision as of 12:04, 21 February 2008
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TROPONIN C
Overview
The crystal structures of three metal complexes of troponin C (TnC) have been determined and refined where the two occupied structural Ca(2+) sites in the C domain have been substituted by Mn(2+), Cd(2+) and Tb(3+). The X-ray intensity data were collected to 2.1, 1.8 and 1.8 A resolution, respectively, on the three metal complexes, which are isomorphous with Ca-TnC. The three complexes have r.m.s. deviations of 0.27, 0.25 and 0.35 A, respectively, for all protein atoms, from Ca-TnC. Irrespective of the charge on the metal (+2 or +3), the occupied sites 3 and 4 exhibit a distorted pentagonal bipyramidal coordination, like Ca-TnC, with seven ligands, six from the 12-residue binding loop and the seventh from a water molecule. Mn(2+) at site 4 seems to display a longer distance to one of the carboxyl bidentate ligands representing an intermediate coordination simulating the six-coordinate Mg(2+). The carboxyl O atoms of the bidentate Glu12 are displaced on the side of the equatorial plane passing through the remaining three ligands with one O atom closer to the plane (Delta of 0.11 to 0.76 A) than the other (Delta of 0.93 to 1.38 A). The two axial ligands are an aspartic carboxyl O atom and a water molecule. The metal is displaced (0.18 to 0.56 A) towards the water facing the water channel.
About this Structure
1NCX is a Single protein structure of sequence from Gallus gallus with and as ligands. Full crystallographic information is available from OCA.
Reference
X-ray structures of Mn, Cd and Tb metal complexes of troponin C., Rao ST, Satyshur KA, Greaser ML, Sundaralingam M, Acta Crystallogr D Biol Crystallogr. 1996 Sep 1;52(Pt 5):916-22. PMID:15299599
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