1ncx
From Proteopedia
OCA (Talk | contribs)
(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 /> ...)
Next diff →
Revision as of 20:01, 20 November 2007
|
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 CD and SO4 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
Page seeded by OCA on Tue Nov 20 22:08:52 2007
