1ncx

TROPONIN C

spinqualitylabelsall models 1ncx, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ncx is a 1 chain structure with sequence from Gallus gallus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CD, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [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 Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 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. 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 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Troponin

Proteopedia Page Contributors and Editors (what is this?)

OCA