2scp

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spinqualitylabelsall models 2scp, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF A SARCOPLASMIC CALCIUM-BINDING PROTEIN FROM NEREIS DIVERSICOLOR REFINED AT 2.0 ANGSTROMS RESOLUTION

Overview

The crystal structure of a sarcoplasmic Ca(2+)-binding protein (SCP) from, the sandworm Nereis diversicolor has been determined and refined at 2.0 A, resolution using restrained least-squares techniques. The two molecules in, the crystallographic asymmetric unit, which are related by a, non-crystallographic 2-fold axis, were refined independently. The refined, model includes all 174 residues and three calcium ions for each molecule, as well as 213 water molecules. The root-mean-square difference in, co-ordinates for backbone atoms and calcium ions of the two molecules is, 0.51 A. The final crystallographic R-factor, based on 18,959 reflections, in the range 2.0 A less than or equal to d less than or equal to 7.0 A, with intensities exceeding 2.0 sigma, is 0.182. Bond lengths and bond, angles in the molecules have root-mean-square deviations from ideal values, of 0.013 A and 2.2 degrees, respectively. SCP has four distinct domains, with the typical helix-loop-helix (EF-hand) Ca(2+)-binding motif, although, the second Ca(2+)-binding domain is not functional due to amino acid, changes in the loop. The structure shows several unique features compared, to other Ca(2+)-binding proteins with four EF-hand domains. The overall, structure is highly compact and globular with a predominant hydrophobic, core, unlike the extended dumbbell-shaped structure of calmodulin or, troponin C. A hydrophobic tail at the COOH terminus adds to the structural, stability by packing against a hydrophobic pocket created by the folding, of the NH2 and COOH-terminal Ca(2+)-binding domain pairs. The first and, second domains show different helix-packing arrangements from any, previously described for Ca(2+)-binding proteins.

About this Structure

2SCP is a Single protein structure of sequence from Neanthes diversicolor with CA as ligand. This structure superseeds the now removed PDB entry 1SCP. Full crystallographic information is available from OCA.

Reference

Structure of a sarcoplasmic calcium-binding protein from Nereis diversicolor refined at 2.0 A resolution., Vijay-Kumar S, Cook WJ, J Mol Biol. 1992 Mar 20;224(2):413-26. PMID:1560459

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