1srd

From Proteopedia

proteopedia linkproteopedia link

spinqualitylabelsall models 1srd, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

THREE-DIMENSIONAL STRUCTURE OF CU,ZN-SUPEROXIDE DISMUTASE FROM SPINACH AT 2.0 ANGSTROMS RESOLUTION

Overview

The three-dimensional structure of Cu,Zn-superoxide dismutase from spinach, leaves has been determined by X-ray crystal structure analysis. The atomic, coordinates were refined at 2.0 A resolution using the Hendrickson and, Konnert program for stereochemically restrained refinement against, structure factors, which allowed the use of non-crystallographic symmetry., The crystallographic residual error for the refined model was 24.9%, with, a root mean square deviation of 0.03 A from the ideal bond length and an, average atomic temperature factor of 9.6 A. A dimeric molecule of the, enzyme is comprised of two identical subunits related by a, non-crystallographic 2-fold axis. Each subunit of 154 amino acid residues, is composed primarily of eight anti-parallel beta-strands that form a, flattened cylinder, plus three external loops. The main-chain hydrogen, bonds primarily link the beta-strands. The overall structure of this, enzyme is quite similar to that of the bovine dismutase except for some, parts. The single disulfide bridge (Cys57-Cys146) and the salt bridge, (Arg79-Asp101) may stabilize the loop regions of the structure. The Cu2+, and Zn2+ ions in the active site lie 6.1 A apart at the bottom of the long, channel. The Cu2+ ligands (ND1 of His-46, and NE2 of His-48, -63, and, -120) show an uneven tetrahedral distortion from a square plane. The Zn2+, ligands (ND1 of His-63, -71, and -80 and OD1 of Asp-83) show an almost, tetrahedral geometry. The imidazole ring of His-63 forms a bridge between, the Cu2+ and Zn2+ ions.(ABSTRACT TRUNCATED AT 250 WORDS)

About this Structure

1SRD is a Single protein structure of sequence from Spinacia oleracea with CU and ZN as ligands. Active as Superoxide dismutase, with EC number 1.15.1.1 Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of Cu,Zn-superoxide dismutase from spinach at 2.0 A resolution., Kitagawa Y, Tanaka N, Hata Y, Kusunoki M, Lee GP, Katsube Y, Asada K, Aibara S, Morita Y, J Biochem (Tokyo). 1991 Mar;109(3):477-85. PMID:1880134

Page seeded by OCA on Wed Nov 21 02:35:57 2007