2cst
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(New page: 200px<br /><applet load="2cst" size="450" color="white" frame="true" align="right" spinBox="true" caption="2cst, resolution 1.9Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 07:07, 21 November 2007
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CRYSTAL STRUCTURE OF THE CLOSED FORM OF CHICKEN CYTOSOLIC ASPARTATE AMINOTRANSFERASE AT 1.9 ANGSTROMS RESOLUTION
Overview
The crystal structure of chicken cytosolic aspartate aminotransferase, (cAATase; EC 2.6.1.1) has been solved and refined at 1.9 A resolution., Orthorhombic crystals, space group P2(1)2(1)2(1), a = 56.4 A, b = 126.0 A, and c = 142.3 A, were grown from polyethylene glycol solutions in the, presence of maleate, a dicarboxylic inhibitor that forms a Michaelis-like, complex. The pyridoxal form of the enzyme was used for crystallization., Diffraction data were collected using synchrotron radiation. The structure, of the new orthorhombic crystal form was solved by molecular replacement, using the partially refined 2.8 A resolution structure of the high-salt, crystal form as a search model. The final value of the crystallographic, R-factor after rigid body and restrained least-squares refinement is 0.175, with very good model geometry. The two 2-fold-related subunits of cAATase, have distinct environments in the crystal lattice. Domain movement is, strictly hindered by the lattice contacts in one subunit, while the second, one possesses conformational freedom. Despite their different, environments, both subunits were found in the closed conformation with one, maleate molecule tightly bound in each active site. The present study, allows a detailed comparison of the highly refined structures of the, aspartate aminotransferase isozymes, and thus provide better insight into, the role of conserved and variable residues in substrate recognition and, catalysis.
About this Structure
2CST is a Single protein structure of sequence from Gallus gallus with PLP and MAE as ligands. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of the closed form of chicken cytosolic aspartate aminotransferase at 1.9 A resolution., Malashkevich VN, Strokopytov BV, Borisov VV, Dauter Z, Wilson KS, Torchinsky YM, J Mol Biol. 1995 Mar 17;247(1):111-24. PMID:7897655
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