2csm

File:2csm.gif

spinqualitylabelsall models 2csm, resolution 2.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

TYR-BOUND T-STATE OF YEAST CHORISMATE MUTASE

OverviewOverview

The crystal structure of the tyrosine-bound T state of allosteric yeast, Saccharomyces cerevisiae chorismate mutase was solved by molecular, replacement at a resolution of 2.8 angstroms using a monomer of the, R-state structure as the search model. The allosteric inhibitor tyrosine, was found to bind in the T state at the same binding site as the, allosteric activator tryptophan binds in the R state, thus defining one, regulatory binding site for each monomer. Activation by tryptophan is, caused by the larger steric size of its side chain, thereby pushing apart, the allosteric domain of one monomer and helix H8 of the catalytic domain, of the other monomer. Inhibition is caused by polar contacts of tyrosine, with Arg-75 and Arg-76 of one monomer and with Gly-141, Ser-142, and, Thr-145 of the other monomer, thereby bringing the allosteric and, catalytic domains closer together. The allosteric transition includes an 8, degree rotation of each of the two catalytic domains relative to the, allosteric domains of each monomer (domain closure). Alternatively, this, transition can be described as a 15 degree rotation of the catalytic, domains of the dimer relative to each other.

About this StructureAbout this Structure

2CSM is a Single protein structure of sequence from Saccharomyces cerevisiae with TYR as ligand. Active as Chorismate mutase, with EC number 5.4.99.5 Structure known Active Sites: CAT and REG. Full crystallographic information is available from OCA.

ReferenceReference

Crystal structure of the T state of allosteric yeast chorismate mutase and comparison with the R state., Strater N, Hakansson K, Schnappauf G, Braus G, Lipscomb WN, Proc Natl Acad Sci U S A. 1996 Apr 16;93(8):3330-4. PMID:8622937

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