1m8p: Difference between revisions

[[Image:1m8p.gif|left|200px]]<br /><applet load="1m8p" size="350" color="white" frame="true" align="right" spinBox="true"  

The structure of the cooperative hexameric enzyme ATP sulfurylase from Penicillium chrysogenum bound to its allosteric inhibitor, 3'-phosphoadenosine-5'-phosphosulfate (PAPS), was determined to 2.6 A resolution. This structure represents the low substrate-affinity T-state conformation of the enzyme. Comparison with the high substrate-affinity R-state structure reveals that a large rotational rearrangement of domains occurs as a result of the R-to-T transition. The rearrangement is accompanied by the 17 A movement of a 10-residue loop out of the active site region, resulting in an open, product release-like structure of the catalytic domain. Binding of PAPS is proposed to induce the allosteric transition by destabilizing an R-state-specific salt linkage between Asp 111 in an N-terminal domain of one subunit and Arg 515 in the allosteric domain of a trans-triad subunit. Disrupting this salt linkage by site-directed mutagenesis induces cooperative inhibition behavior in the absence of an allosteric effector, confirming the role of these two residues.

1M8P is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Penicillium_chrysogenum Penicillium chrysogenum] with <scene name='pdbligand=PPS:'>PPS</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Sulfate_adenylyltransferase Sulfate adenylyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.4 2.7.7.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1M8P OCA].  

[[Category: Fisher, A J.]]

[[Category: MacRae, I J.]]

[[Category: Segel, I H.]]

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