1xal: Difference between revisions

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

Dehydroquinate synthase (DHQS) is a potential target for the development of novel broad-spectrum antimicrobial drugs, active against both prokaryotes and lower eukaryotes. Structures have been reported for Aspergillus nidulans DHQS (AnDHQS) in complexes with a range of ligands. Analysis of these AnDHQS structures showed that a large-scale domain movement occurs during the normal catalytic cycle, with a complex series of structural elements propagating substrate binding-induced conformational changes away from the active site to distal locations. Compared to corresponding fungal enzymes, DHQS from bacterial species are both mono-functional and significantly smaller. We have therefore determined the structure of Staphylococcus aureus DHQS (SaDHQS) in five liganded states, allowing comparison of ligand-induced conformational changes and mechanisms of domain closure between fungal and bacterial enzymes. This comparative analysis shows that substrate binding initiates a large-scale domain closure in both species' DHQS and that the active site stereochemistry, of the catalytically competent closed-form enzyme thus produced, is also highly conserved. However, comparison of AnDHQS and SaDHQS open-form structures, and analysis of the putative dynamic processes by which the transition to the closed-form states are made, shows a far lower degree of similarity, indicating a significant structural divergence. As a result, both the nature of the propagation of conformational change and the mechanical systems involved in this propagation are quite different between the DHQSs from the two species.

1XAL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Staphylococcus_aureus Staphylococcus aureus] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=NAD:'>NAD</scene> and <scene name='pdbligand=CRB:'>CRB</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/3-dehydroquinate_synthase 3-dehydroquinate synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.3.4 4.2.3.4] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XAL OCA].  

[[Category: Hawkins, A R.]]

[[Category: Nichols, C E.]]

[[Category: Stammers, D K.]]

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