Dehydroquinate synthase (DHQS) has long been regarded as a catalytic marvel because of its ability to perform several consecutive chemical reactions in one active site. There has been considerable debate as to whether DHQS is actively involved in all these steps, or whether several steps occur spontaneously, making DHQS a spectator in its own mechanism ...
Dehydroquinate synthase (DHQS) has long been regarded as a catalytic marvel because of its ability to perform several consecutive chemical reactions in one active site. There has been considerable debate as to whether DHQS is actively involved in all these steps, or whether several steps occur spontaneously, making DHQS a spectator in its own mechanism. DHQS performs the second step in the shikimate pathway, which is required for the synthesis of aromatic compounds in bacteria, microbial eukaryotes and plants. This enzyme is a potential target for new antifungal and antibacterial drugs as the shikimate pathway is absent from mammals and DHQS is required for pathogen virulence. Here we report the crystal structure of DHQS, which has several unexpected features, including a previously unobserved mode for NAD+-binding and an active-site organization that is surprisingly similar to that of alcohol dehydrogenase, in a new protein fold. The structure reveals interactions between the active site and a substrate-analogue inhibitor, which indicate how DHQS can perform multistep catalysis without the formation of unwanted by-products.
Related Citations:
Reactivation of 3-Dehydroquinate Synthase by Lanthanide Cations Moore, J.D., Skinner, M.A., Swatman, D.R., Hawkins, A.R., Brown, K.A. (1998) J Am Chem Soc 120: 7105
Cyclohexenyl and Cyclohexylidene Inhibitors of 3-Dehydroquinate Synthase: Active Site Interactions Relevant to Enzyme Mechanism and Inhibitor Design Montchamp, J.L., Frost, J.W. (1997) J Am Chem Soc 119: 7645
Efficient Independent Activity of a Monomeric, Monofunctional Dehydroquinate Synthase Derived from the N-Terminus of the Pentafunctional Arom Protein of Aspergillus Nidulans Moore, J.D., Coggins, J.R., Virden, R., Hawkins, A.R. (1994) Biochem J 301: 297
The Pre-Chorismate (Shikimate) and Quinate Pathways in Filamentous Fungi: Theoretical and Practical Aspects Hawkins, A.R., Lamb, H.K., Moore, J.D., Charles, I.G., Roberts, C.F. (1993) J Gen Microbiol 139: 2891
Overproduction in Escherichia Coli of the Dehydroquinate Synthase Domain of the Aspergillus Nidulans Pentafunctional Arom Protein Van Den Hombergh, J.P., Moore, J.D., Charles, I.G., Hawkins, A.R. (1992) Biochem J 284: 861
Dehydroquinate Synthase: The Use of Substrate Analogues to Probe the Early Steps of the Catalyzed Reaction Bender, S.L., Widlanski, T., Knowles, J.R. (1989) Biochemistry 28: 7560
The Enzymatic Conversion of 3-Deoxy-D-Arabino-Heptulosinic Acid 7-Phosphate to 5-Dehydroquinate Srinivasen, P.R., Rothchild, J., Sprinson, D.B. (1963) J Biol Chem 238: 3176
Organizational Affiliation:
Division for Protein Structure, National Institute for Medical Research, Mill Hill, London, UK.
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