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Structure of Arabidopsis Dehydroquinate Dhydratase-Shikimate Dehydrogeanse and Implications for Metabolic Channeling in the Shikimate Pathway

Journal Article · · Biochemistry
DOI:https://doi.org/10.1021/bi060366+· OSTI ID:914078
The bifunctional enzyme dehydroquinate dehydratase-shikimate dehydrogenase (DHQ-SDH) catalyzes the dehydration of dehydroquinate to dehydroshikimate and the reduction of dehydroshikimate to shikimate in the shikimate pathway. We report the first crystal structure of Arabidopsis DHQ-SDH with shikimate bound at the SDH site and tartrate at the DHQ site. The interactions observed in the DHQ-tartrate complex reveal a conserved mode for substrate binding between the plant and microbial DHQ dehydratase family of enzymes. The SDH-shikimate complex provides the first direct evidence of the role of active site residues in the catalytic mechanism. Site-directed mutagenesis and mechanistic analysis revealed that Asp 423 and Lys 385 are key catalytic groups and Ser 336 is a key binding group. The arrangement of the two functional domains reveals that the control of metabolic flux through the shikimate pathway is achieved by increasing the effective concentration of dehydroshikimate through the proximity of the two sites.
Research Organization:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Organization:
Doe - Office Of Science
DOE Contract Number:
AC02-98CH10886
OSTI ID:
914078
Report Number(s):
BNL--78646-2007-JA
Journal Information:
Biochemistry, Journal Name: Biochemistry Vol. 45; ISSN 0006-2960; ISSN BICHAW
Country of Publication:
United States
Language:
English