title: Interdomain Conformational Changes Provide Allosteric Regulation en Route to Chorismate.
abstract: Multifunctional proteins play a variety of roles in metabolism. Here, we examine the catalytic function of the combined 3-deoxy-d-arabinoheptulosonate-7-phosphate synthase (DAH7PS) and chorismate mutase (CM) fromGeobacillussp. DAH7PS operates at the start of the biosynthetic pathway for aromatic metabolites, whereas CM operates in a dedicated branch of the pathway for the biosynthesis of amino acids tyrosine and phenylalanine. In line with sequence predictions, the two catalytic functions are located in distinct domains, and these two activities can be separated and retain functionality. For the full-length protein, prephenate, the product of the CM reaction, acts as an allosteric inhibitor for the DAH7PS. The crystal structure of the full-length protein with prephenate bound and the accompanying small angle x-ray scattering data reveal the molecular mechanism of the allostery. Prephenate binding results in the tighter association between the dimeric CM domains and the tetrameric DAH7PS, occluding the active site and therefore disrupting DAH7PS function. Acquisition of a physical gating mechanism to control catalytic function through gene fusion appears to be a general mechanism for providing allostery for this enzyme.
authors: From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand.
authors: Ali Reza
authors: AR
authors: Nazmi
authors: From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand.
authors: Eric J M
authors: EJM
authors: Lang
authors: From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand.
authors: Yu
authors: Y
authors: Bai
authors: the Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 5QY, United Kingdom.
authors: Timothy M
authors: TM
authors: Allison
authors: From the Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand.
authors: Mohamad H
authors: MH
authors: Othman
authors: the Australian Synchrotron, Clayton, Melbourne, Victoria 3168, Australia.|the Department of Biochemistry and Molecular Biology, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia.
authors: Santosh
authors: S
authors: Panjikar
authors: the School of Science, University of Waikato, Hamilton 3240, New Zealand, and.
authors: Vickery L
authors: VL
authors: Arcus
authors: the Maurice Wilkins Centre, Biomolecular Interaction Centre and Department of Chemistry, University of Canterbury, P. O. Box 4800, Christchurch 8140, New Zealand emily.parker@canterbury.ac.nz.
authors: Emily J
authors: EJ
authors: Parker
mesh_terms: D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000235:genetics / Q000378:metabolism*; D000494:Allosteric Regulation; D024322:Amino Acids, Aromatic / Q000378:metabolism; D002826:Chorismate Mutase / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D056506:Geobacillus / Q000201:enzymology; D012765:Shikimic Acid / Q000378:metabolism
chemical_list: D024322:Amino Acids, Aromatic; D012765:Shikimic Acid; D010723:3-Deoxy-7-Phosphoheptulonate Synthase; D002826:Chorismate Mutase
keywords: Bacillus; DAHPS; X-ray scattering; allosteric regulation; aromatic amino acid; chorismate mutase; crystal structure; inhibition mechanism; multifunctional enzyme; shikimate