title: Structurally diverse dehydroshikimate dehydratase variants participate in microbial quinate catabolism.
abstract: Quinate and shikimate can be degraded by a number of microbes. Dehydroshikimate dehydratases (DSDs) play a central role in this process, catalyzing the conversion of 3-dehydroshikimate to protocatechuate, a common intermediate of aromatic degradation pathways. DSDs have applications in metabolic engineering for the production of valuable protocatechuate-derived molecules. Although a number of Gram-negative bacteria are known to catabolize quinate and shikimate, only limited information exists on the quinate/shikimate catabolic enzymes found in these organisms. Here, we have functionally and structurally characterized a putative DSD designated QuiC1, which is present in some pseudomonads. The QuiC1 protein is not related by sequence with previously identified DSDs from the Gram-negative genus, Acinetobacter, but instead shows limited sequence identity in its N-terminal half with fungal DSDs. Analysis of a Pseudomonas aeruginosa quiC1 gene knock-out demonstrates that it is important for growth on either quinate or shikimate. The structure of a QuiC1 enzyme from P. putida reveals that the protein is a fusion of two distinct modules: an N-terminal sugar phosphate isomerase-like domain associated with DSD activity and a novel C-terminal hydroxyphenylpyruvate dioxygenase-like domain. The results of this study highlight the considerable diversity of enzymes that participate in quinate/shikimate catabolism in different microbes.
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2.
authors.forename: James
authors.initials: J
authors.lastname: Peek
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, WI, 53211-3209, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Roman
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, WI, 53211-3209, USA.
authors.forename: Graham R
authors.initials: GR
authors.lastname: Moran
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada, M5S 3B2.|Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario, Canada, M5S 3B2.
authors.forename: Dinesh
authors.initials: D
authors.lastname: Christendat
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D006836:Hydro-Lyases / Q000737:chemistry / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods; D053858:Metabolic Networks and Pathways; D011801:Quinic Acid / Q000378:metabolism; D012765:Shikimic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D011801:Quinic Acid; C096387:3-dehydroshikimate; D012765:Shikimic Acid; D000429:Alcohol Oxidoreductases; C022641:Shikimate dehydrogenase; D006836:Hydro-Lyases