title: Functional characterization by genetic complementation of aroB-encoded dehydroquinate synthase from Mycobacterium tuberculosis H37Rv and its heterologous expression and purification.
abstract: The recent recrudescence of Mycobacterium tuberculosis infection and the emergence of multidrug-resistant strains have created an urgent need for new therapeutics against tuberculosis. The enzymes of the shikimate pathway are attractive drug targets because this route is absent in mammals and, in M. tuberculosis, it is essential for pathogen viability. This pathway leads to the biosynthesis of aromatic compounds, including aromatic amino acids, and it is found in plants, fungi, bacteria, and apicomplexan parasites. The aroB-encoded enzyme dehydroquinate synthase is the second enzyme of this pathway, and it catalyzes the cyclization of 3-deoxy-D-arabino-heptulosonate-7-phosphate in 3-dehydroquinate. Here we describe the PCR amplification and cloning of the aroB gene and the overexpression and purification of its product, dehydroquinate synthase, to homogeneity. In order to probe where the recombinant dehydroquinate synthase was active, genetic complementation studies were performed. The Escherichia coli AB2847 mutant was used to demonstrate that the plasmid construction was able to repair the mutants, allowing them to grow in minimal medium devoid of aromatic compound supplementation. In addition, homogeneous recombinant M. tuberculosis dehydroquinate synthase was active in the absence of other enzymes, showing that it is homomeric. These results will support the structural studies with M. tuberculosis dehydroquinate synthase that are essential for the rational design of antimycobacterial agents.
authors.affiliation: Centro de Pesquisas em Biologia Molecular e Funcional, Pontifícia Universidade Católica do Rio Grande do Sul, Av. Ipiranga, 6681, Tecnopuc, Prédio 92A, 90619-900, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Jordana Dutra
authors.initials: JD
authors.lastname: de Mendonça
authors.forename: Fernanda
authors.initials: F
authors.lastname: Ely
authors.forename: Mario Sergio
authors.initials: MS
authors.lastname: Palma
authors.forename: Jeverson
authors.initials: J
authors.lastname: Frazzon
authors.forename: Luiz Augusto
authors.initials: LA
authors.lastname: Basso
authors.forename: Diógenes Santiago
authors.initials: DS
authors.lastname: Santos
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D017353:Gene Deletion; D015870:Gene Expression; D005816:Genetic Complementation Test; D006801:Humans; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D019761:Phosphorus-Oxygen Lyases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011994:Recombinant Proteins; C020001:3-dehydroquinate synthetase; D019761:Phosphorus-Oxygen Lyases