title: The biosynthesis of 3-amino-5-hydroxybenzoic acid (AHBA), the precursor of mC7N units in ansamycin and mitomycin antibiotics: a review.
abstract: The aminoshikimate pathway of formation of 3-amino-5-hydroxybenzoic acid (AHBA), the precursor of ansamycin and other antibiotics is reviewed. In this biosynthesis, genes for kanosamine formation have been recruited from other genomes, to provide a nitrogenous precursor. Kanosamine is then phosphorylated and converted by common cellular enzymes into 1-deoxy-1-imino-erythrose 4-phosphate, the substrate for the formation of aminoDAHP. This is converted via 5-deoxy-5-aminodehydroquinic acid and 5-deoxy-5-aminodehydroshikimic acid into AHBA. Remarkably, the pyridoxal phosphate enzyme AHBA synthase seems to have two catalytic functions: As a homodimer, it catalyzes the last reaction in the pathway, the aromatization of 5-deoxy-5-aminodehydroshikimic acid, and at the beginning of the pathway in a complex with the oxidoreductase RifL it catalyzes the transamination of UDP-3-keto-D-glucose. The AHBA synthase gene also serves as a useful tool in the genetic screening for new ansamycins and other AHBA-derived natural products.
authors.affiliation: Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA. floss@chem.washington.edu
authors.forename: Heinz G
authors.initials: HG
authors.lastname: Floss
authors.forename: Tin-Wein
authors.initials: TW
authors.lastname: Yu
authors.forename: Kenji
authors.initials: K
authors.lastname: Arakawa
mesh_terms: D000192:Actinomycetales / Q000201:enzymology / Q000378:metabolism*; D062365:Aminobenzoates / Q000378:metabolism*; D006836:Hydro-Lyases / Q000378:metabolism*; D062385:Hydroxybenzoates; D016685:Mitomycin / Q000096:biosynthesis*; D015394:Molecular Structure; D017828:Rifabutin / Q000378:metabolism*
chemical_list: D062365:Aminobenzoates; D062385:Hydroxybenzoates; D017828:Rifabutin; D016685:Mitomycin; C031509:3-amino-5-hydroxybenzoic acid; C111160:3-amino-5-hydroxybenzoic acid synthase; D006836:Hydro-Lyases