title: The missing link in petrobactin biosynthesis: asbF encodes a (-)-3-dehydroshikimate dehydratase.
abstract: The siderophore petrobactin harbors unique 3,4-dihydroxybenzoyl iron-liganding groups. These moieties are known to be synthesized from shikimate pathway precursors, but no reports of the biosynthetic enzymes responsible for this conversion have been published. The gene encoding AsbF from Bacillus thuringiensis 97-27 was overexpressed in an Escherichia coli host. AsbF rapidly and efficiently transforms (-)-3-dehydroshikimate (DHS) into 3,4-dihydroxybenzoate (k(cat)(DHS) = 217 +/- 10 min(-1); K(m)(DHS) = 125 +/- 14 microM) at 37 degrees C and has an absolute requirement for divalent metal. Finally, the pH versus k(cat)(DHS) profile revealed two ionizable groups (pK(a1) = 7.9 +/- 0.1, and pK(a2) = 9.3 +/- 0.1).
authors.affiliation: Biosciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Fox
authors.forename: Kinya
authors.initials: K
authors.lastname: Hotta
authors.forename: Chu-Young
authors.initials: CY
authors.lastname: Kim
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Koppisch
mesh_terms: D001413:Bacillus thuringiensis / Q000201:enzymology* / Q000235:genetics; D001549:Benzamides / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D006836:Hydro-Lyases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D005810:Multigene Family; D012765:Shikimic Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D001549:Benzamides; C450699:petrobactin; C096387:3-dehydroshikimate; D012765:Shikimic Acid; C044921:3-dehydroshikimate dehydratase; D006836:Hydro-Lyases