title: CloQ, a prenyltransferase involved in clorobiocin biosynthesis.
abstract: Ring A (3-dimethylallyl-4-hydroxybenzoic acid) is a structural moiety of the aminocoumarin antibiotics novobiocin and clorobiocin. In the present study, the prenyltransferase involved in the biosynthesis of this moiety was identified from the clorobiocin producer (Streptomyces roseochromogenes), overexpressed, and purified. It is a soluble, monomeric 35-kDa protein, encoded by the structural gene cloQ. 4-Hydroxyphenylpyruvate and dimethylallyl diphosphate were identified as the substrates of this enzyme, with K(m) values determined as 25 and 35 microM, respectively. A gene inactivation experiment confirmed that cloQ is essential for ring A biosynthesis. Database searches did not reveal any similarity of CloQ to known prenyltransferases, and the enzyme did not contain the typical prenyl diphosphate binding site (N/D)DXXD. In contrast to most of the known prenyltransferases, the enzymatic activity was not dependent on the presence of magnesium, and in contrast to the membrane-bound polyprenyltransferases involved in ubiquinone biosynthesis, CloQ did not accept 4-hydroxybenzoic acid as substrate. CloQ and the similar NovQ from the novobiocin producer seem to belong to a new class of prenyltransferases.
authors.affiliation: Pharmazeutische Biologie, Auf der Morgenstelle 8, Universität Tübingen, 72076 Tübingen, Germany.
authors.forename: Florence
authors.initials: F
authors.lastname: Pojer
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Wemakor
authors.forename: Bernd
authors.initials: B
authors.lastname: Kammerer
authors.forename: Huawei
authors.initials: H
authors.lastname: Chen
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Walsh
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: Li
authors.forename: Lutz
authors.initials: L
authors.lastname: Heide
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D015139:Blotting, Southern; D002851:Chromatography, High Pressure Liquid; D003374:Coumarins / Q000737:chemistry; D004247:DNA / Q000378:metabolism; D004122:Dimethylallyltranstransferase / Q000737:chemistry* / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000378:metabolism; D017353:Gene Deletion; D007700:Kinetics; D013058:Mass Spectrometry; D008956:Models, Chemical; D008969:Molecular Sequence Data; D009154:Mutation; D009675:Novobiocin / Q000031:analogs & derivatives* / Q000096:biosynthesis* / Q000737:chemistry / Q000494:pharmacology; D013302:Streptomyces / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D003374:Coumarins; D004791:Enzyme Inhibitors; D009675:Novobiocin; C006260:clorobiocin; D014443:Tyrosine; D004247:DNA; D004122:Dimethylallyltranstransferase