Chemical Characterisation of Disruptants of the Streptomyces coelicolor A3(2). ActVI Genes Involved in Actinorhodin Biosynthesis.

Abstract

The actVl genetic region ofStreptomyces coelicolor A3(2) is part of the biosynthetic gene cluster of actinorhodin (ACT), the act cluster, consisting of six ORFs: ORFB, ORFA, ORF1, ORF2, ORF3, ORF4. A newly devised method of ACTdetection with a combination of HPLC and LC/MSwas applied to the analysis of the disruptants of each OREACTwas produced by those of ORFB, ORFA, ORF3, and ORF4. Instead of ACT, the ORF1disruptant produced 3,8-dihydroxy-l -methylanthraquinone-2-carboxylic acid (DMAC)and aloesaponarin II as shunt products. The ORF2 disruptant gave 4-dihydro-9-hydroxy-l -methyl-1 0-oxo-3-//-naphtho-[2,3- pp.144 -152

Cloning, sequencing and heterologous expression of the medermycin biosynthetic gene cluster of Streptomyces sp. AM-7161: towards comparative analysis of the benzoisochromanequinone gene clusters

“…Genome integration was confirmed by colony PCR with the primer set Neo-F and Neo-R for kanamycin-resistant clones as described by Ishikawa et al (2000). Transformants were liquid-cultured as described previously (Taguchi et al, 2000a). The medium separated from the broth by centrifugation was directly subjected to reversed-phase HPLC analysis on a TOSOH 8020 system under the following conditions: column, TSK gel ODS-80TM (4?6 mm i.d.…”

“…3). Our earlier experiments (Taguchi et al, 2000a) suggested the actVI-ORF2 protein, an enoyl reductase homologue, to function as the second reductase at C-15 to complete the (3S, 15R) configuration. The presence of another homologue, actVI-ORF4, prompted us to propose that the product might assist an unusual mode of reduction of (S)-DNPA (Taguchi et al, 2000a).…”

“…Our earlier experiments (Taguchi et al, 2000a) suggested the actVI-ORF2 protein, an enoyl reductase homologue, to function as the second reductase at C-15 to complete the (3S, 15R) configuration. The presence of another homologue, actVI-ORF4, prompted us to propose that the product might assist an unusual mode of reduction of (S)-DNPA (Taguchi et al, 2000a). The reduction was proposed to proceed in two coupled steps, with stereospecific reduction (by ActVI-ORF2) of the double bond between C-14 and C-15 followed by isomerization (by ActVI-ORF4) to afford the a,b-unsaturated carbonyl structure, thus accomplishing the 1,4-reduction concerning C-15 and C-6.…”

“…The phenotypic and chemical characterization of an actVI-ORF3 disruptant (Fernández-Moreno et al, 1992;Taguchi et al, 2000a) suggested that the product might catalyse chemically spontaneous processes such as the hemiketal formation and dehydration to afford (S)-DNPA (Fig. 3).…”

Fogacin, a Novel Cyclic Octaketide Produced by Streptomyces Strain Tü 6319

“…3) which are often found in experiments with streptomycetes mutants bearing manipulations in the cyclase functions of type II polyketide synthases (PKS) [6,7] and are under ongoing investigations [8]. In these experiments 2 and 3 turned out to be important key metabolites for the elucidation of the biosynthetic pathway of 4.…”