Streptomyces glaucescens

TABLE 2.4. Proteins Encoded in the Genomic Area Covering the str-Cluster of Streptomyces glaucescens GLA.O ATCC13032 (Accession Code AJ006985)... 

G Hintermann. Aspects of the genomic organisation in Streptomyces glaucescens. PhD dissertation, ETH, Zurich, Switzerland, 1984. 

MJ Bibb, S Biro, H Motamedi, JF Collins, CR Hutchinson. Analysis of the nucleotide sequence of the Streptomyces glaucescens tcml genes provides key information about the enzymology of polyketide biosynthesis. EMBO J 8 2727-2736, 1989. 

Figure 6 Cell-free biosynthesis of tetracenomycin F2. A strain of Streptomyces glaucescens in which the tetracenomycin-minimal PKS genes and an ARO/CYC activity had been overexpressed produced tetracenomycin F2, a precursor to the natural product tetracenomycin A (the remainder of the pathway is indicated by dashed arrows). The same result has been achieved using purified proteins in vitro.

HC Gramajo, J White, CR Hutchinson, MJ Bibb. Overproduction and localization of components of the polyketide synthase of Streptomyces glaucescens involved in the production ofthe antibiotic tetracenomycin C. JBacteriol 173 6475-6483,1991. 

B Shen, RG Summers, H Gramajo, MJ Bibb, CR Hutchinson. Purification and characterization of the acyl carrier protein of the Streptomyces glaucescens tetracenomycin C polyketide synthase. JBacteriol 174 3818-3821, 1992. 

B Shen, RG Summers, E Wendt-Pienkowski, CR Hutchinson. The Streptomyces glaucescens TcmKL polyketide synthase and TcmN polyketide cyclase genes govern the size and shape of aromatic polyketides. J Am Chem Soc 117 6811-6821, 1995. 

Huber, M. and Lerch, K. (1988). Identification of two histidines as copper ligands in Streptomyces glaucescens tyrosinase. Biochemistry, 27, 5610-5615. 

SUMMERS, R.G., WENDT-PIENKOWSKI, E., MOTAMEDI, H HUTCHINSON, C.R., Nucleotide sequence of the tcmll-tcmlV region of the tetracenomycin C biosynthetic gene cluster of Streptomyces glaucescens and evidence that the tcmN gene encodes a multifunctional cyclase-dehydratase-O-methyl transferase, J. Bacteriol., 1992,174, 1810-1820. 

Depending on the somce of the enzyme, the Mr s vary between 29 000 and 450 000 with subunit Mr s from 29 000 to 67 000. To date, the enzyme from the bacterium Streptomyces glaucescens was found to have the smallest functional unit with one copper pair per polypeptide chain of 29000. Ty s from microorganisms and plants are generally present as soluble proteins in contrast, those from mammals are bound to specific organelles (melanosomes) in cells termed melanocytes. 

In 1986, Keller-Schierlein, ZShner and their respective coworkers isolated ( )-differolide (135, Figure 5.14) from cultures of an actinomycete, Streptomyces aurantiogriseus Tii 3149. This compound ( )-135, whose structure was determined by X-ray diffraction studies, was reported to enhance the formation of aerial mycelium and spores of Streptomyces glaucescens. Especially noteworthy was the fact that the natural product was racemic. There are some examples of the occurrence of racemic and bioactive natural products such as magnosalicin (10) and olean (116), but they are rare. Although there was a straightforward Diels-Alder synthesis of ( )-135 by dimerization of 2-vinyl-2-buten-4-olide, this method would not afford the enantiomers of 135. 

Motamedi, H. and C.R. Hutchinson (1987). Cloning and heterologous expression of a gene cluster for the biosynthesis of tetracenomycin C, the anthracycline antitumor antibiotic of Streptomyces glaucescens. Proc Natl Acad Sci U S A 84 4445-4449. 

Summers, R.G., E. Wendt-Pienkowsky, H. Motamedi, C.R. Hutchinson, CR. 1993. The tcmVI region of the tetracenomycin C biosynthetic gene duster of Streptomyces glaucescens encodes the tetracenomycin FI monooxygenase, tetracenomycin F2 cyclase, and most likely, a second cyclase. J. Bacteriol. 175 7571-7580. 

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