Mutational analysis of a phenazine biosynthetic gene cluster in Streptomyces anulatus 9663

• Orwah Saleh,
• Katrin Flinspach,
• Lucia Westrich,
• Andreas Kulik,
• Bertolt Gust,
• Hans-Peter Fiedler and
• Lutz Heide

Beilstein J. Org. Chem. 2012, 8, 501–513, doi:10.3762/bjoc.8.57

• similar N-acetylcysteine adduct has been described for a polyketide antibiotic, also leading to a loss of biological activity; therefore, the conjugation has been suggested as representing a detoxification mechanism [18]. The extent of the conversion of endophenazine A to endophenazine E in cultures of S

• napyradiomycin biosynthesis gene cluster from S. aculeolatus [30], and fur18 in the biosynthetic gene cluster of furaquinocin A from Streptomyces sp. KO-3988 [31]. A similar gene, aur1O, is found in the biosynthetic gene cluster of the polyketide antibiotic auricin from S. aureofaciens [32]. The function of

Aldol elaboration of 4,5,6,7-tetrahydroisoxazolo[4,3-c]pyridin-4-ones, masked precursors to acylpyridones

• Raymond C. F. Jones,
• Abdul K. Choudhury,
• James N. Iley,
• Mark E. Light,
• Georgia Loizou and
• Terence A. Pillainayagam

Beilstein J. Org. Chem. 2012, 8, 308–312, doi:10.3762/bjoc.8.33

• product ilicicolin H (9) (Figure 3) [20][21] along with fischerin, apiosporamide and YM-215343, displays a 3-decalinoyl-4-hydroxypyridin-2-one skeleton wherein the decalin unit may arise biosynthetically from a Diels–Alder reaction within the polyketide-derived side chain [1][22]. As a further

Novel fatty acid methyl esters from the actinomycete Micromonospora aurantiaca

• Jeroen S. Dickschat,
• Hilke Bruns and
• Ramona Riclea

Beilstein J. Org. Chem. 2011, 7, 1697–1712, doi:10.3762/bjoc.7.200

• elongation units, and occur due to the logic of FA biosynthesis in even-numbered positions of the FA carbon chain. An alternative mechanism leading to the same methyl branching pattern is well-known from polyketide biosynthesis and involves the incorporation of a malonyl-CoA unit followed by SAM-dependent

• methylation of the new α-carbon. Further alternative starters are known [2][3][4], but these cases are rare. In contrast, the usage of alternative elongation units such as ethylmalonyl-CoA [5], propylmalonyl-CoA [6], isobutylmalonyl-CoA [7], or methoxymalonyl-ACP [8] remains almost limited to polyketide

Marilones A–C, phthalides from the sponge-derived fungus Stachylidium sp.

• Celso Almeida,
• Stefan Kehraus,
• Miguel Prudêncio and
• Gabriele M. König

Beilstein J. Org. Chem. 2011, 7, 1636–1642, doi:10.3762/bjoc.7.192

• the polyketide metabolism, which are common in nature [1]. Secondary metabolites 1 and 2 discovered in the marine-derived Stachylidium sp. were found to be derivatives of the natural product nidulol, whilst compound 3 was a derivative of silvaticol (4) (see Supporting Information File 1), formerly

• derivatives 1 and 2 are distinguished by an additional methyl substituent (11-CH3) at C-8. In terms of biosynthesis, i.e., polyketide metabolism, this substitution is most unusual for phthalides and, to the best of our knowledge, it was only found once in dimethoxydimethylphthalide (DDP) [12]. Biosynthetic

• D in Figure S15; Supporting Information File 1). A third possibility would be the loss of a carbon atom from a pentaketide intermediate. To our knowledge, to date propionate as a starter unit was only described for pseurotin A and austrocorticinic acid in fungal polyketide metabolism [15][16

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) pathways and highlight the unique enzyme mechanisms that were elucidated or can be anticipated for the individual products. We further include ribosomal natural products and UV-absorbing pigments from cyanobacteria. Mechanistic insights

• combined with transport across the plasma membrane [12] (Figure 2). Macrolides in microorganisms are produced by modular type polyketide synthases (PKS) resembling NRPS with respect to their modular nature. In contrast to the peptide-synthesizing enzymes, different types of carboxylic acids are activated

• iteratively [16]. Nonribosomal peptide, polyketide and hybrid biosyntheses in cyanobacteria Research on NRPS and PKS gene clusters started almost in parallel in freshwater, marine and terrestrial cyanobacteria. A major trait of cyanobacterial pathways is their hybrid character, i.e., the frequent mixture of

Biosynthesis and function of secondary metabolites

• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2011, 7, 1620–1621, doi:10.3762/bjoc.7.190

• polyketide and nonribosomal peptide biosynthetic machineries, which is strongly correlated with the logic of fatty acid biosynthesis as part of the primary metabolism. Insights into the mechanisms of modular polyketide and nonribosomal peptide assembly lines open up the possibility for direct modifications

Phaeochromycins F–H, three new polyketide metabolites from Streptomyces sp. DSS-18

• Jian Li,
• Chun-Hua Lu,
• Bao-Bing Zhao,
• Zhong-Hui Zheng and
• Yue-Mao Shen

Beilstein J. Org. Chem. 2008, 4, No. 46, doi:10.3762/bjoc.4.46