Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• second ketosynthase of the polyketide synthase BaeJ involved in bacillaene biosynthesis (BaeJ-KS2). For this purpose, both enantiomers of a 13C-labelled N-acetylcysteamine thioester (SNAC ester) surrogate of the proposed natural intermediate of BaeJ-KS2 were synthesised, including an enzymatic step with

• glutamate decarboxylase, and incubated with BaeJ-KS2. Substrate binding was demonstrated through 13C NMR analysis of the products against the background of various control experiments. Keywords: bacillaene; biosynthesis; enzyme mechanisms; isotopes; trans-AT polyketide synthases; Introduction Polyketides

• understanding of polyketide biosynthesis has been reached, including a detailed knowledge of the extender unit selection and the stereochemical implications that are predictable from amino acid sequences [5][6]. The polyene antibiotic bacillaene was first isolated from Bacillus subtilis [7]. This soil-dwelling

Secondary metabolites of Bacillus subtilis impact the assembly of soil-derived semisynthetic bacterial communities

• Heiko T. Kiesewalter,
• Carlos N. Lozano-Andrade,
• Mikael L. Strube and
• Ákos T. Kovács

Beilstein J. Org. Chem. 2020, 16, 2983–2998, doi:10.3762/bjoc.16.248

• soil-derived semisynthetic mock communities containing 13 main genera and supplemented them with B. subtilis P5_B1 WT, the NRP-deficient strain sfp, or single-NRP mutants incapable of producing surfactin, plipastatin, or bacillaene. Through 16S amplicon sequencing, it was revealed that the invasion of

• synthesised by NRPS gene clusters (surfactin, plipastatin, and bacillibactin) and one by a hybrid NRPS–PKS gene cluster (bacillaene, Figure 1). The well-studied biosurfactant surfactin, encoded by the srfAA-AD gene cluster, reduces the surface tension needed for swarming and sliding motility [38][39]. The

• primarily against various filamentous fungi [47][48][49][50][51]. The broad-spectrum antibiotic bacillaene, synthesised by the pksB-S gene cluster, is mainly targeting bacterial protein synthesis [52]. Still, it was also shown that it could protect cells and spores from predation [53]. We recently

A non-canonical peptide synthetase adenylates 3-methyl-2-oxovaleric acid for auriculamide biosynthesis

• Daniel Braga,
• Dirk Hoffmeister and
• Markus Nett

Beilstein J. Org. Chem. 2016, 12, 2766–2770, doi:10.3762/bjoc.12.274

• being tethered to the PCP domain by the PKS-type ketoreductase domain (KR), as reported for other natural products, such as pyridomycin [11], cereulide, valinomycin [12], and bacillaene [13]. Hence, the molecule to be recognized and activated by AulA would be 3-methyl-2-oxovaleric acid (3). Seminal work

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• fungus-growing termite Macrotermes natalensis harbors a Bacillus strain, which produces a single major antibiotic, bacillaene A (15) (Figure 5), that inhibits putatively competitive or antagonistic fungi of Termitomyces suggesting a defensive property [93]. In various other studies, Streptomyces have

• ), antimycin A1 (10), pseudonocardone B (11), mycangimycin (12), frontalamide A (13), frontalamide B (14), and bacillaene A (15). Secondary metabolites isolated from Actinobacteria from fungus-growing termites. Microtermolide A (16), microtermolide B (17), natalamycin A (18), 19-S-methylgeldanamycin (19), and