1.Biosynthesis of diazepinomicin/ECO-4601, a Micromonospora secondary metabolite with a novel ring system.
McAlpine JB1, Banskota AH, Charan RD, Schlingmann G, Zazopoulos E, Piraee M, Janso J, Bernan VS, Aouidate M, Farnet CM, Feng X, Zhao Z, Carter GT. J Nat Prod. 2008 Sep;71(9):1585-90. doi: 10.1021/np800376n. Epub 2008 Aug 23.
The novel microbial metabolite diazepinomicin/ECO-4601 (1) has a unique tricyclic dibenzodiazepinone core, which was unprecedented among microbial metabolites. Labeled feeding experiments indicated that the carbocyclic ring and the ring nitrogen of tryptophan could be incorporated via degradation to the 3-hydroxyanthranilic acid, forming ring A and the nonamide nitrogen of 1. Genomic analysis of the biosynthetic locus indicated that the farnesyl side chain was mevalonate derived, the 3-hydroxyanthranilic acid moiety could be formed directly from chorismate, and the third ring was constructed via 3-amino-5-hydroxybenzoic acid. Successful incorporation of 4,6-D2-3-hydroxyanthranilic acid into ring A of 1 via feeding experiments supports the genetic analysis and the allocation of the locus to this biosynthesis. These studies highlight the enzymatic complexity needed to produce this structural type, which is rare in nature.
2.Unusual N-prenylation in diazepinomicin biosynthesis: the farnesylation of a benzodiazepine substrate is catalyzed by a new member of the ABBA prenyltransferase superfamily.
Bonitz T1, Zubeil F2, Grond S2, Heide L1. PLoS One. 2013 Dec 23;8(12):e85707. doi: 10.1371/journal.pone.0085707. eCollection 2013.
The bacterium Micromonospora sp. RV115, isolated from a marine sponge, produces the unusual metabolite diazepinomicin, a prenylated benzodiazepine derivative. We have cloned the prenyltransferase gene dzmP from this organism, expressed it in Escherichia coli, and the resulting His8-tagged protein was purified and investigated biochemically. It was found to catalyze the farnesylation of the amide nitrogen of dibenzodiazepinone. DzmP belongs to the ABBA prenyltransferases and is the first member of this superfamily which utilizes farnesyl diphosphate as genuine substrate. All previously discovered members utilize either dimethylallyl diphosphate (C5) or geranyl diphosphate (C10). Another putative diazepinomicin biosynthetic gene cluster was identified in the genome of Streptomyces griseoflavus Tü4000, suggesting that the formation of diazepinomicin is not restricted to the genus Micromonospora. The gene cluster contains a gene ssrg_00986 with 61.
3.Antioxidant and anti-protease activities of diazepinomicin from the sponge-associated Micromonospora strain RV115.
Abdelmohsen UR1, Szesny M, Othman EM, Schirmeister T, Grond S, Stopper H, Hentschel U. Mar Drugs. 2012 Oct;10(10):2208-21. doi: 10.3390/md10102208. Epub 2012 Oct 8.
Diazepinomicin is a dibenzodiazepine alkaloid with an unusual structure among the known microbial metabolites discovered so far. Diazepinomicin was isolated from the marine sponge-associated strain Micromonospora sp. RV115 and was identified by spectroscopic analysis and by comparison to literature data. In addition to its interesting preclinical broad-spectrum antitumor potential, we report here new antioxidant and anti-protease activities for this compound. Using the ferric reducing antioxidant power (FRAP) assay, a strong antioxidant potential of diazepinomicin was demonstrated. Moreover, diazepinomicin showed a significant antioxidant and protective capacity from genomic damage induced by the reactive oxygen species hydrogen peroxide in human kidney (HK-2) and human promyelocytic (HL-60) cell lines. Additionally, diazepinomicin inhibited the proteases rhodesain and cathepsin L at an IC₅₀ of 70-90 µM. It also showed antiparasitic activity against trypomastigote forms of Trypanosoma brucei with an IC₅₀ of 13.
4.Evaluating indole-related derivatives as precursors in the directed biosynthesis of diazepinomicin analogues.
Ratnayake AS1, Janso JE, Feng X, Schlingmann G, Goljer I, Carter GT. J Nat Prod. 2009 Mar 27;72(3):496-9. doi: 10.1021/np800664u.
The effectiveness of precursor-directed biosynthesis to generate diazepinomicin (1) analogues with varied ring-A substitutents was investigated by feeding commercially available, potential ring-A precursors such as fluorinated tryptophans, halogenated anthranilates, and various substituted indoles into growing actinomycete culture DPJ15 (genus Micromonospora). Two new monofluorinated diazepinomicin analogues (2 and 3) were identified and characterized by spectroscopic methods. Both derivatives showed modest antibacterial activity against the Gram-positive coccus Staphylococcus aureus with MIC values in the range 8-32 microg/mL.