A new cannabigerolic acid derivative and its unprenylated precursor produced through the reconstitution of cannabinoid biosynthesis in Streptomyces.

A new derivative of cannabigerolic acid, designated as iso-cannabigerolic acid (iso-CBGA), a member of the cannabinoid family, and its precursor iso-olivetolic acid (iso-OA) were discovered from the culture of the engineered Streptomyces avermitilis heterologously expressing the genes responsible for cannabigerolic acid biosynthesis. Structural determination revealed an iso-pentyl moiety, which may arise from the biosynthetic precursor pool present in S. avermitilis.

Cytochrome P450 2J2 is required for the natural compound austocystin D to elicit cancer cell toxicity.

Austocystin D is a natural compound that induces cytochrome P450 (CYP) monooxygenase-dependent DNA damage and growth inhibition in certain cancer cell lines. Cancer cells exhibiting higher sensitivity to austocystin D often display elevated CYP2J2 expression. However, the essentiality and the role of CYP2J2 for the cytotoxicity of this compound remain unclear.

Isolation and Structure Elucidation of JBIR-157, a Skeletally Novel Aromatic Polyketide Produced by the Heterologous Expression of a Cryptic Gene Cluster.

Heterologous expression of natural compound biosynthetic gene clusters (BGCs) is a robust approach for not only revealing the biosynthetic mechanisms leading to the compounds, but also for discovering new products from uncharacterized BGCs. We established a heterologous expression technique applicable to huge biosynthetic gene clusters for generating large molecular secondary metabolites such as type-I polyketides. As an example, we targeted concanamycin BGC from Streptomyces neyagawaensis IFO13477 (the cluster size of 99 kbp), and obtained a bacterial artificial chromosome (BAC) clone with an insert size of 211 kbp that contains the entire concanamycin BGC.

Identification of the Cirratiomycin Biosynthesis Gene Cluster in Streptomyces Cirratus: Elucidation of the Biosynthetic Pathways for 2,3-Diaminobutyric Acid and Hydroxymethylserine.

Cirratiomycin, a heptapeptide with antibacterial activity, was isolated and characterized in 1981; however, its biosynthetic pathway has not been elucidated. It contains several interesting nonproteinogenic amino acids, such as (2S,3S)-2,3-diaminobutyric acid ((2S,3S)-DABA) and α-(hydroxymethyl)serine, as building blocks. Here, we report the identification of a cirratiomycin biosynthetic gene cluster in Streptomyces cirratus.

In Vitro Module Editing Of NRPS Enables Production Of Highly Potent G -Signaling Inhibitor FR900359 Derived From Unculturable Plant Symbiont.

Heterotrimeric G proteins are key mediators in the signaling of G protein-coupled receptors (GPCR) that are involved in a plethora of important physiological processes and thus major targets of pharmaceutical drugs. The cyclic depsipeptides YM-254890 and FR900359 are strong and selective inhibitors of the G subfamily of G proteins. FR900359 was first reported to be produced by unculturable plant symbiont, however, a culturable FR900359 producer was discovered recently by the standard strategy, screening of the producing strain from the environment.

Notch activator cyclopiazonic acid induces apoptosis in HL-60 cells through calcineurin activation.

We screened a library of microbial extracts and compounds library using our constructed assay cells and found pulicatins F (1) and G (2), and cyclopiazonic acid (CPA) (3) as Notch activators. Pulicatin F (1) and (±)-pulicatin G were synthesized and their activities were evaluated. Notch activation of CPA (3) was investigated using Western blot and RT-PCR.

Identification of compounds that preferentially suppress the growth of T-cell acute lymphoblastic leukemia-derived cells.

T-cell acute lymphoblastic leukemia (T-ALL) is one of the most frequently occurring cancers in children and is associated with a poor prognosis. Here, we performed large-scale screening of natural compound libraries to identify potential drugs against T-ALL. We identified three low-molecular-weight compounds (auxarconjugatin-B, rumbrin, and lavendamycin) that inhibited the proliferation of the T-ALL cell line CCRF-CEM, but not that of the B lymphoma cell line Raji in a low concentration range.

Identification of small-molecule inhibitors against the interaction of RNA-binding protein PSF and its target RNA for cancer treatment.

Diverse cellular activities are modulated through a variety of RNAs, including long noncoding RNAs (lncRNAs), by binding to certain proteins. The inhibition of oncogenic proteins or RNAs is expected to suppress cancer cell proliferation. We have previously demonstrated that PSF interaction with its target RNAs, such as androgen-induced lncRNA , is critical for hormone therapy resistance in prostate and breast cancers.

Carrier Protein Mediated Formation of the Dihydropyridazinone Ring in Actinopyridazinone Biosynthesis.

Heterocycles with nitrogen-nitrogen (N-N) bonds are privileged building blocks of synthetic drugs. They are also found in natural products, although the biosynthetic logic behind them is poorly understood. Actinopyridazinones produced by Streptomyces sp.

Acyltransferase Domain Exchange between Two Independent Type I Polyketide Synthases in the Same Producer Strain of Macrolide Antibiotics.

Streptomyces graminofaciens A-8890 produces two macrolide antibiotics, FD-891 and virustomycin A, both of which show significant biological activity. In this study, we identified the virustomycin A biosynthetic gene cluster, which encodes type I polyketide synthases (PKSs), ethylmalonyl-CoA biosynthetic enzymes, methoxymalony-acyl carrier protein biosynthetic enzymes, and post-PKS modification enzymes. Next, we demonstrated that the acyltransferase domain can be exchanged between the Vsm PKSs and the PKSs involved in FD-891 biosynthesis (Gfs PKSs), without any supply problems of the unique extender units.

Mechanism of -Adenosyl-l-methionine -Methylation by Cobalamin-dependent Radical -Adenosyl-l-methionine Methylase in 1-Amino-2-methylcyclopropanecarboxylic Acid Biosynthesis.

The radical -adenosyl-l-methionine (SAM) methylase Orf29 catalyzes the -methylation of SAM in the biosynthesis of 1-amino-2-methylcyclopropanecarboxylic acid. Here, we determined that the methylation product is (4″)-4″-methyl-SAM. Furthermore, we found that the 5'-deoxyadenosyl radical generated by Orf29 abstracts the hydrogen atom from the C-4″ position of SAM to generate the radical intermediate, which reacts with methylcobalamin to give (4″)-4″-methyl-SAM.

Bacterial Avenalumic Acid Biosynthesis Includes Substitution of an Aromatic Amino Group for Hydride by Nitrous Acid Dependent Diazotization.

The diazo group is an important functional group that can confer biological activity to natural products owing to its high reactivity. Recent studies have revealed that diazo groups are synthesized from amino groups using nitrous acid in secondary metabolites of actinomycetes. However, genome database analysis indicated that there are still many diazo group-biosynthesizing enzymes for unknown biosynthetic pathways.

New azodyrecins identified by a genome mining-directed reactivity-based screening.

Only a few azoxy natural products have been identified despite their intriguing biological activities. Azodyrecins D-G, four new analogs of aliphatic azoxides, were identified from two species by a reactivity-based screening that targets azoxy bonds. A biological activity evaluation demonstrated that the double bond in the alkyl side chain is important for the cytotoxicity of azodyrecins.

A Natural Dihydropyridazinone Scaffold Generated from a Unique Substrate for a Hydrazine-Forming Enzyme.

Nitrogen-nitrogen bond-containing functional groups are rare, but they are found in a considerably wide class of natural products. Recent clarifications of the biosynthetic routes for such functional groups shed light onto overlooked biosynthetic genes distributed across the bacterial kingdom, highlighting the presence of yet-to-be identified natural products with peculiar functional groups. Here, the genome-mining approach targeting a unique hydrazine-forming gene led to the discovery of actinopyridazinones A () and B (), the first natural products with dihydropyridazinone rings.

Visualization of the dynamic interaction between nucleosomal histone H3K9 tri-methylation and HP1α chromodomain in living cells.

Histone lysine methylation is an epigenetic mark that can control gene expression. In particular, H3K9me3 contributes to transcriptional repression by regulating chromatin structure. Successful mitotic progression requires correct timing of chromatin structure changes, including epigenetic marks.

Stable G-quadruplex DNA structures promote replication-dependent genome instability.

G-quadruplex (G4)-prone structures are abundant in mammalian genomes, where they have been shown to influence DNA replication, transcription, and genome stability. In this article, we constructed cells with a single ectopic homopurine/homopyrimidine repeat tract derived from the polycystic kidney disease type 1 (PKD1) locus, which is capable of forming triplex (H3) and G4 DNA structures. We show that ligand stabilization of these G4 structures results in deletions of the G4 consensus sequence, as well as kilobase deletions spanning the G4 and ectopic sites.

Structural Basis for the Prenylation Reaction of Carbazole-Containing Natural Products Catalyzed by Squalene Synthase-Like Enzymes.

Some enzymes annotated as squalene synthase catalyze the prenylation of carbazole-3,4-quinone-containing substrates in bacterial secondary metabolism. Their reaction mechanisms remain unclear because of their low sequence similarity to well-characterized aromatic substrate prenyltransferases (PTs). We determined the crystal structures of the carbazole PTs, and these revealed that the overall structure is well superposed on those of squalene synthases.

Complete Genome Sequence of sp. Strain TBR-22.

We report a complete genome sequence of a novel bacterial isolate, strain TBR-22, belonging to the class of the phylum , which was isolated from duckweed fronds. The genome expands our knowledge of the lifestyle of this abundant but rarely characterized phylum.

Draft Genome Sequence of Strain F-183.

Here, we report a draft genome sequence of a bacterial strain, F-183, isolated from a duckweed frond. Strain F-183 belongs to the family of the phylum , and its genomic information would contribute to understanding the ecophysiology of this abundant but rarely characterized phylum.

Structural and Molecular Basis of the Catalytic Mechanism of Geranyl Pyrophosphate C6-Methyltransferase: Creation of an Unprecedented Farnesyl Pyrophosphate C6-Methyltransferase.

Prenyl pyrophosphate methyltransferases enhance the structural diversity of terpenoids. However, the molecular basis of their catalytic mechanisms is poorly understood. In this study, using multiple strategies, we characterized a geranyl pyrophosphate (GPP) C6-methyltransferase, BezA.

Phenotypic screening system using three-dimensional (3D) culture models for natural product screening.

Recent progress in three-dimensional (3D) cell culture systems has attracted much attention in the fields of basic life science and drug development. Newly established methods include 3D co-culture, spheroid culture, and organoid culture; these methods enable more human tissue-like culture and have largely replaced traditional two-dimensional (2D) monolayer culture. By combining 3D culture methods with high-content imaging analysis, it is possible to obtain diverse and convincing data even during initial screening (which requires rapid and easy operating procedures).

Chemical targeting of G-quadruplexes in telomeres and beyond for molecular cancer therapeutics.

G-quadruplexes (G4s) are higher-order structures formed by guanine-rich sequences of nucleic acids, such as the telomeric 5'-TTAGGG-3'/5'-UUAGGG-3' repeats and those in gene regulatory regions. G4s regulate various biological events, including replication, transcription, and translation. Imbalanced G4 dynamics is associated with diseases, such as cancer and neurodegenerative diseases.