scholarly journals Two Separate Gene Clusters Encode the Biosynthetic Pathway for the Meroterpenoids Austinol and Dehydroaustinol inAspergillus nidulans

2012 ◽  
Vol 134 (10) ◽  
pp. 4709-4720 ◽  
Author(s):  
Hsien-Chun Lo ◽  
Ruth Entwistle ◽  
Chun-Jun Guo ◽  
Manmeet Ahuja ◽  
Edyta Szewczyk ◽  
...  
mSystems ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Daniela B. B. Trivella ◽  
Rafael de Felicio

ABSTRACT Natural products are the richest source of chemical compounds for drug discovery. Particularly, bacterial secondary metabolites are in the spotlight due to advances in genome sequencing and mining, as well as for the potential of biosynthetic pathway manipulation to awake silent (cryptic) gene clusters under laboratory cultivation. Further progress in compound detection, such as the development of the tandem mass spectrometry (MS/MS) molecular networking approach, has contributed to the discovery of novel bacterial natural products. The latter can be applied directly to bacterial crude extracts for identifying and dereplicating known compounds, therefore assisting the prioritization of extracts containing novel natural products, for example. In our opinion, these three approaches—genome mining, silent pathway induction, and MS-based molecular networking—compose the tripod for modern bacterial natural product discovery and will be discussed in this perspective.


2004 ◽  
Vol 50 (10) ◽  
pp. 803-810 ◽  
Author(s):  
Kapil Tahlan ◽  
Hyeon Ung Park ◽  
Susan E Jensen

In Streptomyces clavuligerus, three groups of genes are known to be involved in the biosynthesis of the clavam metabolites. Since antibiotic biosynthetic genes are invariably clustered on the chromosome in prokaryotes, chromosome walking was undertaken in an attempt to show that the three groups of clavam genes would resolve into a single super-cluster when analyzed at larger scale. However, no evidence of linkage between the three groups was obtained. Furthermore, Southern analysis of macro-restriction fragments of genomic DNA separated by pulsed-field gel electrophoresis also indicated that the three groups of genes are not linked. Despite the structural and biosynthetic relatedness of the clavam metabolites, our results suggest that the genes involved in their production lie in three unlinked gene clusters. We believe that this represents the first instance in bacteria of genes involved in the biosynthesis of a single family of antibiotics sharing a common biosynthetic pathway and yet residing in three separate locations on the chromosome.Key words: Streptomyces, clavulanic acid, clavams, paralogues, gene clusters.


Genetics ◽  
1975 ◽  
Vol 79 (3) ◽  
pp. 361-376
Author(s):  
Caroline Kane-Falce ◽  
Wesley E Kloos

ABSTRACT Histidine auxotrophs of Micrococcus luteus strain ATCC 27141 were induced by treatment of the parent strain with N-methyl-N′-nitro-N-nitro-soguanidine. Auxotrophs were biochemically characterized by examining culture accumulations of histidine intermediates, using paper chromatography and the Bratton-Marshall test, and growth responses to L-histidinol. his(IG) mutants failed to accumulate Pauly-positive imidazoles; his(EAHF) mutants accumulated 5-amino-1-ribosyl-4-imidazole carboxamide; hisB mutants accumulated imidazoleglycerol; hisC mutants accumulated imidazoleacetol; hisD mutants accumulated histidinol. L-histidinol failed to stimulate the growth of hisD mutants, but did stimulate all other histidine mutants, blocked at earlier steps in the biosynthetic pathway. In addition, imidazoleglycerol phosphate dehydrase activity was assayed in representative mutants of each class. hisB mutants lacked activity for this enzyme.—Two-point, three-point, and cotransformation analyses resolved linkage relationships of histidine genes and in two gene clusters aided in determining their sequences. Histidine biosynthetic genes exist in at least four separate, unlinked regions of the chromosome. One histidine gene cluster is closely linked to a tryptophan gene cluster and appears to be contiguous in the sequence his(IG)-his(EAHF)-trpE-trpC-trpB-trpA. A second and unlinked histidine cluster has the tentative gene sequence his(EAHF)-hisB-hisC-his(EAHF). The hisD gene and an unclassified mutant site his-94 are not linked to any of the other histidine genes examined in this study or to each other.


2005 ◽  
Vol 187 (22) ◽  
pp. 7853-7856 ◽  
Author(s):  
Scot P. Ouellette ◽  
Yasser M. AbdelRahman ◽  
Robert J. Belland ◽  
Gerald I. Byrne

ABSTRACT Two chlamydial homologues of the Yersinia lcrH chaperone for type III secretion system structural components are present within separate gene clusters. Quantitative transcriptional analyses demonstrated that each cluster is differentially regulated and expressed as an operon using major sigma factor elements, suggesting the presence of more elaborate developmental regulation mechanisms in chlamydiae.


Archaea ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-15 ◽  
Author(s):  
Sonja Storbeck ◽  
Sarah Rolfes ◽  
Evelyne Raux-Deery ◽  
Martin J. Warren ◽  
Dieter Jahn ◽  
...  

Heme is an essential prosthetic group for many proteins involved in fundamental biological processes in all three domains of life. InEukaryotaandBacteriaheme is formedviaa conserved and well-studied biosynthetic pathway. Surprisingly, inArchaeaheme biosynthesis proceedsviaan alternative route which is poorly understood. In order to formulate a working hypothesis for this novel pathway, we searched 59 completely sequenced archaeal genomes for the presence of gene clusters consisting of established heme biosynthetic genes and colocalized conserved candidate genes. Within the majority of archaeal genomes it was possible to identify such heme biosynthesis gene clusters. From this analysis we have been able to identify several novel heme biosynthesis genes that are restricted to archaea. Intriguingly, several of the encoded proteins display similarity to enzymes involved in hemed1biosynthesis. To initiate an experimental verification of our proposals twoMethanosarcina barkeriproteins predicted to catalyze the initial steps of archaeal heme biosynthesis were recombinantly produced, purified, and their predicted enzymatic functions verified.


2020 ◽  
Author(s):  
Tom H. Eyles ◽  
Natalia M. Vior ◽  
Rodney Lacret ◽  
Andrew W. Truman

ABSTRACTThiostreptamide S4 is a thioamitide, a family of promising antitumour ribosomally synthesised and post-translationally modified peptides (RiPPs). The thioamitides are one of the most structurally complex RiPP families, yet very few thioamitide biosynthetic steps have been elucidated, even though the gene clusters of multiple thioamitides have been identified. We hypothesised that engineering the thiostreptamide S4 gene cluster in a heterologous host could provide insights into its biosynthesis when coupled with untargeted metabolomics and targeted mutations of the precursor peptide. Modified gene clusters were constructed, and in-depth metabolomics enabled a detailed understanding of the biosynthetic pathway, including the identification of an effector-like protein critical for amino acid dehydration. We use this biosynthetic understanding to bioinformatically identify new widespread families of RiPP biosynthetic gene clusters, paving the way for future RiPP discovery and engineering.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Jingyan Zhang ◽  
Ying Sun ◽  
Yeji Wang ◽  
Xin Chen ◽  
Lu Xue ◽  
...  

Abstract Background Rubiginones belong to the angucycline family of aromatic polyketides, and they have been shown to potentiate the vincristine (VCR)-induced cytotoxicity against VCR-resistant cancer cell lines. However, the biosynthetic gene clusters (BGCs) and biosynthetic pathways for rubiginones have not been reported yet. Results In this study, based on bioinformatics analysis of the genome of Streptomyces sp. CB02414, we predicted the functions of the two type II polyketide synthases (PKSs) BGCs. The rub gene cluster was predicted to encode metabolites of the angucycline family. Scale-up fermentation of the CB02414 wild-type strain led to the discovery of eight rubiginones, including five new ones (rubiginones J, K, L, M, and N). Rubiginone J was proposed to be the final product of the rub gene cluster, which features extensive oxidation on the A-ring of the angucycline skeleton. Based on the production profiles of the CB02414 wild-type and the mutant strains, we proposed a biosynthetic pathway for the rubiginones in CB02414. Conclusions A genome mining strategy enabled the efficient discovery of new rubiginones from Streptomyces sp. CB02414. Based on the isolated biosynthetic intermediates, a plausible biosynthetic pathway for the rubiginones was proposed. Our research lays the foundation for further studies on the mechanism of the cytochrome P450-catalyzed oxidation of angucyclines and for the generation of novel angucyclines using combinatorial biosynthesis strategies.


2019 ◽  
Author(s):  
Sylvester Palys ◽  
Thi Thanh My Pham ◽  
Adrian Tsang

AbstractFilamentous fungi are an abundant source of bioactive secondary metabolites (SMs). In many cases, the biosynthetic processes of SMs are not well understood. This work focuses on a group of SMs, the alkylcitric acids, each of which contains a saturated alkyl “tail” and a citrate-derived “head”. We initially identified their biosynthetic gene cluster and the transcriptional regulator (akcR) involved in the biosynthesis of alkylcitrates in the filamentous fungus Aspergillus niger by examining the functional annotation of SM gene clusters predicted from genomic data. We overexpressed the transcription regulator gene akcR and obtained from a litre of culture filtrate 8.5 grams of extract containing seven alkylcitric acids as determined by NMR. Hexylaconitic acid A comprised ~ 95% of the total production, and four of the seven identified alkylcitrates have not been reported previously. Analysis of orthologous alkylcitrate gene clusters in the Aspergilli revealed an in-cluster cis-aconitate decarboxylase gene (cadA) in A. oryzae and A. flavus, which in A. niger is located on a different chromosome. Overexpression of the A. niger cadA and akcR genes together shifted the profile of alkylcitrates production from primarily hexylaconitic acids to mainly hexylitaconic acids. We also detected two additional, previously unreported, alkylcitric acids in the double overexpression strain. This study shows that phylogenomic analysis together with experimental manipulations can be used to reconstruct a more complete biosynthetic pathway in generating a broader spectrum of alkylcitric compounds. The approach adopted here has the potential of elucidating the complexity of other SM biosynthetic pathways in fungi.


Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6580
Author(s):  
Charlotte Beck ◽  
Tetiana Gren ◽  
Francisco Javier Ortiz-López ◽  
Tue Sparholt Jørgensen ◽  
Daniel Carretero-Molina ◽  
...  

Streptomyces are well-known producers of a range of different secondary metabolites, including antibiotics and other bioactive compounds. Recently, it has been demonstrated that “silent” biosynthetic gene clusters (BGCs) can be activated by heterologously expressing transcriptional regulators from other BGCs. Here, we have activated a silent BGC in Streptomyces sp. CA-256286 by overexpression of a set of SARP family transcriptional regulators. The structure of the produced compound was elucidated by NMR and found to be an N-acetyl cysteine adduct of the pyranonaphtoquinone polyketide 3′-O-α-d-forosaminyl-(+)-griseusin A. Employing a combination of multi-omics and metabolic engineering techniques, we identified the responsible BGC. These methods include genome mining, proteomics and transcriptomics analyses, in combination with CRISPR induced gene inactivations and expression of the BGC in a heterologous host strain. This work demonstrates an easy-to-implement workflow of how silent BGCs can be activated, followed by the identification and characterization of the produced compound, the responsible BGC, and hints of its biosynthetic pathway.


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