A comparison of the clavam biosynthetic gene clusters in Streptomyces antibioticus Tü1718 and Streptomyces clavuligerus

2012 ◽  
Vol 58 (4) ◽  
pp. 413-425 ◽  
Author(s):  
Sarah Goomeshi Nobary ◽  
Susan E. Jensen

The production of clavam metabolites has been studied previously in Streptomyces clavuligerus , a species that produces clavulanic acid as well as 4 other clavam compounds, but the late steps of the pathway leading to the specific end products are unclear. The present study compared the clavam biosynthetic gene cluster in Streptomyces antibioticus , chosen because it produces only 2 clavam metabolites and no clavulanic acid, with that of S. clavuligerus. A cosmid library of S. antibioticus genomic DNA was screened with a clavaminate synthase-specific probe based on the corresponding genes from S. clavuligerus, and 1 of the hybridizing cosmids was sequenced in full. A clavam gene cluster was identified that shows similarities to that of S. clavuligerus but also contains a number of novel genes. Knock-out mutation of the clavaminate synthase gene abolished clavam production in S. antibioticus, confirming the identity of the gene cluster. Knock-out mutation of a novel gene encoding an apparent oxidoreductase also abolished clavam production. A potential clavam biosynthetic pathway consistent with the genes in the cluster and the metabolites produced by S. antibioticus, and correspondingly different from that of S. clavuligerus, is proposed.

2021 ◽  
Vol 85 (3) ◽  
pp. 714-721
Author(s):  
Risa Takao ◽  
Katsuyuki Sakai ◽  
Hiroyuki Koshino ◽  
Hiroyuki Osada ◽  
Shunji Takahashi

ABSTRACT Recent advances in genome sequencing have revealed a variety of secondary metabolite biosynthetic gene clusters in actinomycetes. Understanding the biosynthetic mechanism controlling secondary metabolite production is important for utilizing these gene clusters. In this study, we focused on the kinanthraquinone biosynthetic gene cluster, which has not been identified yet in Streptomyces sp. SN-593. Based on chemical structure, 5 type II polyketide synthase gene clusters were listed from the genome sequence of Streptomyces sp. SN-593. Among them, a candidate gene cluster was selected by comparing the gene organization with grincamycin, which is synthesized through an intermediate similar to kinanthraquinone. We initially utilized a BAC library for subcloning the kiq gene cluster, performed heterologous expression in Streptomyces lividans TK23, and identified the production of kinanthraquinone and kinanthraquinone B. We also found that heterologous expression of kiqA, which belongs to the DNA-binding response regulator OmpR family, dramatically enhanced the production of kinanthraquinones.


Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 758
Author(s):  
Xiaohe Jin ◽  
Yunlong Zhang ◽  
Ran Zhang ◽  
Kathy-Uyen Nguyen ◽  
Jonathan S. Lindsey ◽  
...  

Tolyporphins A–R are unusual tetrapyrrole macrocycles produced by the non-axenic filamentous cyanobacterium HT-58-2. A putative biosynthetic gene cluster for biosynthesis of tolyporphins (here termed BGC-1) was previously identified in the genome of HT-58-2. Here, homology searching of BGC-1 in HT-58-2 led to identification of similar BGCs in seven other filamentous cyanobacteria, including strains Nostoc sp. 106C, Nostoc sp. RF31YmG, Nostoc sp. FACHB-892, Brasilonema octagenarum UFV-OR1, Brasilonema octagenarum UFV-E1, Brasilonema sennae CENA114 and Oculatella sp. LEGE 06141, suggesting their potential for tolyporphins production. A similar gene cluster (BGC-2) also was identified unexpectedly in HT-58-2. Tolyporphins BGCs were not identified in unicellular cyanobacteria. Phylogenetic analysis based on 16S rRNA and a common component of the BGCs, TolD, points to a close evolutionary history between each strain and their respective tolyporphins BGC. Though identified with putative tolyporphins BGCs, examination of pigments extracted from three cyanobacteria has not revealed the presence of tolyporphins. Overall, the identification of BGCs and potential producers of tolyporphins presents a collection of candidate cyanobacteria for genetic and biochemical analysis pertaining to these unusual tetrapyrrole macrocycles.


Author(s):  
Rebecca Devine ◽  
Hannah McDonald ◽  
Zhiwei Qin ◽  
Corinne Arnold ◽  
Katie Noble ◽  
...  

AbstractThe formicamycins are promising antibiotics with potent activity against Gram-positive pathogens including VRE and MRSA and display a high barrier to selection of resistant isolates. They were first identified in Streptomyces formicae KY5, which produces the formicamycins at low levels on solid agar but not in liquid culture, thus hindering further investigation of these promising antibacterial compounds. We hypothesised that by understanding the organisation and regulation of the for biosynthetic gene cluster, we could rationally refactor the cluster to increase production levels. Here we report that the for biosynthetic gene cluster consists of 24 genes expressed on nine transcripts. Seven of these transcripts, including those containing all the major biosynthetic genes, are repressed by the MarR-regulator ForJ which also controls the expression of the ForGF two-component system that initiates biosynthesis. A third cluster-situated regulator, ForZ, autoregulates and controls production of the putative MFS transporter ForAA. Consistent with these findings, deletion of forJ increased formicamycin biosynthesis 5-fold, while over-expression of forGF in the ΔforJ background increased production 10-fold compared to the wild-type. De-repression by deleting forJ also switched on biosynthesis in liquid-culture and induced the production of two novel formicamycin congeners. By combining mutations in regulatory and biosynthetic genes, six new biosynthetic precursors with antibacterial activity were also isolated. This work demonstrates the power of synthetic biology for the rational redesign of antibiotic biosynthetic gene clusters both to engineer strains suitable for fermentation in large scale bioreactors and to generate new molecules.ImportanceAntimicrobial resistance is a growing threat as existing antibiotics become increasingly ineffective against drug resistant pathogens. Here we determine the transcriptional organisation and regulation of the gene cluster encoding biosynthesis of the formicamycins, promising new antibiotics with activity against drug resistant bacteria. By exploiting this knowledge, we construct stable mutant strains which over-produce these molecules in both liquid and solid culture whilst also making some new compound variants. This will facilitate large scale purification of these molecules for further study including in vivo experiments and the elucidation of their mechanism of action. Our work demonstrates that understanding the regulation of natural product biosynthetic pathways can enable rational improvement of the producing strains.


2004 ◽  
Vol 70 (11) ◽  
pp. 6353-6362 ◽  
Author(s):  
Michelle C. Moffitt ◽  
Brett A. Neilan

ABSTRACT Nodularia spumigena is a bloom-forming cyanobacterium which produces the hepatotoxin nodularin. The complete gene cluster encoding the enzymatic machinery required for the biosynthesis of nodularin in N. spumigena strain NSOR10 was sequenced and characterized. The 48-kb gene cluster consists of nine open reading frames (ORFs), ndaA to ndaI, which are transcribed from a bidirectional regulatory promoter region and encode nonribosomal peptide synthetase modules, polyketide synthase modules, and tailoring enzymes. The ORFs flanking the nda gene cluster in the genome of N. spumigena strain NSOR10 were identified, and one of them was found to encode a protein with homology to previously characterized transposases. Putative transposases are also associated with the structurally related microcystin synthetase (mcy) gene clusters derived from three cyanobacterial strains, indicating a possible mechanism for the distribution of these biosynthetic gene clusters between various cyanobacterial genera. We propose an alternative hypothesis for hepatotoxin evolution in cyanobacteria based on the results of comparative and phylogenetic analyses of the nda and mcy gene clusters. These analyses suggested that nodularin synthetase evolved from a microcystin synthetase progenitor. The identification of the nodularin biosynthetic gene cluster and evolution of hepatotoxicity in cyanobacteria reported in this study may be valuable for future studies on toxic cyanobacterial bloom formation. In addition, an appreciation of the natural evolution of nonribosomal biosynthetic pathways will be vital for future combinatorial engineering and rational design of novel metabolites and pharmaceuticals.


2007 ◽  
Vol 52 (2) ◽  
pp. 574-585 ◽  
Author(s):  
Xiujun Zhang ◽  
Lawrence B. Alemany ◽  
Hans-Peter Fiedler ◽  
Michael Goodfellow ◽  
Ronald J. Parry

ABSTRACT The antibiotics lactonamycin and lactonamycin Z provide attractive leads for antibacterial drug development. Both antibiotics contain a novel aglycone core called lactonamycinone. To gain insight into lactonamycinone biosynthesis, cloning and precursor incorporation experiments were undertaken. The lactonamycin gene cluster was initially cloned from Streptomyces rishiriensis. Sequencing of ca. 61 kb of S. rishiriensis DNA revealed the presence of 57 open reading frames. These included genes coding for the biosynthesis of l-rhodinose, the sugar found in lactonamycin, and genes similar to those in the tetracenomycin biosynthetic gene cluster. Since lactonamycin production by S. rishiriensis could not be sustained, additional proof for the identity of the S. rishiriensis cluster was obtained by cloning the lactonamycin Z gene cluster from Streptomyces sanglieri. Partial sequencing of the S. sanglieri cluster revealed 15 genes that exhibited a very high degree of similarity to genes within the lactonamycin cluster, as well as an identical organization. Double-crossover disruption of one gene in the S. sanglieri cluster abolished lactonamycin Z production, and production was restored by complementation. These results confirm the identity of the genetic locus cloned from S. sanglieri and indicate that the highly similar locus in S. rishiriensis encodes lactonamycin biosynthetic genes. Precursor incorporation experiments with S. sanglieri revealed that lactonamycinone is biosynthesized in an unusual manner whereby glycine or a glycine derivative serves as a starter unit that is extended by nine acetate units. Analysis of the gene clusters and of the precursor incorporation data suggested a hypothetical scheme for lactonamycinone biosynthesis.


2000 ◽  
Vol 182 (14) ◽  
pp. 4087-4095 ◽  
Author(s):  
Rongfeng Li ◽  
Nusrat Khaleeli ◽  
Craig A. Townsend

ABSTRACT Clavulanic acid is a potent inhibitor of β-lactamase enzymes and is of demonstrated value in the treatment of infections by β-lactam-resistant bacteria. Previously, it was thought that eight contiguous genes within the genome of the producing strainStreptomyces clavuligerus were sufficient for clavulanic acid biosynthesis, because they allowed production of the antibiotic in a heterologous host (K. A. Aidoo, A. S. Paradkar, D. C. Alexander, and S. E. Jensen, p. 219–236, In V. P. Gullo et al., ed., Development in industrial microbiology series, 1993). In contrast, we report the identification of three new genes, orf10 (cyp), orf11(fd), and orf12, that are required for clavulanic acid biosynthesis as indicated by gene replacement andtrans-complementation analysis in S. clavuligerus. These genes are contained within a 3.4-kb DNA fragment located directly downstream of orf9(cad) in the clavulanic acid cluster. While theorf10 (cyp) and orf11(fd) proteins show homologies to other knownCYP-150 cytochrome P-450 and [3Fe-4S] ferredoxin enzymes and may be responsible for an oxidative reaction late in the pathway, the protein encoded by orf12 shows no significant similarity to any known protein. The results of this study extend the biosynthetic gene cluster for clavulanic acid and attest to the importance of analyzing biosynthetic genes in the context of their natural host. Potential functional roles for these proteins are proposed.


2009 ◽  
Vol 76 (1) ◽  
pp. 283-293 ◽  
Author(s):  
Hanne Jørgensen ◽  
Kristin F. Degnes ◽  
Alexander Dikiy ◽  
Espen Fjærvik ◽  
Geir Klinkenberg ◽  
...  

ABSTRACT A new compound, designated ML-449, structurally similar to the known 20-membered macrolactam BE-14106, was isolated from a marine sediment-derived Streptomyces sp. Cloning and sequencing of the 83-kb ML-449 biosynthetic gene cluster revealed its high level of similarity to the BE-14106 gene cluster. Comparison of the respective biosynthetic pathways indicated that the difference in the compounds' structures stems from the incorporation of one extra acetate unit during the synthesis of the acyl side chain. A phylogenetic analysis of the β-ketosynthase (KS) domains from polyketide synthases involved in the biosynthesis of macrolactams pointed to a common ancestry for the two clusters. Furthermore, the analysis demonstrated the formation of a macrolactam-specific subclade for the majority of the KS domains from several macrolactam-biosynthetic gene clusters, indicating a closer relationship between macrolactam clusters than with the macrolactone clusters included in the analysis. Some KS domains from the ML-449, BE-14106, and salinilactam gene clusters did, however, show a closer relationship with KS domains from the polyene macrolide clusters, suggesting potential acquisition rather than duplication of certain PKS genes. Comparison of the ML-449, BE-14106, vicenistatin, and salinilactam biosynthetic gene clusters indicated an evolutionary relationship between them and provided new insights into the processes governing the evolution of small-ring macrolactam biosynthesis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yaqi Wang ◽  
Wei Cao ◽  
Justin Merritt ◽  
Zhoujie Xie ◽  
Hao Liu

FtsH belongs to the AAA+ ATP-dependent family of proteases, which participate in diverse cellular processes and are ubiquitous among bacteria, chloroplasts, and mitochondria. FtsH is poorly characterized in most organisms, especially compared to other major housekeeping proteases. In the current study, we examined the source of FtsH essentiality in the human oral microbiome species Streptococcus mutans, one of the primary etiological agents of dental caries. By creating a conditionally lethal ftsH mutant, we were able to identify a secondary suppressor missense mutation in the vicR gene, encoding the response regulator of the essential VicRK two-component system (TCS). Transcriptomic analysis of the vicR (G195R) mutant revealed significantly reduced expression of 46 genes, many of which were located within the genomic island Tnsmu2, which harbors the mutanobactin biosynthetic gene cluster. In agreement with the transcriptomic data, deletion of the mutanobactin biosynthetic gene cluster suppressed ftsH essentiality in S. mutans. We also explored the role of FtsH in S. mutans physiology and demonstrated its critical role in stress tolerance, especially acid stress. The presented results reveal the first insights within S. mutans for the pleiotropic regulatory function of this poorly understood global regulator.


Marine Drugs ◽  
2019 ◽  
Vol 17 (7) ◽  
pp. 388 ◽  
Author(s):  
Li Liao ◽  
Shiyuan Su ◽  
Bin Zhao ◽  
Chengqi Fan ◽  
Jin Zhang ◽  
...  

Rare actinobacterial species are considered as potential resources of new natural products. Marisediminicola antarctica ZS314T is the only type strain of the novel actinobacterial genus Marisediminicola isolated from intertidal sediments in East Antarctica. The strain ZS314T was able to produce reddish orange pigments at low temperatures, showing characteristics of carotenoids. To understand the biosynthetic potential of this strain, the genome was completely sequenced for data mining. The complete genome had 3,352,609 base pairs (bp), much smaller than most genomes of actinomycetes. Five biosynthetic gene clusters (BGCs) were predicted in the genome, including a gene cluster responsible for the biosynthesis of C50 carotenoid, and four additional BGCs of unknown oligosaccharide, salinixanthin, alkylresorcinol derivatives, and NRPS (non-ribosomal peptide synthetase) or amino acid-derived compounds. Further experimental characterization indicated that the strain may produce C.p.450-like carotenoids, supporting the genomic data analysis. A new xanthorhodopsin gene was discovered along with the analysis of the salinixanthin biosynthetic gene cluster. Since little is known about this genus, this work improves our understanding of its biosynthetic potential and provides opportunities for further investigation of natural products and strategies for adaptation to the extreme Antarctic environment.


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