scholarly journals Zn-dependent bifunctional proteases are responsible for leader peptide processing of class III lanthipeptides

2019 ◽  
Vol 116 (7) ◽  
pp. 2533-2538 ◽  
Author(s):  
Shaoming Chen ◽  
Bing Xu ◽  
Erquan Chen ◽  
Jiaqi Wang ◽  
Jingxia Lu ◽  
...  

Lanthipeptides are an important subfamily of ribosomally synthesized and posttranslationally modified peptides, and the removal of their N-terminal leader peptides by a designated protease(s) is a key step during maturation. Whereas proteases for class I and II lanthipeptides are well-characterized, the identity of the protease(s) responsible for class III leader processing remains unclear. Herein, we report that the class III lanthipeptide NAI-112 employs a bifunctional Zn-dependent protease, AplP, with both endo- and aminopeptidase activities to complete leader peptide removal, which is unprecedented in the biosynthesis of lanthipeptides. AplP displays a broad substrate scope in vitro by processing a number of class III leader peptides. Furthermore, our studies reveal that AplP-like proteases exist in the genomes of all class III lanthipeptide-producing strains but are usually located outside the biosynthetic gene clusters. Biochemical studies show that AplP-like proteases are universally responsible for the leader removal of the corresponding lanthipeptides. In addition, AplP-like proteases are phylogenetically correlated with aminopeptidase N from Escherichia coli, and might employ a single active site to catalyze both endo- and aminopeptidyl hydrolysis. These findings solve the long-standing question as to the mechanism of leader peptide processing during class III lanthipeptide biosynthesis, and pave the way for the production and bioengineering of this class of natural products.

2020 ◽  
Author(s):  
Jingxia Lu ◽  
Yuan Wu ◽  
Jiao Li ◽  
Yuqing Li ◽  
Yingying Zhang ◽  
...  

ABSTRACTThioamitides are a group of ribosomally synthesized and post-translational modified peptides with potent antiproliferative and pro-apoptotic activities. Their biosynthesis remains largely unknown, especially for the characteristic C-terminal 2-aminovinyl-Cysteine (AviCys) motifs. Herein, we report the discovery that homologs of class III lanthipeptide synthetases (LanKCts)encoded outside putative thioamitide biosynthetic gene clusters (BGCs) fully dehydrate the precursor peptides. Remarkably, LanKCt enzymes bind tightly to cysteine decarboxylases encoded inside thioamitide BGCs, and the resulting complex complete the macrocyclization of AviCys rings. Furthermore, LanKCt enzymes are present in the genomes of many thioamitide-producing strains and are functional when in complex with cysteine decarboxylases to produce AviCys macrocycles. Thus, our study reveals the participation of lanthipeptide synthetases as a general strategy for dehydration and AviCys formation during thioamitides biosynthesis and thus paves the way for the bioengineering of this class of bioactive natural products.


2018 ◽  
Vol 200 (21) ◽  
Author(s):  
Karla J. Esquilín-Lebrón ◽  
Tye O. Boynton ◽  
Lawrence J. Shimkets ◽  
Michael G. Thomas

ABSTRACTOne mechanism by which bacteria and fungi produce bioactive natural products is the use of nonribosomal peptide synthetases (NRPSs). Many NRPSs in bacteria require members of the MbtH-like protein (MLP) superfamily for their solubility or function. Although MLPs are known to interact with the adenylation domains of NRPSs, the role MLPs play in NRPS enzymology has yet to be elucidated. MLPs are nearly always encoded within the biosynthetic gene clusters (BGCs) that also code for the NRPSs that interact with the MLP. Here, we identify 50 orphan MLPs from diverse bacteria. An orphan MLP is one that is encoded by a gene that is not directly adjacent to genes predicted to be involved in nonribosomal peptide biosynthesis. We targeted the orphan MLP MXAN_3118 fromMyxococcus xanthusDK1622 for characterization. TheM. xanthusDK1622 genome contains 15 NRPS-encoding BGCs but only one MLP-encoding gene (MXAN_3118). We tested the hypothesis that MXAN_3118 interacts with one or more NRPS using a combination ofin vivoandin vitroassays. We determined that MXAN_3118 interacts with at least seven NRPSs from distinct BGCs. We show that one of these BGCs codes for NRPS enzymology that likely produces a valine-rich natural product that inhibits the clumping ofM. xanthusDK1622 in liquid culture. MXAN_3118 is the first MLP to be identified that naturally interacts with multiple NRPS systems in a single organism. The finding of an MLP that naturally interacts with multiple NRPS systems suggests it may be harnessed as a “universal” MLP for generating functional hybrid NRPSs.IMPORTANCEMbtH-like proteins (MLPs) are essential accessory proteins for the function of many nonribosomal peptide synthetases (NRPSs). We identified 50 MLPs from diverse bacteria that are coded by genes that are not located near any NRPS-encoding biosynthetic gene clusters (BGCs). We define these as orphan MLPs because their NRPS partner(s) is unknown. Investigations into the orphan MLP fromMyxococcus xanthusDK1622 determined that it interacts with NRPSs from at least seven distinct BGCs. Support for these MLP-NRPS interactions came from the use of a bacterial two-hybrid assay and copurification of the MLP with various NRPSs. The flexibility of this MLP to naturally interact with multiple NRPSs led us to hypothesize that this MLP may be used as a “universal” MLP during the construction of functional hybrid NRPSs.


mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Yunkun Liu ◽  
Weixin Tao ◽  
Shishi Wen ◽  
Zhengyuan Li ◽  
Anna Yang ◽  
...  

ABSTRACT The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system, an RNA-guided nuclease for specific genome editing in vivo, has been adopted in a wide variety of organisms. In contrast, the in vitro application of the CRISPR/Cas9 system has rarely been reported. We present here a highly efficient in vitro CRISPR/Cas9-mediated editing (ICE) system that allows specific refactoring of biosynthetic gene clusters in Streptomyces bacteria and other large DNA fragments. Cleavage by Cas9 of circular pUC18 DNA was investigated here as a simple model, revealing that the 3′→5′ exonuclease activity of Cas9 generates errors with 5 to 14 nucleotides (nt) randomly missing at the editing joint. T4 DNA polymerase was then used to repair the Cas9-generated sticky ends, giving substantial improvement in editing accuracy. Plasmid pYH285 and cosmid 10A3, harboring a complete biosynthetic gene cluster for the antibiotics RK-682 and holomycin, respectively, were subjected to the ICE system to delete the rkD and homE genes in frame. Specific insertion of the ampicillin resistance gene (bla) into pYH285 was also successfully performed. These results reveal the ICE system to be a rapid, seamless, and highly efficient way to edit DNA fragments, and a powerful new tool for investigating and engineering biosynthetic gene clusters. IMPORTANCE Recent improvements in cloning strategies for biosynthetic gene clusters promise rapid advances in understanding and exploiting natural products in the environment. For manipulation of such biosynthetic gene clusters to generate valuable bioactive compounds, efficient and specific gene editing of these large DNA fragments is required. In this study, a highly efficient in vitro DNA editing system has been established. When combined with end repair using T4 DNA polymerase, Cas9 precisely and seamlessly catalyzes targeted editing, including in-frame deletion or insertion of the gene(s) of interest. This in vitro CRISPR editing (ICE) system promises a step forward in our ability to engineer biosynthetic pathways.


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 ◽  
Author(s):  
Aman S. Imani ◽  
Aileen R. Lee ◽  
Nisha Vishwanathan ◽  
Floris de Waal ◽  
Michael F. Freeman

Borosins are ribosomally synthesized and post-translationally modified peptides (RiPPs) with α-N-methylations installed on the peptide backbone that impart unique properties like proteolytic stability to these natural products. The borosin RiPP family was initially reported only in fungi until our recent discovery and characterization of a Type IV split borosin system in the metal-respiring bacterium Shewanella oneidensis. Here, we used hidden Markov models and sequence similarity networks to identify over 1,600 putative pathways that show split borosin biosynthetic gene clusters are widespread in bacteria. Noteworthy differences in precursor and α-N-methyltransferase open reading frame sizes, architectures, and core peptide properties allow further subdivision of the borosin family into six additional discrete structural types, of which five have been validated in this study.


2021 ◽  
Author(s):  
Alicia H Russell ◽  
Natalia Miguel Vior ◽  
Edward Steven Hems ◽  
Rodney Lacret ◽  
Andrew William Truman

Ribosomally synthesised and post-translationally modified peptides (RiPPs) are a structurally diverse class of natural product with a wide range of bioactivities. Genome mining for RiPP biosynthetic gene clusters (BGCs) is...


2020 ◽  
Author(s):  
Alicia H. Russell ◽  
Natalia M. Vior ◽  
Edward S. Hems ◽  
Rodney Lacret ◽  
Andrew W. Truman

ABSTRACTRibosomally synthesised and post-translationally modified peptides (RiPPs) are a structurally diverse class of natural product with a range of bioactivities. Genome mining for RiPP biosynthetic gene clusters (BGCs) is often hampered by poor detection of the short precursor peptides that are ultimately modified into the final molecule. Here, we utilise a previously described genome mining tool, RiPPER, to identify novel RiPP precursor peptides near YcaO-domain proteins, enzymes that catalyse various RiPP post-translational modifications including heterocyclisation and thioamidation. Using this dataset, we identified a novel, diverse and highly conserved family of RiPP BGCs spanning over 230 species of Actinobacteria and Firmicutes. A representative BGC from Streptomyces albus J1074 was characterised, leading to the discovery of streptamidine, a novel-amidine containing RiPP. This highlights the breadth of unexplored natural products with structurally rare features, even in model organisms.


2021 ◽  
Author(s):  
Dan Xue ◽  
Ethan A. Older ◽  
Zheng Zhong ◽  
Zhuo Shang ◽  
Nanzhu Chen ◽  
...  

Proteases required for lanthipeptide maturation are not encoded in many of their respective biosynthetic gene clusters. These cryptic proteases hinder the study and application of lanthipeptides as promising drug candidates. Here, we establish a global correlation network bridging the gap between lanthipeptide precursors and cryptic proteases. Applying our analysis to 161,954 bacterial genomes, we establish 6,041 correlations between precursors and cryptic proteases, with 91 prioritized. We use network predictions and co-expression analysis to reveal a previously missing protease for the maturation of class I lanthipeptide paenilan. We further discover widely distributed bacterial M16B metallopeptidases of previously unclear biological function as a new family of lanthipeptide proteases. We show the involvement of a pair of bifunctional M16B proteases in the production of new class III lanthipeptides with high substrate specificity. Together, these results demonstrate the strength of our correlational networking approach to the discovery of cryptic lanthipeptide proteases.


2016 ◽  
Vol 52 (41) ◽  
pp. 6777-6780 ◽  
Author(s):  
B. Bonsch ◽  
V. Belt ◽  
C. Bartel ◽  
N. Duensing ◽  
M. Koziol ◽  
...  

Biosynthetic gene clusters encoding the production of squalestatin S1 have been discovered and exploited to produce new analogs.


2020 ◽  
Vol 99 (8) ◽  
pp. 969-976 ◽  
Author(s):  
S.S. Momeni ◽  
S.M. Beno ◽  
J.L. Baker ◽  
A. Edlund ◽  
T. Ghazal ◽  
...  

Early childhood caries (ECC) is a chronic disease affecting the oral health of children globally. This disease is multifactorial, but a primary factor is cariogenic microorganisms such as Streptococcus mutans. Biosynthetic gene clusters (BGCs) encode small molecules with diverse biological activities that influence the development of many microbial diseases, including caries. The purpose of this study was to identify BGCs in S. mutans from a high-caries risk study population using whole-genome sequencing and assess their association with ECC. Forty representative S. mutans isolates were selected for genome sequencing from a large-scale epidemiological study of oral microbiology and dental caries in children from a localized Alabama population. A total of 252 BGCs were identified using the antiSMASH BGC-mining tool. Three types of BGCs identified herein—butyrolactone-like, ladderane-like, and butyrolactone-ladderane-like hybrid (BL-BGC)—have not been reported in S. mutans. These 3 BGCs were cross-referenced against public transcriptomics data, and were found to be highly expressed in caries subjects. Furthermore, based on a polymerase chain reaction screening for core BL genes, 93% of children with BL-BGC had ECC. The role of BL-BGC was further investigated by examining cariogenic traits and strain fitness in a deletion mutant using in vitro biofilm models. Deletion of the BL-BGC significantly increased biofilm pH as compared to the parent strain, while other virulence and fitness properties remained unchanged. Intriguingly, BL-BGC containing strains produced more acid, a key cariogenic feature, and less biofilm than the model cariogenic strain S. mutans UA159, suggesting the importance of this BL-BGC in S. mutans–mediated cariogenesity. The structure of any BL-BGC derived metabolites, their functions, and mechanistic connection with acid production remain to be elucidated. Nevertheless, this study is the first to report the clinical significance of a BL-BGC in S. mutans. This study also highlights pangenomic diversity, which is likely to affect phenotype and virulence.


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