scholarly journals Characterization of Methyltransferase from Apramycin Biosynthetic Gene Cluster and Improvement Production of Apramycin in Engineered Streptoalloteichus Tenebrarius

2021 ◽  
Author(s):  
Junyang Sun ◽  
Hongjing Gao ◽  
Danyang Yan ◽  
Yu Liu ◽  
Xianpu Ni ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gene Disruption ◽  
Pasteurella Multocida ◽  
Aminoglycoside Antibiotic ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Methyltransferase Gene ◽  
Production Strain

Abstract BackgroundApramycin is a structurally unique aminoglycoside, used in veterinary medicine or the treatment of Salmonella, Escherichia coli and Pasteurella multocida infections in farm. Although discovered and used many years ago, many biosynthetic steps of apramycin are still obscure. ResultsIn this study, we identified a HemK family methyltransferase, aprI, involved in apramycin biosynthesis. The function of aprI was studied by using gene disruption and biochemical experiments, and a new aminoglycoside antibiotic demethyl-apramycin was purified from aprI disruption strain. Experiments proved that AprI converted demethyl-aprosamine to aprosamine in vitro. Based on this, the apramycin production strain was improved by overexpression the AprI to decrease the impurity production. ConclusionsWe have identified aprI is a 7’-N-methyltransferase gene in apramycin biosynthesis and confirmed the substrate of methyltransferase. Engineering of aprI resulted in a strain producing a new aminoglycoside demethyl-apramycin and apramycin mono-producing strain with less impurity production. Finally, the yield of demethyl-apramycin in apramycin mono-producing strain decreased from 196±36 mg/L to 51±9 mg/L, and the yield of apramycin increased from 2227±320 mg/L to 2331±210 mg/L.

scholarly journals Analysis of the Mycosamine Biosynthesis and Attachment Genes in the Nystatin Biosynthetic Gene Cluster of Streptomyces noursei ATCC 11455

2007 ◽  
Vol 73 (22) ◽  
pp. 7400-7407 ◽  
Author(s):  
Aina Nedal ◽  
Håvard Sletta ◽  
Trygve Brautaset ◽  
Sven E. F. Borgos ◽  
Olga N. Sekurova ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biological Activity ◽  
Gene Cluster ◽  
Macrolide Antibiotic ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Polyene Macrolide Antibiotic ◽  
Streptomyces Noursei ◽  
Dehydratase Activity

ABSTRACT The polyene macrolide antibiotic nystatin produced by Streptomyces noursei contains a deoxyaminosugar mycosamine moiety attached to the C-19 carbon of the macrolactone ring through the β-glycosidic bond. The nystatin biosynthetic gene cluster contains three genes, nysDI, nysDII, and nysDIII, encoding enzymes with presumed roles in mycosamine biosynthesis and attachment as glycosyltransferase, aminotransferase, and GDP-mannose dehydratase, respectively. In the present study, the functions of these three genes were analyzed. The recombinant NysDIII protein was expressed in Escherichia coli and purified, and its in vitro GDP-mannose dehydratase activity was demonstrated. The nysDI and nysDII genes were inactivated individually in S. noursei, and analyses of the resulting mutants showed that both genes produced nystatinolide and 10-deoxynystatinolide as major products. Expression of the nysDI and nysDII genes in trans in the respective mutants partially restored nystatin biosynthesis in both cases, supporting the predicted roles of these two genes in mycosamine biosynthesis and attachment. Both antifungal and hemolytic activities of the purified nystatinolides were shown to be strongly reduced compared to those of nystatin, confirming the importance of the mycosamine moiety for the biological activity of nystatin.

scholarly journals Characterization of the coformycin biosynthetic gene cluster in Streptomyces kaniharaensis

2020 ◽  
Vol 117 (19) ◽  
pp. 10265-10270
Author(s):  
Daan Ren ◽  
Mark W. Ruszczycky ◽  
Yeonjin Ko ◽  
Shao-An Wang ◽  
Yasushi Ogasawara ◽  
...  
Keyword(s):  
Adenosine Deaminase ◽  
Gene Cluster ◽  
Branch Point ◽  
Biosynthetic Pathway ◽  
Biosynthetic Gene Cluster ◽  
Biosynthetic Gene ◽  
Histidine Biosynthesis ◽  
Nucleoside Inhibitors

Coformycin and pentostatin are structurally related N-nucleoside inhibitors of adenosine deaminase characterized by an unusual 1,3-diazepine nucleobase. Herein, the cof gene cluster responsible for coformycin biosynthesis is identified. Reconstitution of the coformycin biosynthetic pathway in vitro demonstrates that it overlaps significantly with the early stages of l-histidine biosynthesis. Committed entry into the coformycin pathway takes place via conversion of a shared branch point intermediate to 8-ketocoformycin-5′-monophosphate catalyzed by CofB, which is a homolog of succinylaminoimidazolecarboxamide ribotide (SAICAR) synthetase. This reaction appears to proceed via a Dieckmann cyclization and a retro-aldol elimination, releasing ammonia and D-erythronate-4-phosphate as coproducts. Completion of coformycin biosynthesis involves reduction and dephosphorylation of the CofB product, with the former reaction being catalyzed by the NADPH-dependent dehydrogenase CofA. CofB also shows activation by adenosine triphosphate (ATP) despite the reaction requiring neither a phosphorylated nor an adenylated intermediate. This may serve to help regulate metabolic partitioning between the l-histidine and coformycin pathways.

scholarly journals The role of the TetR-family transcriptional regulator Aur1R in negative regulation of the auricin gene cluster in Streptomyces aureofaciens CCM 3239

Microbiology ◽  
2010 ◽  
Vol 156 (8) ◽  
pp. 2374-2383 ◽  
Author(s):  
Renata Novakova ◽  
Peter Kutas ◽  
Lubomira Feckova ◽  
Jan Kormanec
Keyword(s):  
Gene Cluster ◽  
Biosynthetic Gene Cluster ◽  
Transcriptional Repressors ◽  
Biosynthetic Gene ◽  
Response Regulators ◽  
Streptomyces Aureofaciens ◽  
Two Component Signal Transduction

Two regulatory genes, aur1P and aur1R, have been previously identified upstream of the aur1 polyketide gene cluster involved in biosynthesis of the angucycline-like antibiotic auricin in Streptomyces aureofaciens CCM 3239. The aur1P gene encodes a protein similar to the response regulators of bacterial two-component signal transduction systems and has been shown to specifically activate expression of the auricin biosynthetic genes. The aur1R gene encodes a protein homologous to transcriptional repressors of the TetR family. Here we describe the characterization of the aur1R gene. Expression of the gene is directed by a single promoter, aur1Rp, which is induced just before stationary phase. Disruption of aur1R in S. aureofaciens CCM 3239 had no effect on growth and differentiation. However, the disrupted strain produced more auricin than its parental wild-type S. aureofaciens CCM 3239 strain. Transcription from the aur1Ap and aur1Pp promoters, directing expression of the first biosynthetic gene in the auricin gene cluster and the pathway-specific transcriptional activator, respectively, was increased in the S. aureofaciens CCM 3239 aur1R mutant strain. However, Aur1R was shown to bind specifically only to the aur1Pp promoter in vitro. This binding was abolished by the addition of auricin and/or its intermediates. The results indicate that the Aur1R regulator specifically represses expression of the aur1P gene, which encodes a pathway-specific activator of the auricin biosynthetic gene cluster in S. aureofaciens CCM 3239, and that this repression is relieved by auricin or its intermediates.

scholarly journals Characterization of the fomA andfomB Gene Products from Streptomyces wedmorensis, Which Confer Fosfomycin Resistance on Escherichia coli

2000 ◽  
Vol 44 (3) ◽  
pp. 647-650 ◽  
Author(s):  
Seiji Kobayashi ◽  
Tomohisa Kuzuyama ◽  
Haruo Seto
Keyword(s):  
Escherichia Coli ◽  
Resistance Mechanism ◽  
Biosynthetic Gene Cluster ◽  
Magnesium Ion ◽  
Gene Products ◽  
Biosynthetic Gene ◽  
E Coli ◽  
Fosfomycin Resistance ◽  
High Level

ABSTRACT Together, the fomA and fomB genes in the fosfomycin biosynthetic gene cluster of Streptomyces wedmorensis confer high-level fosfomycin resistance onEscherichia coli. To elucidate their functions, thefomA and fomB genes were overexpressed inE. coli and the gene products were characterized. The recombinant FomA protein converted fosfomycin to fosfomycin monophosphate, which was inactive on E. coli, in the presence of a magnesium ion and ATP. On the other hand, the recombinant FomB protein did not inactivate fosfomycin. However, a reaction mixture containing FomA and FomB proteins converted fosfomycin to fosfomycin monophosphate and fosfomycin diphosphate in the presence of ATP and a magnesium ion, indicating that FomA and FomB catalyzed phosphorylations of fosfomycin and fosfomycin monophosphate, respectively. These results suggest that the self-resistance mechanism of the fosfomycin-producing organism S. wedmorensis is mono- and diphosphorylation of the phosphonate function of fosfomycin catalyzed by FomA and FomB.

scholarly journals Engineering of Streptoalloteichus tenebrarius 2444 for Sustainable Production of Tobramycin

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4343
Author(s):  
Lena Mitousis ◽  
Hannes Maier ◽  
Luka Martinovic ◽  
Andreas Kulik ◽  
Sigrid Stockert ◽  
...  
Keyword(s):  
Aminoglycoside Antibiotic ◽  
Biosynthetic Gene Cluster ◽  
Genetically Engineered ◽  
Sustainable Production ◽  
Biosynthetic Gene ◽  
Strain Development ◽  
Antibiotic Agent ◽  
Phenotypic Stability ◽  
High Concentrations ◽  
Hydrolysis Of

Tobramycin is a broad-spectrum aminoglycoside antibiotic agent. The compound is obtained from the base-catalyzed hydrolysis of carbamoyltobramycin (CTB), which is naturally produced by the actinomycete Streptoalloteichus tenebrarius. However, the strain uses the same precursors to synthesize several structurally related aminoglycosides. Consequently, the production yields of tobramycin are low, and the compound’s purification is very challenging, costly, and time-consuming. In this study, the production of the main undesired product, apramycin, in the industrial isolate Streptoalloteichus tenebrarius 2444 was decreased by applying the fermentation media M10 and M11, which contained high concentrations of starch and dextrin. Furthermore, the strain was genetically engineered by the inactivation of the aprK gene (∆aprK), resulting in the abolishment of apramycin biosynthesis. In the next step of strain development, an additional copy of the tobramycin biosynthetic gene cluster (BGC) was introduced into the ∆aprK mutant. Fermentation by the engineered strain (∆aprK_1-17L) in M11 medium resulted in a 3- to 4-fold higher production than fermentation by the precursor strain (∆aprK). The phenotypic stability of the mutant without selection pressure was validated. The use of the engineered S. tenebrarius 2444 facilitates a step-saving, efficient, and, thus, more sustainable production of the valuable compound tobramycin on an industrial scale.

scholarly journals Characterization of a Dye-Decolorizing Peroxidase from Irpex lacteus Expressed in Escherichia coli: An Enzyme with Wide Substrate Specificity Able to Transform Lignosulfonates

2021 ◽  
Vol 7 (5) ◽  
pp. 325
Author(s):  
Laura Isabel de de Eugenio ◽  
Rosa Peces-Pérez ◽  
Dolores Linde ◽  
Alicia Prieto ◽  
Jorge Barriuso ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Inclusion Bodies ◽  
Veratryl Alcohol ◽  
Dye Decolorization ◽  
Irpex Lacteus ◽  
Type D ◽  
Lignin Peroxidases

A dye-decolorizing peroxidase (DyP) from Irpex lacteus was cloned and heterologously expressed as inclusion bodies in Escherichia coli. The protein was purified in one chromatographic step after its in vitro activation. It was active on ABTS, 2,6-dimethoxyphenol (DMP), and anthraquinoid and azo dyes as reported for other fungal DyPs, but it was also able to oxidize Mn2+ (as manganese peroxidases and versatile peroxidases) and veratryl alcohol (VA) (as lignin peroxidases and versatile peroxidases). This corroborated that I. lacteus DyPs are the only enzymes able to oxidize high redox potential dyes, VA and Mn+2. Phylogenetic analysis grouped this enzyme with other type D-DyPs from basidiomycetes. In addition to its interest for dye decolorization, the results of the transformation of softwood and hardwood lignosulfonates suggest a putative biological role of this enzyme in the degradation of phenolic lignin.

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