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Schulz S, Schall C, Stehle T, Breitmeyer C, Krysenko S, Mitulski A, Wohlleben W. Optimization of the precursor supply for an enhanced FK506 production in Streptomyces tsukubaensis. Front Bioeng Biotechnol 2022; 10:1067467. [DOI: 10.3389/fbioe.2022.1067467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022] Open
Abstract
Tacrolimus (FK506) is a macrolide widely used as immunosuppressant to prevent transplant rejection. Synthetic production of FK506 is not efficient and costly, whereas the biosynthesis of FK506 is complex and the level produced by the wild type strain, Streptomyces tsukubaensis, is very low. We therefore engineered FK506 biosynthesis and the supply of the precursor L-lysine to generate strains with improved FK506 yield. To increase FK506 production, first the intracellular supply of the essential precursor lysine was improved in the native host S. tsukubaensis NRRL 18488 by engineering the lysine biosynthetic pathway. Therefore, a feedback deregulated aspartate kinase AskSt* of S. tsukubaensis was generated by site directed mutagenesis. Whereas overexpression of AskSt* resulted only in a 17% increase in FK506 yield, heterologous overexpression of a feedback deregulated AskCg* from Corynebacterium glutamicum was proven to be more efficient. Combined overexpression of AskCg* and DapASt, showed a strong enhancement of the intracellular lysine pool following increase in the yield by approximately 73% compared to the wild type. Lysine is coverted into the FK506 building block pipecolate by the lysine cyclodeaminase FkbL. Construction of a ∆fkbL mutant led to a complete abolishment of the FK506 production, confirming the indispensability of this enzyme for FK506 production. Chemical complementation of the ∆fkbL mutant by feeding pipecolic acid and genetic complementation with fkbL as well as with other lysine cyclodeaminase genes (pipAf, pipASt, originating from Actinoplanes friuliensis and Streptomyces pristinaespiralis, respectively) completely restored FK506 production. Subsequently, FK506 production was enchanced by heterologous overexpression of PipAf and PipASp in S. tsukubaensis. This resulted in a yield increase by 65% compared to the WT in the presence of PipAf from A. friuliensis. For further rational yield improvement, the crystal structure of PipAf from A. friuliensis was determined at 1.3 Å resolution with the cofactor NADH bound and at 1.4 Å with its substrate lysine. Based on the structure the Ile91 residue was replaced by Val91 in PipAf, which resulted in an overall increase of FK506 production by approx. 100% compared to the WT.
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A genome-scale dynamic flux balance analysis model of Streptomyces tsukubaensis NRRL18488 to predict the targets for increasing FK506 production. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.03.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Xu J, Han M, Ren X, Zhang W. Modification of aspartokinase III and dihydrodipicolinate synthetase increases the production of l-lysine in Escherichia coli. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2016.06.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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A specialized aspartokinase enhances the biosynthesis of the osmoprotectants ectoine and hydroxyectoine in Pseudomonas stutzeri A1501. J Bacteriol 2011; 193:4456-68. [PMID: 21725014 DOI: 10.1128/jb.00345-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The compatible solutes ectoine and hydroxyectoine are widely produced by bacteria as protectants against osmotic and temperature stress. l-Aspartate-beta-semialdehyde is used as the precursor molecule for ectoine/hydroxyectoine biosynthesis that is catalyzed by the EctABCD enzymes. l-Aspartate-beta-semialdehyde is a central intermediate in different biosynthetic pathways and is produced from l-aspartate by aspartokinase (Ask) and aspartate-semialdehyde-dehydrogenase (Asd). Ask activity is typically stringently regulated by allosteric control to avoid gratuitous synthesis of aspartylphosphate. Many organisms have evolved multiple forms of aspartokinase, and feedback regulation of these specialized Ask enzymes is often adapted to the cognate biochemical pathways. The ectoine/hydroxyectoine biosynthetic genes (ectABCD) are followed in a considerable number of microorganisms by an askgene (ask_ect), suggesting that Ask_Ect is a specialized enzyme for this osmoadaptive biosynthetic pathway. However, none of these Ask_Ect enzymes have been functionally characterized. Pseudomonas stutzeri A1501 synthesizes both ectoine and hydroxyectoine in response to increased salinity, and it possesses two Ask enzymes: Ask_Lys and Ask_Ect. We purified both Ask enzymes and found significant differences with regard to their allosteric control: Ask_LysC was inhibited by threonine and in a concerted fashion by threonine and lysine, whereas Ask_Ect showed inhibition only by threonine. The ectABCD_askgenes from P. stutzeri A1501 were cloned and functionally expressed in Escherichia coli, and this led to osmostress protection. An E. colistrain carrying the plasmid-based ectABCD_askgene cluster produced significantly more ectoine/hydroxyectoine than a strain expressing the ectABCDgene cluster alone. This finding suggests a specialized role for Ask_Ect in ectoine/hydroxyectoine biosynthesis.
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Özcengiz G, Okay S, Ünsaldı E, Taşkın B, Liras P, Piret J. Homologous expression of aspartokinase (ask) gene in Streptomyces clavuligerus and its hom-deleted mutant: effects on cephamycin C production. Bioeng Bugs 2010; 1:191-7. [PMID: 21326925 DOI: 10.4161/bbug.1.3.11244] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 01/07/2010] [Accepted: 01/11/2010] [Indexed: 11/19/2022] Open
Abstract
In this study, the effect of homologous multiple copies of the ask gene, which encodes aspartokinase catalyzing the first step of the aspartate pathway, on cephamycin C biosynthesis in S. clavuligerus NRRL 3585 and its hom mutant was investigated. The intracellular pool levels of aspartate pathway amino acids accorded well with the Ask activity levels in TB3585 and AK39. When compared with the control strain carrying vector alone without any gene insert, amplification of the ask gene in the wild strain resulted in a maximum of 3.1- and 3.3-fold increase in specific, 1.7- and 1.9-fold increase in volumetric cephamycin C production when grown in trypticase soy broth (TSB) and a modified chemically defined medium (mCDM), respectively. However, expression of multicopy ask gene in a hom-deleted background significantly decreased cephamycin C yields when the cells were grown in either TSB or mCDM, most probably due to physiological disturbance resulting from enzyme overexpression and high copy number plasmid burden in an auxotrophic host, respectively.
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Affiliation(s)
- Gülay Özcengiz
- Department of Biology, Middle East Technical University, Ankara, Turkey.
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Hamano Y, Nicchu I, Shimizu T, Onji Y, Hiraki J, Takagi H. epsilon-Poly-L: -lysine producer, Streptomyces albulus, has feedback-inhibition resistant aspartokinase. Appl Microbiol Biotechnol 2007; 76:873-82. [PMID: 17611754 DOI: 10.1007/s00253-007-1052-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 05/11/2007] [Accepted: 05/22/2007] [Indexed: 10/23/2022]
Abstract
Streptomyces albulus NBRC14147 produces epsilon-poly-L: -lysine (epsilon-PL), which is an amino acid homopolymer antibiotic. Despite the commercial importance of epsilon-PL, limited information is available regarding its biosynthesis; the L: -lysine molecule is directly utilized for epsilon-PL biosynthesis. In most bacteria, L: -lysine is biosynthesized by an aspartate pathway. Aspartokinase (Ask), which is the first enzyme in this pathway, is subject to complex regulation such as through feedback inhibition by the end-product amino acids such as L: -lysine and/or L: -threonine. S. albulus NBRC14147 can produce a large amount of epsilon-PL (1-3 g/l). We therefore suspected that Ask(s) of S. albulus could be resistant to feedback inhibition to provide sufficient L: -lysine for epsilon-PL biosynthesis. To address this hypothesis, in this study, we cloned the ask gene from S. albulus and investigated the feedback inhibition of its gene product. As predicted, we revealed the feedback resistance of the Ask; more than 20% relative activity of Ask was detected in the assay mixture even with extremely high concentrations of L: -lysine and L: -threonine (100 mM each). We further constructed a mutated ask gene for which the gene product Ask (M68V) is almost fully resistant to feedback inhibition. The homologous expression of Ask (M68V) further demonstrated the increase in epsilon-PL productivity.
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Affiliation(s)
- Y Hamano
- Department of Bioscience, Fukui Prefectural University, 4-1-1 Matsuoka-Kenjojima, Eiheiji-cho, Fukui, 910-1195, Japan.
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Velasco I, Arévalo-Rodríguez M, Marina P, Calderón IL. A new mutation in the yeast aspartate kinase induces threonine accumulation in a temperature-regulated way. Yeast 2005; 22:99-110. [PMID: 15645479 DOI: 10.1002/yea.1197] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In Saccharomyces cerevisiae, aspartate kinase (the HOM3 product) regulates the metabolic flux through the threonine biosynthetic pathway through feedback inhibition by the end product. In order to obtain a strain able to produce threonine in a controlled way, we have isolated a mutant allele (HOM3-ts31d) that gives rise to a deregulated aspartate kinase. This allele has been isolated as an extragenic suppressor of ilv1, which confers an Ilv+ phenotype at 37 degrees C but not at 22 degrees C. We have stated that at high temperature the mutant aspartate kinase is slightly more deregulated and shows a higher specific activity, inducing threonine accumulation. The HOM3-ts31d allele carries a mutation that leads to a Ser399 --> Phe substitution in the postulated regulatory region of the enzyme. We have detected other changes in the nucleotide sequence but they are also present in the parental strain, reflecting the genetic differences between different wild-type strains. A sequence comparison among all the reported mutant aspartate kinases suggests that not all residues involved in regulation of the activity are clustered in the so-called regulatory domain, as is the case of that mutated in AK-R7, another deregulated aspartate kinase obtained with the same strategy of ilv1 suppression.
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Affiliation(s)
- I Velasco
- Departamento de Genética, Universidad de Sevilla, Sevilla, Spain
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Tunca S, Yilmaz EI, Piret J, Liras P, Ozcengiz G. Cloning, characterization and heterologous expression of the aspartokinase and aspartate semialdehyde dehydrogenase genes of cephamycin C-producer Streptomyces clavuligerus. Res Microbiol 2004; 155:525-34. [PMID: 15313252 DOI: 10.1016/j.resmic.2004.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 03/24/2004] [Indexed: 10/26/2022]
Abstract
Carbon flow through the lysine branch of the aspartate biosynthetic pathway is a rate-limiting step in the formation of cephamycin C, a broad spectrum beta-lactam antibiotic produced by Streptomyces clavuligerus. In this study, genes which encode the enzymes catalyzing the first two steps of the aspartate pathway, ask (aspartokinase) and asd (aspartate semialdehyde dehydrogenase), in S. clavuligerus NRRL 3585 were cloned and sequenced. Nucleotide sequencing and codon preference analysis revealed three complete open reading frames (ORFs). ORF2 starts within ORF1 and terminates by utilizing the same stop codon as ORF1, an arrangement typical of many ask genes. ORF3 is located 2 nucleotides downstream of ORF1,2. Database comparisons with these proteins identified ORF1 as the large (alpha) subunit of aspartokinase, ORF2 as the small (beta) subunit of aspartokinase and ORF3 as the aspartate semialdehyde dehydrogenase. The cloned genes were functionally expressed in auxotrophic Escherichia coli strains, CGSC5074 (ask(-)) and E. coli CGSC5080 (asd(-)), the two enzymes were partially purified from E. coli cell extracts and their kinetic parameters were determined. The effects of end product amino acids and diaminopimelic acid on the activity of Ask and Asd enzymes were also described.
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Affiliation(s)
- Sedef Tunca
- Department of Biology, Middle East Technical University, Ankara, Turkey
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Fernández M, Cuadrado Y, Recio E, Aparicio JF, Martı N JF. Characterization of the hom-thrC-thrB cluster in aminoethoxyvinylglycine-producing Streptomyces sp. NRRL 5331. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1413-1420. [PMID: 11988515 DOI: 10.1099/00221287-148-5-1413] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Three genes from the aminoethoxyvinylglycine (AVG)-producing Streptomyces sp. NRRL 5331 involved in threonine biosynthesis, hom, thrB and thrC, encoding homoserine dehydrogenase (HDH), homoserine kinase (HK) and threonine synthase (TS), respectively, have been cloned and sequenced. The hom and thrC genes appear to be organized in a bicistronic operon as deduced by disruption experiments. The thrB gene, however, is transcribed as a monocistronic transcript. The encoded proteins are quite similar to the HDH, HK and TS proteins from other bacterial species. The overall organization of these three genes, in the order hom-thrC-thrB, differs from that in other bacteria and is similar to that reported in the Streptomyces coelicolor genome sequence. This is the first time in which the gene cluster for the three last steps of threonine biosynthesis has been characterized from a streptomycete. Disruption of thrC indicated that threonine is not a direct precursor for AVG biosynthesis in Streptomyces sp. NRRL 5331 and suggested that the branching point of the aspartic acid-derived biosynthetic route of this metabolite should lie earlier on the threonine biosynthetic route.
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Affiliation(s)
- Mónica Fernández
- Institute of Biotechnology INBIOTEC, Parque Cientı́fico de León, Avda. del Real, no 1, 24006 León, Spain1
| | - Yolanda Cuadrado
- Institute of Biotechnology INBIOTEC, Parque Cientı́fico de León, Avda. del Real, no 1, 24006 León, Spain1
| | - Eliseo Recio
- Institute of Biotechnology INBIOTEC, Parque Cientı́fico de León, Avda. del Real, no 1, 24006 León, Spain1
| | - Jesús F Aparicio
- Area of Microbiology, Faculty of Biology, University of León, 24071 León, Spain2
- Institute of Biotechnology INBIOTEC, Parque Cientı́fico de León, Avda. del Real, no 1, 24006 León, Spain1
| | - Juan F Martı N
- Area of Microbiology, Faculty of Biology, University of León, 24071 León, Spain2
- Institute of Biotechnology INBIOTEC, Parque Cientı́fico de León, Avda. del Real, no 1, 24006 León, Spain1
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