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Wang M, Zheng J, Sun S, Wu Z, Shao Y, Xiang J, Yin C, Sedjoah RCAA, Xin Z. An Integrated Pipeline and Overexpression of a Novel Efflux Transporter, YoeA, Significantly Increases Plipastatin Production in Bacillus subtilis. Foods 2024; 13:1785. [PMID: 38891014 PMCID: PMC11171584 DOI: 10.3390/foods13111785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 05/25/2024] [Accepted: 05/29/2024] [Indexed: 06/20/2024] Open
Abstract
Plipastatin, an antimicrobial peptide produced by Bacillus subtilis, exhibits remarkable antimicrobial activity against a diverse range of pathogenic bacteria and fungi. However, the practical application of plipastatin has been significantly hampered by its low yield in wild Bacillus species. Here, the native promoters of both the plipastatin operon and the sfp gene in the mono-producing strain M-24 were replaced by the constitutive promoter P43, resulting in plipastatin titers being increased by 27% (607 mg/mL) and 50% (717 mg/mL), respectively. Overexpression of long chain fatty acid coenzyme A ligase (LCFA) increased the yield of plipastatin by 105% (980 mg/mL). A new efflux transporter, YoeA, was identified as a MATE (multidrug and toxic compound extrusion) family member, overexpression of yoeA enhanced plipastatin production to 1233 mg/mL, an increase of 157%, and knockout of yoeA decreased plipastatin production by 70%; in contrast, overexpression or knockout of yoeA in mono-producing surfactin and iturin engineered strains only slightly affected their production, demonstrating that YoeA acts as the major exporter for plipastatin. Co-overexpression of lcfA and yoeA improved plipastatin production to 1890 mg/mL, which was further elevated to 2060 mg/mL after abrB gene deletion. Lastly, the use of optimized culture medium achieved 2514 mg/mL plipastatin production, which was 5.26-fold higher than that of the initial strain. These results suggest that multiple strain engineering is an effective strategy for increasing lipopeptide production, and identification of the novel transport efflux protein YoeA provides new insights into the regulation and industrial application of plipastatin.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Zhihong Xin
- Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China; (M.W.); (J.Z.); (S.S.); (Z.W.); (Y.S.); (J.X.); (C.Y.); (R.C.A.A.S.)
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Gonzalez DI, Ynalvez RA. Comparison of the effects of nitrogen-, sulfur- and combined nitrogen- and sulfur-deprivations on cell growth, lipid bodies and gene expressions in Chlamydomonas reinhardtii cc5373-sta6. BMC Biotechnol 2023; 23:35. [PMID: 37684579 PMCID: PMC10492388 DOI: 10.1186/s12896-023-00808-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
BACKGROUND Biofuel research that aims to optimize growth conditions in microalgae is critically important. Chlamydomonas reinhardtii is a green microalga that offers advantages for biofuel production research. This study compares the effects of nitrogen-, sulfur-, and nitrogen and sulfur- deprivations on the C. reinhardtii starchless mutant cc5373-sta6. Specifically, it compares growth, lipid body accumulation, and expression levels of acetyl-CoA carboxylase (ACC) and phosphoenolpyruvate carboxylase (PEPC). RESULTS Among nutrient-deprived cells, TAP-S cells showed significantly higher total chlorophyll, cell density, and protein content at day 6 (p < 0.05). Confocal analysis showed a significantly higher number of lipid bodies in cells subjected to nutrient deprivation than in the control over the course of six days; N deprivation for six days significantly increased the size of lipid bodies (p < 0.01). In comparison with the control, significantly higher ACC expression was observed after 8 and 24 h of NS deprivation and only after 24 h with N deprivation. On the other hand, ACC and PEPC expression at 8 and 24 h of S deprivation was not significantly different from that in the control. A significantly lower PEPC expression was observed after 8 h of N and NS deprivation (p < 0.01), but a significantly higher PEPC expression was observed after 24 h (p < 0.01). CONCLUSIONS Based on our findings, it would be optimum to cultivate cc5373-sta6 cells in nutrient deprived conditions (-N, -S or -NS) for four days; whereby there is cell growth, and both a high number of lipid bodies and a larger size of lipid bodies produced.
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Affiliation(s)
- David I Gonzalez
- Department of Biological Science, Vanderbilt University, 465 21st Ave S, Nashville, TN, 37240, USA
| | - Ruby A Ynalvez
- Department of Biology and Chemistry, Texas A&M International University, 5201 University Blvd, Laredo, TX, 78041, USA.
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Livieri AL, Colaccini F, Hernández MA, Gago G, Alvarez HM, Gramajo H, Rodriguez E. Genetic analysis of acyl-CoA carboxylases involved in lipid accumulation in Rhodococcus jostii RHA1. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12674-2. [PMID: 37439834 DOI: 10.1007/s00253-023-12674-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 07/14/2023]
Abstract
In actinomycetes, the acyl-CoA carboxylases, including the so-called acetyl-CoA carboxylases (ACCs), are biotin-dependent enzymes that exhibit broad substrate specificity and diverse domain and subunit arrangements. Bioinformatic analyses of the Rhodococcus jostii RHA1 genome found that this microorganism contains a vast arrange of putative acyl-CoA carboxylases domains and subunits. From the thirteen putative carboxyltransferase domains, only the carboxyltransferase subunit RO01202 and the carboxyltransferase domain present in the multidomain protein RO04222 are highly similar to well-known essential ACC subunits from other actinobacteria. Mutant strains in each of these genes showed that none of these enzymes is essential for R. jostii growth in rich or in minimal media with high nitrogen concentration, presumably because of their partial overlapping activities. A mutant strain in the ro04222 gene showed a decrease in triacylglycerol and mycolic acids accumulation in rich and minimal medium, highlighting the relevance of this multidomain ACC in the biosynthesis of these lipids. On the other hand, RO01202, a carboxyltransferase domain of a putative ACC complex, whose biotin carboxylase and biotin carboxyl carrier protein domain were not yet identified, was found to be essential for R. jostii growth only in minimal medium with low nitrogen concentration. The results of this study have identified a new component of the TAG-accumulating machinery in the oleaginous R. jostii RHA1. While non-essential for growth and TAG biosynthesis in RHA1, the activity of RO04222 significantly contributes to lipogenesis during single-cell oil production. Furthermore, this study highlights the high functional diversity of ACCs in actinobacteria, particularly regarding their essentiality under different environmental conditions. KEY POINTS: • R. jostii possess a remarkable heterogeneity in their acyl-carboxylase complexes. • RO04222 is a multidomain acetyl-CoA carboxylase involved in lipid accumulation. • RO01202 is an essential carboxyltransferase only at low nitrogen conditions.
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Affiliation(s)
- Andrea L Livieri
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Facundo Colaccini
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Martin A Hernández
- Instituto de Biociencias de La Patagonia, Facultad de Ciencias Naturales y Ciencias de La Salud, Universidad Nacional de La Patagonia San Juan Bosco y CONICET, Comodoro Rivadavia, Argentina
| | - Gabriela Gago
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Héctor M Alvarez
- Instituto de Biociencias de La Patagonia, Facultad de Ciencias Naturales y Ciencias de La Salud, Universidad Nacional de La Patagonia San Juan Bosco y CONICET, Comodoro Rivadavia, Argentina
| | - Hugo Gramajo
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
| | - Eduardo Rodriguez
- Instituto de Biología Molecular y Celular de Rosario, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
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Gomez-Hinostroza ES, Gurdo N, Alvan Vargas MVG, Nikel PI, Guazzaroni ME, Guaman LP, Castillo Cornejo DJ, Platero R, Barba-Ostria C. Current landscape and future directions of synthetic biology in South America. Front Bioeng Biotechnol 2023; 11:1069628. [PMID: 36845183 PMCID: PMC9950111 DOI: 10.3389/fbioe.2023.1069628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/30/2023] [Indexed: 02/12/2023] Open
Abstract
Synthetic biology (SynBio) is a rapidly advancing multidisciplinary field in which South American countries such as Chile, Argentina, and Brazil have made notable contributions and have established leadership positions in the region. In recent years, efforts have strengthened SynBio in the rest of the countries, and although progress is significant, growth has not matched that of the aforementioned countries. Initiatives such as iGEM and TECNOx have introduced students and researchers from various countries to the foundations of SynBio. Several factors have hindered progress in the field, including scarce funding from both public and private sources for synthetic biology projects, an underdeveloped biotech industry, and a lack of policies to promote bio-innovation. However, open science initiatives such as the DIY movement and OSHW have helped to alleviate some of these challenges. Similarly, the abundance of natural resources and biodiversity make South America an attractive location to invest in and develop SynBio projects.
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Affiliation(s)
- E. Sebastian Gomez-Hinostroza
- Laboratorio de Investigación en Citogenética y Biomoléculas de Anfibios (LICBA), Centro de Investigación para la Salud en América Latina (CISeAL), Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Nicolás Gurdo
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | | | - Pablo I. Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, Denmark
| | | | - Linda P. Guaman
- Centro de Investigación Biomédica (CENBIO), Facultad de Ciencias de la Salud Eugenio Espejo, Universidad UTE, Quito, Ecuador
| | | | - Raúl Platero
- Laboratorio de Microbiología Ambiental, Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Carlos Barba-Ostria
- Escuela de Medicina, Colegio de Ciencias de la Salud Quito, Universidad San Francisco de Quito USFQ, Quito, Ecuador,Instituto de Microbiología, Universidad San Francisco de Quito USFQ, Quito, Ecuador,*Correspondence: Carlos Barba-Ostria,
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Ndembe G, Intini I, Perin E, Marabese M, Caiola E, Mendogni P, Rosso L, Broggini M, Colombo M. LKB1: Can We Target an Hidden Target? Focus on NSCLC. Front Oncol 2022; 12:889826. [PMID: 35646638 PMCID: PMC9131655 DOI: 10.3389/fonc.2022.889826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
LKB1 (liver kinase B1) is a master regulator of several processes such as metabolism, proliferation, cell polarity and immunity. About one third of non-small cell lung cancers (NSCLCs) present LKB1 alterations, which almost invariably lead to protein loss, resulting in the absence of a potential druggable target. In addition, LKB1-null tumors are very aggressive and resistant to chemotherapy, targeted therapies and immune checkpoint inhibitors (ICIs). In this review, we report and comment strategies that exploit peculiar co-vulnerabilities to effectively treat this subgroup of NSCLCs. LKB1 loss leads to an enhanced metabolic avidity, and treatments inducing metabolic stress were successful in inhibiting tumor growth in several preclinical models. Biguanides, by compromising mitochondria and reducing systemic glucose availability, and the glutaminase inhibitor telaglenastat (CB-839), inhibiting glutamate production and reducing carbon intermediates essential for TCA cycle progression, have provided the most interesting results and entered different clinical trials enrolling also LKB1-null NSCLC patients. Nutrient deprivation has been investigated as an alternative therapeutic intervention, giving rise to interesting results exploitable to design specific dietetic regimens able to counteract cancer progression. Other strategies aimed at targeting LKB1-null NSCLCs exploit its pivotal role in modulating cell proliferation and cell invasion. Several inhibitors of LKB1 downstream proteins, such as mTOR, MEK, ERK and SRK/FAK, resulted specifically active on LKB1-mutated preclinical models and, being molecules already in clinical experimentation, could be soon proposed as a specific therapy for these patients. In particular, the rational use in combination of these inhibitors represents a very promising strategy to prevent the activation of collateral pathways and possibly avoid the potential emergence of resistance to these drugs. LKB1-null phenotype has been correlated to ICIs resistance but several studies have already proposed the mechanisms involved and potential interventions. Interestingly, emerging data highlighted that LKB1 alterations represent positive determinants to the new KRAS specific inhibitors response in KRAS co-mutated NSCLCs. In conclusion, the absence of the target did not block the development of treatments able to hit LKB1-mutated NSCLCs acting on several fronts. This will give patients a concrete chance to finally benefit from an effective therapy.
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Affiliation(s)
- Gloriana Ndembe
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Ilenia Intini
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Elisa Perin
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Mirko Marabese
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Elisa Caiola
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Paolo Mendogni
- Thoracic Surgery and Lung Transplantation Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Lorenzo Rosso
- Thoracic Surgery and Lung Transplantation Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Massimo Broggini
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Marika Colombo
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
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Ali I, Khan A, Fa Z, Khan T, Wei DQ, Zheng J. Crystal structure of Acetyl-CoA carboxylase (AccB) from Streptomyces antibioticus and insights into the substrate-binding through in silico mutagenesis and biophysical investigations. Comput Biol Med 2022; 145:105439. [PMID: 35344865 DOI: 10.1016/j.compbiomed.2022.105439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 03/14/2022] [Accepted: 03/20/2022] [Indexed: 11/18/2022]
Abstract
Acetyl-CoA carboxylase (ACC) is crucial for polyketides biosynthesis and acts as an essential metabolic checkpoint. It is also an attractive drug target against obesity, cancer, microbial infections, and diabetes. However, the lack of knowledge, particularly sequence-structure function relationship to narrate ligand-enzyme binding, has hindered the progress of ACC-specific therapeutics and unnatural "natural" polyketides. Structural characterization of such enzymes will boost the opportunity to understand the substrate binding, designing new inhibitors and information regarding the molecular rules which control the substrate specificity of ACCs. To understand the substrate specificity, we determined the crystal structure of AccB (Carboxyl-transferase, CT) from Streptomyces antibioticus with a resolution of 2.3 Å and molecular modeling approaches were employed to unveil the molecular mechanism of acetyl-CoA recognition and processing. The CT domain of S. antibioticus shares a similar structural organization with the previous structures and the two steps reaction was confirmed by enzymatic assay. Furthermore, to reveal the key hotspots required for the substrate recognition and processing, in silico mutagenesis validated only three key residues (V223, Q346, and Q514) that help in the fixation of the substrate. Moreover, we also presented atomic level knowledge on the mechanism of the substrate binding, which unveiled the terminal loop (500-514) function as an opening and closing switch and pushes the substrate inside the cavity for stable binding. A significant decline in the hydrogen bonding half-life was observed upon the alanine substitution. Consequently, the presented structural data highlighted the potential key interacting residues for substrate recognition and will also help to re-design ACCs active site for proficient substrate specificity to produce diverse polyketides.
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Affiliation(s)
- Imtiaz Ali
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Abbas Khan
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Zhang Fa
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Taimoor Khan
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Dong-Qing Wei
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China; State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200030, PR China; Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nashan District, Shenzhen, Guangdong, 518055, PR China
| | - Jianting Zheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China; Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai, PR China.
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Sitarz K, Czamara K, Bialecka J, Klimek M, Szostek S, Kaczor A. Dual Switch in Lipid Metabolism in Cervical Epithelial Cells during Dysplasia Development Observed Using Raman Microscopy and Molecular Methods. Cancers (Basel) 2021; 13:1997. [PMID: 33919178 PMCID: PMC8122332 DOI: 10.3390/cancers13091997] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 01/31/2023] Open
Abstract
Cellular lipid metabolism is significantly transformed during oncogenesis. To assess how dysplasia development influences lipid cellular metabolisms and what is the molecular background behind it, cervical epithelial cells of 63 patients assigned to seven groups (based on the cytological examination and HPVhr test results) were studied using a multimethodological approach including Raman microscopy and molecular methods. The consistent picture obtained studying the lipid content, cell inflammation, SREBF1 gene methylation (hence SREBP1 inhibition) and level of mitochondrial DNA copies (indirectly the number of mitochondria) showed that changes in lipid metabolism were multidirectional. Cells from patients classified as mildly dysplastic (LSIL) exhibited a unique behavior (the highest level of inflammation and SREBF1 methylation, the lowest lipid content and mitochondrial DNA). On the contrary, cells from severe dysplastic (HSIL) and cancer (SCC) groups showed the opposite characteristics including the lowest SREBF1 gene methylation as well as the highest level of mitochondrial DNA and lipid cellular concentration (for HSIL/HPVhr+ and SCC groups). Following dysplastic progression, the lipid content decreases significantly (compared to the control) for mildly abnormal cells, but then increases for HSIL/HPVhr+ and SCC groups. This intriguing dual switch in lipid metabolism (reflected also in other studied parameters) on the way from normal to squamous carcinoma cells is of potential diagnostic interest.
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Affiliation(s)
- Katarzyna Sitarz
- Chair of Microbiology, Department of Molecular Medical Microbiology, Faculty of Medicine, Jagiellonian University Medical College, 18 Czysta Street, 31-121 Krakow, Poland;
- Faculty of Chemistry, Jagiellonian University, 2 Gronostajowa Street, 30-387 Krakow, Poland
| | - Krzysztof Czamara
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, 14 Bobrzynskiego Street, 30-348 Krakow, Poland;
| | - Joanna Bialecka
- Centre of Microbiological Research and Autovaccines, 17 Slawkowska Street, 31-016 Krakow, Poland;
| | - Malgorzata Klimek
- Clinic of Radiotherapy, Maria Sklodowska-Curie Institute—Oncology Center, 11 Garncarska Street, 31-115 Krakow, Poland;
| | - Slawa Szostek
- Chair of Microbiology, Department of Molecular Medical Microbiology, Faculty of Medicine, Jagiellonian University Medical College, 18 Czysta Street, 31-121 Krakow, Poland;
| | - Agnieszka Kaczor
- Faculty of Chemistry, Jagiellonian University, 2 Gronostajowa Street, 30-387 Krakow, Poland
- Jagiellonian Centre for Experimental Therapeutics (JCET), Jagiellonian University, 14 Bobrzynskiego Street, 30-348 Krakow, Poland;
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AccR, a TetR Family Transcriptional Repressor, Coordinates Short-Chain Acyl Coenzyme A Homeostasis in Streptomyces avermitilis. Appl Environ Microbiol 2020; 86:AEM.00508-20. [PMID: 32303550 DOI: 10.1128/aem.00508-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/15/2020] [Indexed: 02/07/2023] Open
Abstract
Malonyl coenzyme A (malonyl-CoA) and methylmalonyl-CoA are the most common extender units for the biosynthesis of fatty acids and polyketides in Streptomyces, an industrially important producer of polyketides. Carboxylation of acetyl- and propionyl-CoAs is an essential source of malonyl- and methylmalonyl-CoAs; therefore, acyl-CoA carboxylases (ACCases) play key roles in primary and secondary metabolism. The regulation of the expression of ACCases in Streptomyces spp. has not been investigated previously. We characterized a TetR family transcriptional repressor, AccR, that mediates intracellular acetyl-, propionyl-, methylcrotonyl-, malonyl-, and methylmalonyl-CoA levels by controlling the transcription of genes that encode the main ACCase and enzymes associated with branched-chain amino acid metabolism in S. avermitilis AccR bound to a 16-nucleotide palindromic binding motif (GTTAA-N6-TTAAC) in promoter regions and repressed the transcription of the accD1A1-hmgL-fadE4 operon, echA8, echA9, and fadE2, which are involved in the production and assimilation of acetyl- and propionyl-CoAs. Methylcrotonyl-, propionyl-, and acetyl-CoAs acted as effectors to release AccR from its target DNA, resulting in enhanced transcription of target genes by derepression. The affinity of methylcrotonyl- and propionyl-CoAs to AccR was stronger than that of acetyl-CoA. Deletion of accR resulted in increased concentrations of short-chain acyl-CoAs (acetyl-, propionyl-, malonyl-, and methylmalonyl-CoAs), leading to enhanced avermectin production. Avermectin production was increased by 14.5% in an accR deletion mutant of the industrial high-yield strain S. avermitilis A8. Our findings clarify the regulatory mechanisms that maintain the homeostasis of short-chain acyl-CoAs in Streptomyces IMPORTANCE Acyl-CoA carboxylases play key roles in primary and secondary metabolism. However, the regulation of ACCase genes transcription in Streptomyces spp. remains unclear. Here, we demonstrated that AccR responded to intracellular acetyl-, propionyl-, and methylcrotonyl-CoA availability and mediated transcription of the genes related to production and assimilation of these compounds in S. avermitilis When intracellular concentrations of these compounds are low, AccR binds to target genes and represses their transcription, resulting in low production of malonyl- and methylmalonyl-CoAs. When intracellular acetyl-, propionyl-, and methylcrotonyl-CoA concentrations are high, these compounds bind to AccR to dissociate AccR from target DNA, promoting the conversion of these compounds to malonyl- and methylmalonyl-CoAs. This investigation revealed how AccR coordinates short-chain acyl-CoA homeostasis in Streptomyces.
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