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Interconnected Set of Enzymes Provide Lysine Biosynthetic Intermediates and Ornithine Derivatives as Key Precursors for the Biosynthesis of Bioactive Secondary Metabolites. Antibiotics (Basel) 2023; 12:antibiotics12010159. [PMID: 36671360 PMCID: PMC9854754 DOI: 10.3390/antibiotics12010159] [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: 12/15/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023] Open
Abstract
Bacteria, filamentous fungi, and plants synthesize thousands of secondary metabolites with important biological and pharmacological activities. The biosynthesis of these metabolites is performed by networks of complex enzymes such as non-ribosomal peptide synthetases, polyketide synthases, and terpenoid biosynthetic enzymes. The efficient production of these metabolites is dependent upon the supply of precursors that arise from primary metabolism. In the last decades, an impressive array of biosynthetic enzymes that provide specific precursors and intermediates leading to secondary metabolites biosynthesis has been reported. Suitable knowledge of the elaborated pathways that synthesize these precursors or intermediates is essential for advancing chemical biology and the production of natural or semisynthetic biological products. Two of the more prolific routes that provide key precursors in the biosynthesis of antitumor, immunosuppressant, antifungal, or antibacterial compounds are the lysine and ornithine pathways, which are involved in the biosynthesis of β-lactams and other non-ribosomal peptides, and bacterial and fungal siderophores. Detailed analysis of the molecular genetics and biochemistry of the enzyme system shows that they are formed by closely related components. Particularly the focus of this study is on molecular genetics and the enzymatic steps that lead to the formation of intermediates of the lysine pathway, such as α-aminoadipic acid, saccharopine, pipecolic acid, and related compounds, and of ornithine-derived molecules, such as N5-Acetyl-N5-Hydroxyornithine and N5-anhydromevalonyl-N5-hydroxyornithine, which are precursors of siderophores. We provide evidence that shows interesting functional relationships between the genes encoding the enzymes that synthesize these products. This information will contribute to a better understanding of the possibilities of advancing the industrial applications of synthetic biology.
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Martin JF, Alvarez-Alvarez R, Liras P. Penicillin-Binding Proteins, β-Lactamases, and β-Lactamase Inhibitors in β-Lactam-Producing Actinobacteria: Self-Resistance Mechanisms. Int J Mol Sci 2022; 23:5662. [PMID: 35628478 PMCID: PMC9146315 DOI: 10.3390/ijms23105662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/14/2022] [Accepted: 05/16/2022] [Indexed: 01/27/2023] Open
Abstract
The human society faces a serious problem due to the widespread resistance to antibiotics in clinical practice. Most antibiotic biosynthesis gene clusters in actinobacteria contain genes for intrinsic self-resistance to the produced antibiotics, and it has been proposed that the antibiotic resistance genes in pathogenic bacteria originated in antibiotic-producing microorganisms. The model actinobacteria Streptomyces clavuligerus produces the β-lactam antibiotic cephamycin C, a class A β-lactamase, and the β lactamases inhibitor clavulanic acid, all of which are encoded in a gene supercluster; in addition, it synthesizes the β-lactamase inhibitory protein BLIP. The secreted clavulanic acid has a synergistic effect with the cephamycin produced by the same strain in the fight against competing microorganisms in its natural habitat. High levels of resistance to cephamycin/cephalosporin in actinobacteria are due to the presence (in their β-lactam clusters) of genes encoding PBPs which bind penicillins but not cephalosporins. We have revised the previously reported cephamycin C and clavulanic acid gene clusters and, in addition, we have searched for novel β-lactam gene clusters in protein databases. Notably, in S. clavuligerus and Nocardia lactamdurans, the β-lactamases are retained in the cell wall and do not affect the intracellular formation of isopenicillin N/penicillin N. The activity of the β-lactamase in S. clavuligerus may be modulated by the β-lactamase inhibitory protein BLIP at the cell-wall level. Analysis of the β-lactam cluster in actinobacteria suggests that these clusters have been moved by horizontal gene transfer between different actinobacteria and have culminated in S. clavuligerus with the organization of an elaborated set of genes designed for fine tuning of antibiotic resistance and cell wall remodeling for the survival of this Streptomyces species. This article is focused specifically on the enigmatic connection between β-lactam biosynthesis and β-lactam resistance mechanisms in the producer actinobacteria.
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Affiliation(s)
| | | | - Paloma Liras
- Departamento de Biología Molecular, Universidad de León, 24071 León, Spain; (J.F.M.); (R.A.-A.)
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Ahmed MS, Lauersen KJ, Ikram S, Li C. Efflux Transporters' Engineering and Their Application in Microbial Production of Heterologous Metabolites. ACS Synth Biol 2021; 10:646-669. [PMID: 33751883 DOI: 10.1021/acssynbio.0c00507] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Metabolic engineering of microbial hosts for the production of heterologous metabolites and biochemicals is an enabling technology to generate meaningful quantities of desired products that may be otherwise difficult to produce by traditional means. Heterologous metabolite production can be restricted by the accumulation of toxic products within the cell. Efflux transport proteins (transporters) provide a potential solution to facilitate the export of these products, mitigate toxic effects, and enhance production. Recent investigations using knockout lines, heterologous expression, and expression profiling of transporters have revealed candidates that can enhance the export of heterologous metabolites from microbial cell systems. Transporter engineering efforts have revealed that some exhibit flexible substrate specificity and may have broader application potentials. In this Review, the major superfamilies of efflux transporters, their mechanistic modes of action, selection of appropriate efflux transporters for desired compounds, and potential transporter engineering strategies are described for potential applications in enhancing engineered microbial metabolite production. Future studies in substrate recognition, heterologous expression, and combinatorial engineering of efflux transporters will assist efforts to enhance heterologous metabolite production in microbial hosts.
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Affiliation(s)
- Muhammad Saad Ahmed
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology (BIT), Beijing 100081, P. R. China
- Department of Biological Sciences, National University of Medical Sciences (NUMS), Abid Majeed Road, The Mall, Rawalpindi 46000, Pakistan
| | - Kyle J. Lauersen
- Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Kingdom of Saudi Arabia
| | - Sana Ikram
- Beijing Higher Institution Engineering Research Center for Food Additives and Ingredients, Beijing Technology & Business University (BTBU), Beijing 100048, P. R. China
| | - Chun Li
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology (BIT), Beijing 100081, P. R. China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, P. R. China
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing 100084, P. R. China
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Homologous expression of lysA encoding diaminopimelic acid (DAP) decarboxylase reveals increased antibiotic production in Streptomyces clavuligerus. Braz J Microbiol 2019; 51:547-556. [PMID: 31833007 DOI: 10.1007/s42770-019-00202-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/27/2019] [Indexed: 10/25/2022] Open
Abstract
lysA gene encoding meso-diaminopimelic acid (DAP) decarboxylase enzyme that catalyzes L-lysine biosynthesis in the aspartate pathway in Streptomyces clavuligerus was overexpressed, and its effects on cephamycin C (CephC), clavulanic acid (CA), and tunicamycin productions were investigated. Multicopy expression of lysA gene under the control of glpF promoter (glpFp) in S. clavuligerus pCOlysA led to higher expression levels ranging from 2- to 6-fold increase at both lysA gene and CephC biosynthetic gene cluster at T36 and T48 of TSBG fermentation. These results accorded well with CephC production. Thus, 1.86- and 3.14-fold higher volumetric as well as 1.26- and 1.71-fold increased specific CephC yields were recorded in S. clavuligerus pCOlysA in comparison with the wild-type and its control strain, respectively, at 48th h. Increasing the expression of lysA provided 4.3 times more tunicamycin yields in the recombinant strain. These findings suggested that lysA overexpression in S. clavuligerus made the strain more productive for CephC and tunicamycin. The results also supported the presence of complex interactions among antibiotic biosynthesis pathways in S. clavuligerus.
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Xie Y, Ma J, Qin X, Li Q, Ju J. Identification and utilization of two important transporters: SgvT1 and SgvT2, for griseoviridin and viridogrisein biosynthesis in Streptomyces griseoviridis. Microb Cell Fact 2017; 16:177. [PMID: 29065880 PMCID: PMC5655939 DOI: 10.1186/s12934-017-0792-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/14/2017] [Indexed: 01/08/2023] Open
Abstract
Background Griseoviridin (GV) and viridogrisein (VG, also referred as etamycin), both biosynthesized by a distinct 105 kb biosynthetic gene cluster (BGC) in Streptomyces griseoviridis NRRL 2427, are a pair of synergistic streptogramin antibiotics and very important in treating infections of many multi-drug resistant microorganisms. Three transporter genes, sgvT1–T3 have been discovered within the 105 kb GV/VG BGC, but the function of these efflux transporters have not been identified. Results In the present study, we have identified the different roles of these three transporters, SgvT1, SgvT2 and SgvT3. SgvT1 is a major facilitator superfamily (MFS) transporter whereas SgvT2 appears to serve as the sole ATP-binding cassette (ABC) transporter within the GV/VG BGC. Both proteins are necessary for efficient GV/VG biosynthesis although SgvT1 plays an especially critical role by averting undesired intracellular GV/VG accumulation during biosynthesis. SgvT3 is an alternative MFS-based transporter that appears to serve as a compensatory transporter in GV/VG biosynthesis. We also have identified the γ-butyrolactone (GBL) signaling pathway as a central regulator of sgvT1–T3 expression. Above all, overexpression of sgvT1 and sgvT2 enhances transmembrane transport leading to steady production of GV/VG in titers ≈ 3-fold greater than seen for the wild-type producer and without any notable disturbances to GV/VG biosynthetic gene expression or antibiotic control. Conclusions Our results shows that SgvT1–T2 are essential and useful in GV/VG biosynthesis and our effort highlight a new and effective strategy by which to better exploit streptogramin-based natural products of which GV and VG are prime examples with clinical potential. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0792-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yunchang Xie
- CAS Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Research Network for Applied Microbiology Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Junying Ma
- CAS Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Research Network for Applied Microbiology Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Xiangjing Qin
- CAS Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Research Network for Applied Microbiology Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Qinglian Li
- CAS Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Research Network for Applied Microbiology Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Jianhua Ju
- CAS Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Research Network for Applied Microbiology Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China. .,College of Earth Sciences, University of Chinese Academy of Sciences, Beijing, 10049, China.
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Martínez-Burgo Y, Álvarez-Álvarez R, Pérez-Redondo R, Liras P. Heterologous expression of Streptomyces clavuligerus ATCC 27064 cephamycin C gene cluster. J Biotechnol 2014; 186:21-9. [DOI: 10.1016/j.jbiotec.2014.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 05/28/2014] [Accepted: 06/02/2014] [Indexed: 12/13/2022]
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Leite CA, Cavallieri AP, Araujo MLGC. Enhancing effect of lysine combined with other compounds on cephamycin C production in Streptomyces clavuligerus. BMC Microbiol 2013; 13:296. [PMID: 24359569 PMCID: PMC3880171 DOI: 10.1186/1471-2180-13-296] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/18/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lysine plays an important role in Streptomyces clavuligerus metabolism; it takes part in its catabolism, via cadaverine, and in its secondary metabolism, in which lysine is converted via 1-piperideine-6-carboxylate to alpha-aminoadipic acid, a beta-lactam antibiotic precursor. The role of lysine as an enhancer of cephamycin C production, when added to production medium at concentrations above 50 mmol l(-1), has already been reported in the literature, with some studies attributing a positive influence to multifunctional diamines, among other compounds. However, there is a lack of research on the combined effect of these compounds on antibiotic production. RESULTS Results from experimental design-based tests were used to conduct response surface-based optimization studies in order to investigate the synergistic effect of combining lysine with cadaverine, putrescine, 1,3-diaminopropane, or alpha-aminoadipic acid on cephamycin C volumetric production. Lysine combined with cadaverine influenced production positively, but only at low lysine concentrations. On the whole, higher putrescine concentrations (0.4 g l(-1)) affected negatively cephamycin C volumetric production. In comparison to culture media containing only lysine as additive, combinations of this amino acid with alpha-aminoadipic acid or 1,3-diaminopropane increased cephamycin C production by more than 100%. CONCLUSION This study demonstrated that different combinations of lysine with diamines or lysine with alpha-aminoadipic acid engender significant differences with respect to antibiotic volumetric production, with emphasis on the benefits observed for lysine combined with alpha-aminoadipic acid or 1,3-diaminopropane. This increase is explained by mathematical models and demonstrated by means of bioreactor cultivations. Moreover, it is consistent with the positive influence of these compounds on lysine conversion to alpha-aminoadipic acid, a limiting step in cephamycin C production.
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Affiliation(s)
- Carla A Leite
- Department of Biochemistry and Technological Chemistry, UNESP - São Paulo State University, Institute of Chemistry, 14800-900 Araraquara, SP, Brazil
| | - André P Cavallieri
- Department of Biochemistry and Technological Chemistry, UNESP - São Paulo State University, Institute of Chemistry, 14800-900 Araraquara, SP, Brazil
| | - Maria L G C Araujo
- Department of Biochemistry and Technological Chemistry, UNESP - São Paulo State University, Institute of Chemistry, 14800-900 Araraquara, SP, Brazil
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Hallen A, Jamie JF, Cooper AJL. Lysine metabolism in mammalian brain: an update on the importance of recent discoveries. Amino Acids 2013. [PMID: 24043460 DOI: 10.1007/s00726-013-1590-1591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The lysine catabolism pathway differs in adult mammalian brain from that in extracerebral tissues. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. The two pathways converge at the level of ∆(1)-piperideine-6-carboxylate (P6C), which is in equilibrium with its open-chain aldehyde form, namely, α-aminoadipate δ-semialdehyde (AAS). A unique feature of the pipecolate pathway is the formation of the cyclic ketimine intermediate ∆(1)-piperideine-2-carboxylate (P2C) and its reduced metabolite L-pipecolate. A cerebral ketimine reductase (KR) has recently been identified that catalyzes the reduction of P2C to L-pipecolate. The discovery that this KR, which is capable of reducing not only P2C but also other cyclic imines, is identical to a previously well-described thyroid hormone-binding protein [μ-crystallin (CRYM)], may hold the key to understanding the biological relevance of the pipecolate pathway and its importance in the brain. The finding that the KR activity of CRYM is strongly inhibited by the thyroid hormone 3,5,3'-triiodothyronine (T3) has far-reaching biomedical and clinical implications. The inter-relationship between tryptophan and lysine catabolic pathways is discussed in the context of shared degradative enzymes and also potential regulation by thyroid hormones. This review traces the discoveries of enzymes involved in lysine metabolism in mammalian brain. However, there still remain unanswered questions as regards the importance of the pipecolate pathway in normal or diseased brain, including the nature of the first step in the pathway and the relationship of the pipecolate pathway to the tryptophan degradation pathway.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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Hallen A, Jamie JF, Cooper AJL. Lysine metabolism in mammalian brain: an update on the importance of recent discoveries. Amino Acids 2013; 45:1249-72. [PMID: 24043460 DOI: 10.1007/s00726-013-1590-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 08/29/2013] [Indexed: 12/23/2022]
Abstract
The lysine catabolism pathway differs in adult mammalian brain from that in extracerebral tissues. The saccharopine pathway is the predominant lysine degradative pathway in extracerebral tissues, whereas the pipecolate pathway predominates in adult brain. The two pathways converge at the level of ∆(1)-piperideine-6-carboxylate (P6C), which is in equilibrium with its open-chain aldehyde form, namely, α-aminoadipate δ-semialdehyde (AAS). A unique feature of the pipecolate pathway is the formation of the cyclic ketimine intermediate ∆(1)-piperideine-2-carboxylate (P2C) and its reduced metabolite L-pipecolate. A cerebral ketimine reductase (KR) has recently been identified that catalyzes the reduction of P2C to L-pipecolate. The discovery that this KR, which is capable of reducing not only P2C but also other cyclic imines, is identical to a previously well-described thyroid hormone-binding protein [μ-crystallin (CRYM)], may hold the key to understanding the biological relevance of the pipecolate pathway and its importance in the brain. The finding that the KR activity of CRYM is strongly inhibited by the thyroid hormone 3,5,3'-triiodothyronine (T3) has far-reaching biomedical and clinical implications. The inter-relationship between tryptophan and lysine catabolic pathways is discussed in the context of shared degradative enzymes and also potential regulation by thyroid hormones. This review traces the discoveries of enzymes involved in lysine metabolism in mammalian brain. However, there still remain unanswered questions as regards the importance of the pipecolate pathway in normal or diseased brain, including the nature of the first step in the pathway and the relationship of the pipecolate pathway to the tryptophan degradation pathway.
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Affiliation(s)
- André Hallen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Balaclava Road, North Ryde, NSW, 2109, Australia,
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Kurt A, Álvarez-Álvarez R, Liras P, Özcengiz G. Role of the cmcH–ccaR intergenic region and ccaR overexpression in cephamycin C biosynthesis in Streptomyces clavuligerus. Appl Microbiol Biotechnol 2013; 97:5869-80. [DOI: 10.1007/s00253-013-4721-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 01/14/2013] [Accepted: 01/15/2013] [Indexed: 01/08/2023]
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Hamed RB, Gomez-Castellanos JR, Henry L, Ducho C, McDonough MA, Schofield CJ. The enzymes of β-lactam biosynthesis. Nat Prod Rep 2013; 30:21-107. [DOI: 10.1039/c2np20065a] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Isobe K. Enzymes responsible for metabolism of Nα-benzyloxycarbonyl-L-lysine in microorganisms. N Biotechnol 2010; 27:751-4. [PMID: 20460177 DOI: 10.1016/j.nbt.2010.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Revised: 04/08/2010] [Accepted: 05/02/2010] [Indexed: 11/29/2022]
Abstract
The present paper reviews the enzymes catalyzing conversion of Nα-benzyloxycarbonyl-L-lysine (Nα-Z-L-lysine) to Nα-benzyloxycarbonyl-L-aminoadipic acid (Nα-Z-L-AAA) in fungal and bacterial strains. Aspergillus niger AKU 3302 and Rhodococcus sp. AIU Z-35-1 converted Nα-Z-L-lysine to Nα-Z-L-AAA via Nα-benzyloxycarbonyl-L-aminoadipate-δ-semialdehyde (Nα-Z-L-AASA). However, different enzyme combinations were involved in the Nα-Z-L-lysine metabolism of both strains. A. niger strain converted Nα-Z-L-lysine to Nα-Z-L-AASA by amine oxidase, and the resulting Nα-Z-L-AASA was converted to Nα-Z-L-AAA by an aldehyde oxidase. In the Rhodococcus strain, conversion of Nα-Z-L-lysine to Nα-Z-L-AASA was catalyzed by l-specific amino acid oxidase. The resulting Nα-Z-L-AASA was converted to Nα-Z-L-AAA by an aldehyde dehydrogenase. The present paper also describes characteristics of new enzymes obtained from those strains.
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Affiliation(s)
- Kimiyasu Isobe
- Department of Biological Chemistry and Food Science, Iwate University, Morioka 020-8550, Japan.
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Cundliffe E, Demain AL. Avoidance of suicide in antibiotic-producing microbes. J Ind Microbiol Biotechnol 2010; 37:643-72. [PMID: 20446033 DOI: 10.1007/s10295-010-0721-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 03/30/2010] [Indexed: 11/29/2022]
Abstract
Many microbes synthesize potentially autotoxic antibiotics, mainly as secondary metabolites, against which they need to protect themselves. This is done in various ways, ranging from target-based strategies (i.e. modification of normal drug receptors or de novo synthesis of the latter in drug-resistant form) to the adoption of metabolic shielding and/or efflux strategies that prevent drug-target interactions. These self-defence mechanisms have been studied most intensively in antibiotic-producing prokaryotes, of which the most prolific are the actinomycetes. Only a few documented examples pertain to lower eukaryotes while higher organisms have hardly been addressed in this context. Thus, many plant alkaloids, variously described as herbivore repellents or nitrogen excretion devices, are truly antibiotics-even if toxic to humans. As just one example, bulbs of Narcissus spp. (including the King Alfred daffodil) accumulate narciclasine that binds to the larger subunit of the eukaryotic ribosome and inhibits peptide bond formation. However, ribosomes in the Amaryllidaceae have not been tested for possible resistance to narciclasine and other alkaloids. Clearly, the prevalence of suicide avoidance is likely to extend well beyond the remit of the present article.
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Affiliation(s)
- Eric Cundliffe
- Department of Biochemistry, University of Leicester, Leicester, LE1 9HN, UK.
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Genome-minimized Streptomyces host for the heterologous expression of secondary metabolism. Proc Natl Acad Sci U S A 2010; 107:2646-51. [PMID: 20133795 DOI: 10.1073/pnas.0914833107] [Citation(s) in RCA: 368] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To construct a versatile model host for heterologous expression of genes encoding secondary metabolite biosynthesis, the genome of the industrial microorganism Streptomyces avermitilis was systematically deleted to remove nonessential genes. A region of more than 1.4 Mb was deleted stepwise from the 9.02-Mb S. avermitilis linear chromosome to generate a series of defined deletion mutants, corresponding to 83.12-81.46% of the wild-type chromosome, that did not produce any of the major endogenous secondary metabolites found in the parent strain. The suitability of the mutants as hosts for efficient production of foreign metabolites was shown by heterologous expression of three different exogenous biosynthetic gene clusters encoding the biosynthesis of streptomycin (from S. griseus Institute for Fermentation, Osaka [IFO] 13350), cephamycin C (from S. clavuligerus American type culture collection (ATCC) 27064), and pladienolide (from S. platensis Mer-11107). Both streptomycin and cephamycin C were efficiently produced by individual transformants at levels higher than those of the native-producing species. Although pladienolide was not produced by a deletion mutant transformed with the corresponding intact biosynthetic gene cluster, production of the macrolide was enabled by introduction of an extra copy of the regulatory gene pldR expressed under control of an alternative promoter. Another mutant optimized for terpenoid production efficiently produced the plant terpenoid intermediate, amorpha-4,11-diene, by introduction of a synthetic gene optimized for Streptomyces codon usage. These findings highlight the strength and flexibility of engineered S. avermitilis as a model host for heterologous gene expression, resulting in the production of exogenous natural and unnatural metabolites.
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15
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Regulatory mechanisms controlling antibiotic production in Streptomyces clavuligerus. J Ind Microbiol Biotechnol 2008; 35:667-76. [DOI: 10.1007/s10295-008-0351-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Accepted: 03/31/2008] [Indexed: 11/25/2022]
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Purification and characterization of a dehydrogenase catalyzing conversion of N alpha-benzyloxycarbonyl-L-aminoadipic-delta-semialdehyde to N alpha-benzyloxycarbonyl-L-aminoadipic acid from rhodococcus sp. AIU Z-35-1. J Biosci Bioeng 2008; 104:398-402. [PMID: 18086440 DOI: 10.1263/jbb.104.398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 08/06/2007] [Indexed: 11/17/2022]
Abstract
The enzyme catalyzing conversion of N alpha-benzyloxycarbonyl-L-aminoadipic-delta-semialdehyde (N alpha-Z-L-AASA) to N alpha-benzyloxycarbonyl-L-aminoadipic acid (N alpha-Z-L-AAA) in Rhodococcus sp. AIU Z-35-1 was identified, and its characteristics were revealed. This reaction was catalyzed by a dehydrogenase with a molecular mass of 59 kDa. The dehydrogenase exhibited enzyme activity on not only N alpha-Z-L-AASA but also N alpha-Z-D-AASA and short chain aliphatic aldehydes, but not on aromatic aldehydes and alcohols. The apparent Km values for N alpha-Z-L-AASA, N alpha-Z-D-AASA and NAD+ were estimated to be 3.8 mM, 14.1 mM and 0.16 mM, respectively. The NH2 terminal amino acid sequence of this enzyme exhibited a similarity to those of a piperidein-6-carboxylate dehydrogenase from Streptomyces clavuligerus and a putative dehydrogenase from Rhodococcus sp. RHA 1, but not to those of other microbial aldehyde dehydrogenases.
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Alexander DC, Anders CL, Lee L, Jensen SE. pcd mutants of Streptomyces clavuligerus still produce cephamycin C. J Bacteriol 2007; 189:5867-74. [PMID: 17573474 PMCID: PMC1952048 DOI: 10.1128/jb.00712-07] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biosynthesis of cephamycin C in Streptomyces clavuligerus involves the initial conversion of lysine to alpha-aminoadipic acid. Lysine-6-aminotransferase and piperideine-6-carboxylate dehydrogenase carry out this two-step reaction, and genes encoding each of these enzymes are found within the cephamycin C gene cluster. However, while mutation of the lat gene causes complete loss of cephamycin production, pcd mutants still produce cephamycin at 30% to 70% of wild-type levels. Cephamycin production by pcd mutants could be restored to wild-type levels either by supplementation of the growth medium with alpha-aminoadipic acid or by complementation of the mutation with an intact copy of the pcd gene. Neither heterologous PCR nor Southern analyses showed any evidence for the presence of a second pcd gene. Furthermore, cell extracts from pcd mutants lack detectable PCD activity. Cephamycin production in the absence of detectable PCD activity suggests that S. clavuligerus must have some alternate means of producing the aminoadipyl-cysteinyl-valine needed for cephamycin biosynthesis.
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Affiliation(s)
- Dylan C Alexander
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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18
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Clayton PT. B6-responsive disorders: a model of vitamin dependency. J Inherit Metab Dis 2006; 29:317-26. [PMID: 16763894 DOI: 10.1007/s10545-005-0243-2] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 02/09/2006] [Indexed: 10/24/2022]
Abstract
Pyridoxal phosphate is the cofactor for over 100 enzyme-catalysed reactions in the body, including many involved in the synthesis or catabolism of neurotransmitters. Inadequate levels of pyridoxal phosphate in the brain cause neurological dysfunction, particularly epilepsy. There are several different mechanisms that lead to an increased requirement for pyridoxine and/or pyridoxal phosphate. These include: (i) inborn errors affecting the pathways of B(6) vitamer metabolism; (ii) inborn errors that lead to accumulation of small molecules that react with pyridoxal phosphate and inactivate it; (iii) drugs that react with pyridoxal phosphate; (iv) coeliac disease, which is thought to lead to malabsorption of B(6) vitamers; (v) renal dialysis, which leads to increased losses of B(6) vitamers from the circulation; (vi) drugs that affect the metabolism of B(6) vitamers; and (vii) inborn errors affecting specific pyridoxal phosphate-dependent enzymes. The last show a very variable degree of pyridoxine responsiveness, from 90% in X-linked sideroblastic anaemia (delta-aminolevulinate synthase deficiency) through 50% in homocystinuria (cystathionine beta-synthase deficiency) to 5% in ornithinaemia with gyrate atrophy (ornithine delta-aminotransferase deficiency). The possible role of pyridoxal phosphate as a chaperone during folding of nascent enzymes is discussed. High-dose pyridoxine or pyridoxal phosphate may have deleterious side-effects (particularly peripheral neuropathy with pyridoxine) and this must be considered in treatment regimes. None the less, in some patients, particularly infants with intractable epilepsy, treatment with pyridoxine or pyridoxal phosphate can be life-saving, and in other infants with inborn errors of metabolism B(6) treatment can be extremely beneficial.
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Affiliation(s)
- Peter T Clayton
- Biochemistry, Endocrinology and Metabolism, Institute of Child Health, 30 Guilford St, London, WC1N 1 EH, UK.
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19
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Yamazaki Y, Danelishvili L, Wu M, Macnab M, Bermudez LE. Mycobacterium avium genes associated with the ability to form a biofilm. Appl Environ Microbiol 2006; 72:819-25. [PMID: 16391123 PMCID: PMC1352297 DOI: 10.1128/aem.72.1.819-825.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium avium is widely distributed in the environment, and it is chiefly found in water and soil. M. avium, as well as Mycobacterium smegmatis, has been recognized to produce a biofilm or biofilm-like structure. We screened an M. avium green fluorescent protein (GFP) promoter library in M. smegmatis for genes involved in biofilm formation on polyvinyl chloride (PVC) plates. Clones associated with increased GFP expression > or =2.0-fold over the baseline were sequenced. Seventeen genes, most encoding proteins of the tricarboxylic acid (TCA) cycle and GDP-mannose and fatty acid biosynthesis, were identified. Their regulation in M. avium was confirmed by examining the expression of a set of genes by real-time PCR after incubation on PVC plates. In addition, screening of 2,000 clones of a transposon mutant bank constructed using M. avium strain A5, a mycobacterial strain with the ability to produce large amounts of biofilm, revealed four mutants with an impaired ability to form biofilm. Genes interrupted by transposons were homologues of M. tuberculosis 6-oxodehydrogenase (sucA), enzymes of the TCA cycle, protein synthetase (pstB), enzymes of glycopeptidolipid (GPL) synthesis, and Rv1565c (a hypothetical membrane protein). In conclusion, it appears that GPL biosynthesis, including the GDP-mannose biosynthesis pathway, is the most important pathway involved in the production of M. avium biofilm.
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Affiliation(s)
- Yoshitaka Yamazaki
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, Corvallis, OR 97331, USA
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20
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Ishida K, Hung TV, Liou K, Lee HC, Shin CH, Sohng JK. Characterization of pbpA and pbp2 Encoding Penicillin-binding Proteins Located on the Downstream of Clavulanic Acid Gene Cluster in Streptomyces clavuligerus. Biotechnol Lett 2006; 28:409-17. [PMID: 16614907 DOI: 10.1007/s10529-005-6071-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Accepted: 12/14/2005] [Indexed: 10/24/2022]
Abstract
Two genes, pbpA (orf18) and pbp2 (orf19) located on the downstream of clavulanic acid (CA) gene cluster of Streptomyces clavuligerus were cloned into pET-28a(+), and confirmed to encode a family of high molecular-weight penicillin-binding proteins (PBPs). Both genes were amplified from genomic DNA by PCR and expressed in E. coli BL21 (DE3). Hydropathy plots of the proteins revealed a single stretch of hydrophobic amino acids indicating them to be transmembrane proteins. Pbp2 had lower affinity to penicillin G compared to PbpA, and was essential to the cell growth in contrast to PbpA.
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Affiliation(s)
- Kenji Ishida
- Institute of Biomolecule Reconstruction, Sun Moon University, 100, Kalsanri, Tangjeonmyun, 336-708, Asansi, Chungnam, Korea
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21
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Mills PB, Struys E, Jakobs C, Plecko B, Baxter P, Baumgartner M, Willemsen MAAP, Omran H, Tacke U, Uhlenberg B, Weschke B, Clayton PT. Mutations in antiquitin in individuals with pyridoxine-dependent seizures. Nat Med 2006; 12:307-9. [PMID: 16491085 DOI: 10.1038/nm1366] [Citation(s) in RCA: 350] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Accepted: 01/10/2006] [Indexed: 11/09/2022]
Abstract
We show here that children with pyridoxine-dependent seizures (PDS) have mutations in the ALDH7A1 gene, which encodes antiquitin; these mutations abolish the activity of antiquitin as a delta1-piperideine-6-carboxylate (P6C)-alpha-aminoadipic semialdehyde (alpha-AASA) dehydrogenase. The accumulating P6C inactivates pyridoxal 5'-phosphate (PLP) by forming a Knoevenagel condensation product. Measurement of urinary alpha-AASA provides a simple way of confirming the diagnosis of PDS and ALDH7A1 gene analysis provides a means for prenatal diagnosis.
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Affiliation(s)
- Philippa B Mills
- Institute of Child Health, University College London with Great Ormond Street Hospital for Children National Health Service Trust, 30 Guilford Street, London, UK
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22
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Naranjo L, Lamas-Maceiras M, Ullán RV, Campoy S, Teijeira F, Casqueiro J, Martín JF. Characterization of the oat1 gene of Penicillium chrysogenum encoding an omega-aminotransferase: induction by L-lysine, L-ornithine and L-arginine and repression by ammonium. Mol Genet Genomics 2005; 274:283-94. [PMID: 16163487 DOI: 10.1007/s00438-005-0019-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Accepted: 06/11/2005] [Indexed: 11/29/2022]
Abstract
The Penicillium chrysogenum oat1 gene, which encodes a class III omega-aminotransferase, was cloned and characterized. This enzyme converts lysine into 2-aminoadipic semialdehyde, and plays an important role in the biosynthesis of 2-aminoadipic acid, a precursor of penicillin and other beta-lactam antibiotics. The enzyme is related to ornithine-5-aminotransferases and to the lysine-6-aminotransferases encoded by the lat genes found in bacterial cephamycin gene clusters. Expression of oat1 is induced by lysine, ornithine and arginine, and repressed by ammonium ions. AreA-binding GATA and GATT sequences involved in regulation by ammonium, and an 8-bp direct repeat associated with arginine induction in Emericella (Aspergillus nidulans and Saccharomyces cerevisiae, were found in the oat1 promoter region. Deletion of the oat1 gene resulted in the loss of omega-aminotransferase activity. The null mutants were unable to grow on ornithine or arginine as sole nitrogen sources and showed reduced growth on lysine. Complementation of the null mutant with the oat1 gene restored normal levels of omega-aminotransferase activity and the ability to grow on ornithine, arginine and lysine. The role of the oat1 gene in the biosynthesis of 2-aminoadipic acid is discussed.
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Affiliation(s)
- Leopoldo Naranjo
- Instituto de Biotecnología de León (INBIOTEC), Parque Científico de León, Spain
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23
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Valmaseda EMMD, Campoy S, Naranjo L, Casqueiro J, Martín JF. Lysine is catabolized to 2-aminoadipic acid in Penicillium chrysogenum by an omega-aminotransferase and to saccharopine by a lysine 2-ketoglutarate reductase. Characterization of the omega-aminotransferase. Mol Genet Genomics 2005; 274:272-82. [PMID: 16049680 DOI: 10.1007/s00438-005-0018-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Accepted: 05/05/2005] [Indexed: 10/25/2022]
Abstract
The biosynthesis and catabolism of lysine in Penicillium chrysogenum is of great interest because these pathways provide 2-aminoadipic acid, a precursor of the tripeptide delta-L-2-aminoadipyl-L-cysteinyl-D-valine that is an intermediate in penicillin biosynthesis. In vivo conversion of labelled L-lysine into two different intermediates was demonstrated by HPLC analysis of the intracellular amino acid pool. L-lysine is catabolized to 2-aminoadipic acid by an omega-aminotransferase and to saccharopine by a lysine-2-ketoglutarate reductase. In lysine-containing medium both activities were expressed at high levels, but the omega-aminotransferase activity, in particular, decreased sharply when ammonium was used as the nitrogen source. The omega-aminotransferase was partially purified, and found to accept L-lysine, L-ornithine and, to a lesser extent, N-acetyl-L-lysine as amino-group donors. 2-Ketoglutarate, 2-ketoadipate and, to a lesser extent, pyruvate served as amino group acceptors. This pattern suggests that this enzyme, previously designated as a lysine-6-aminotransferase, is actually an omega-aminotransferase. When 2-ketoadipate is used as substrate, the reaction product is 2-aminoadipic acid, which contributes to the pool of this intermediate available for penicillin biosynthesis. The N-terminal end of the purified 45-kDa omega-aminotransferase was sequenced and was found to be similar to the corresponding segment of the OAT1 protein of Emericella (Aspergillus) nidulans. This information was used to clone the gene encoding this enzyme.
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Affiliation(s)
- E M Martín de Valmaseda
- Area de Microbiología, Fac. CC. Biológicas y Ambientales, Universidad de León, Campus de Vegazana, s/n, Spain
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24
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Martín JF, Casqueiro J, Liras P. Secretion systems for secondary metabolites: how producer cells send out messages of intercellular communication. Curr Opin Microbiol 2005; 8:282-93. [PMID: 15939351 DOI: 10.1016/j.mib.2005.04.009] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 04/22/2005] [Indexed: 11/23/2022]
Abstract
Many secondary metabolites (e.g. antibiotics and mycotoxins) are toxic to the microorganisms that produce them. The clusters of genes that are responsible for the biosynthesis of secondary metabolites frequently contain genes for resistance to these toxic metabolites, such as different types of multiple drug resistance systems, to avoid suicide of the producer strains. Recently there has been research into the efflux systems of secondary metabolites in bacteria and in filamentous fungi, such as the large number of ATP-binding cassette transporters found in antibiotic-producing Streptomyces species and that are involved in penicillin secretion in Penicillium chrysogenum. A different group of efflux systems, the major facilitator superfamily exporters, occur very frequently in a variety of bacteria that produce pigments or antibiotics (e.g. the cephamycin and thienamycin producers) and in filamentous fungi that produce mycotoxins. Such efflux systems include the CefT exporters that mediate cephalosporin secretion in Acremonium chrysogenum. The evolutionary origin of these efflux systems and their relationship with current resistance determinants in pathogenic bacteria has been analyzed. Genetic improvement of the secretion systems of secondary metabolites in the producer strain has important industrial applications.
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Affiliation(s)
- Juan F Martín
- Area de Microbiología, Facultad de Ciencias Biológicas y Ambientales, Campus de Vegazana, s/n, 24071 León, Spain.
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25
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Santamarta I, Rodríguez-García A, Pérez-Redondo R, Martín JF, Liras P. CcaR is an autoregulatory protein that binds to the ccaR and cefD-cmcI promoters of the cephamycin C-clavulanic acid cluster in Streptomyces clavuligerus. J Bacteriol 2002; 184:3106-13. [PMID: 12003953 PMCID: PMC135043 DOI: 10.1128/jb.184.11.3106-3113.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The putative regulatory CcaR protein, which is encoded in the beta-lactam supercluster of Streptomyces clavuligerus, has been partially purified by ammonium sulfate precipitation and heparin affinity chromatography. In addition, it was expressed in Escherichia coli, purified as a His-tagged recombinant protein (rCcaR), and used to raise anti-rCcaR antibodies. The partially purified CcaR protein from S. clavuligerus was able to bind DNA fragments containing the promoter regions of the ccaR gene itself and the bidirectional cefD-cmcI promoter region. In contrast, CcaR did not bind to DNA fragments with the promoter regions of other genes of the cephamycin-clavulanic acid supercluster including lat, blp, claR, car-cyp, and the unlinked argR gene. The DNA shifts obtained with CcaR were prevented by anti-rCcaR immunoglobulin G (IgG) antibodies but not by anti-rabbit IgG antibodies. ccaR and the bidirectional cefD-cmcI promoter region were fused to the xylE reporter gene and expressed in Streptomyces lividans and S. clavuligerus. These constructs produced low catechol dioxygenase activity in the absence of CcaR; activity was increased 1.7- to 4.6-fold in cultures expressing CcaR. Amplification of the ccaR promoter region lacking its coding sequence in a high-copy-number plasmid in S. clavuligerus ATCC 27064 resulted in a reduced production of cephamycin C and clavulanic acid, by 12 to 20% and 40 to 60%, respectively, due to titration of the CcaR regulator. These findings confirm that CcaR is a positively acting autoregulatory protein able to bind to its own promoter as well as to the cefD-cmcI bidirectional promoter region.
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Affiliation(s)
- Irene Santamarta
- Area de Microbiología, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain
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26
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Mellado E, Lorenzana LM, Rodrı Guez-Sáiz M, Dı Ez B, Liras P, Barredo JL. The clavulanic acid biosynthetic cluster of Streptomyces clavuligerus: genetic organization of the region upstream of the car gene. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1427-1438. [PMID: 11988517 DOI: 10.1099/00221287-148-5-1427] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The genetic organization of the region upstream of the car gene of the clavulanic acid biosynthetic gene cluster of Streptomyces clavuligerus has been determined. Sequence analysis of a 12.1 kb region revealed the presence of 10 ORFs whose putative functions, according to database searches, are discussed. Three co-transcriptional units are proposed: ORF10-11, ORF12-13 and ORF15-16-17-18. Potential transcriptional terminators were identified downstream of ORF11 (fd) and ORF15. Targeted disruption of ORF10 (cyp) gave rise to transformants unable to produce clavulanic acid, but with a considerably higher production of cephamycin C. Transformants inactivated at ORF14 had a remarkably lower production of clavulanic acid and similar production of cephamycin C. Significant improvements of clavulanic acid production, associated with a drop in cephamycin C biosynthesis, were obtained with transformants of S. clavuligerus harbouring multiple copies of plasmids carrying different constructions from the ORF10-14 region. This information can be used to guide strain improvement programs, blending random mutagenesis and molecular cloning, to optimize the yield of clavulanic acid.
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Affiliation(s)
- Encarnación Mellado
- Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1
| | - Luis Miguel Lorenzana
- Área de Microbiologı́a, Facultad de Biologı́a, Universidad de León, 24071 León, Spain2
| | - Marta Rodrı Guez-Sáiz
- Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1
| | - Bruno Dı Ez
- Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1
| | - Paloma Liras
- Área de Microbiologı́a, Facultad de Biologı́a, Universidad de León, 24071 León, Spain2
| | - José Luis Barredo
- Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1
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27
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Hernándo-Rico V, Martı N JF, Santamarta I, Liras P. Structure of the ask-asd operon and formation of aspartokinase subunits in the cephamycin producer 'Amycolatopsis lactamdurans'. MICROBIOLOGY (READING, ENGLAND) 2001; 147:1547-1555. [PMID: 11390685 DOI: 10.1099/00221287-147-6-1547] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The first two genes of the lysine pathway are closely linked forming a transcriptional operon in the cephamycin producer 'Amycolatopsis lactamdurans'. The asd gene, encoding the enzyme aspartic semialdehyde dehydrogenase, has been cloned by complementation of Escherichia coli asd mutants. It encodes a protein of 355 aa with a deduced M(r) of 37109. The ask gene encoding the aspartokinase (Ask) is located upstream of the asd gene as shown by determination of Ask activity conferred to E. coli transformants. asd and ask are separated by 2 nt and are transcribed in a bicistronic 2.6 kb mRNA. As occurs in corynebacteria, the presence of a ribosome-binding site within the ask sequence suggests that this ORF encodes two overlapping proteins, Askalpha of 421 aa and M(r) 44108, and Askbeta of 172 aa and M(r) 18145. The formation of both subunits of Ask from a single gene (ask) was confirmed by using antibodies against the C-terminal end of Ask which is identical in both subunits. Ask activity of 'A. lactamdurans' is regulated by the concerted action of lysine plus threonine and this inhibition is abolished in E. coli transformants containing Ser(301) to Tyr, or Gly(345) to Asp mutations of the 'A. lactamdurans' ask gene.
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Affiliation(s)
- Victor Hernándo-Rico
- Area de Microbiologı́a, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain1
| | - Juan F Martı N
- Area de Microbiologı́a, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain1
| | - Irene Santamarta
- Area de Microbiologı́a, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain1
| | - Paloma Liras
- Area de Microbiologı́a, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071 León, Spain1
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28
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Paradkar AS, Mosher RH, Anders C, Griffin A, Griffin J, Hughes C, Greaves P, Barton B, Jensen SE. Applications of gene replacement technology to Streptomyces clavuligerus strain development for clavulanic acid production. Appl Environ Microbiol 2001; 67:2292-7. [PMID: 11319114 PMCID: PMC92869 DOI: 10.1128/aem.67.5.2292-2297.2001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cephamycin C production was blocked in wild-type cultures of the clavulanic acid-producing organism Streptomyces clavuligerus by targeted disruption of the gene (lat) encoding lysine epsilon-aminotransferase. Specific production of clavulanic acid increased in the lat mutants derived from the wild-type strain by 2- to 2.5-fold. Similar beneficial effects on clavulanic acid production were noted in previous studies when gene disruption was used to block the production of the non-clavulanic acid clavams produced by S. clavuligerus. Therefore, mutations in lat and in cvm1, a gene involved in clavam production, were introduced into a high-titer industrial strain of S. clavuligerus to create a double mutant with defects in production of both cephamycin C and clavams. Production of both cephamycin C and non-clavulanic acid clavams was eliminated in the double mutant, and clavulanic acid titers increased about 10% relative to those of the parental strain. This represents the first report of the successful use of genetic engineering to eliminate undesirable metabolic pathways in an industrial strain used for the production of an antibiotic important in human medicine.
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Affiliation(s)
- A S Paradkar
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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29
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Alexander DC, Brumlik MJ, Lee L, Jensen SE. Early cephamycin biosynthetic genes are expressed from a polycistronic transcript in Streptomyces clavuligerus. J Bacteriol 2000; 182:348-56. [PMID: 10629179 PMCID: PMC94282 DOI: 10.1128/jb.182.2.348-356.2000] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A polycistronic transcript that is initiated at the lat promoter has been implicated in the expression of the genes involved in early steps of cephamycin C biosynthesis in Streptomyces clavuligerus. pcbC is also expressed as a monocistronic transcript from its own promoter. However, an alternative interpretation involving expression via three separate yet interdependent transcripts has also been proposed. To distinguish between these possibilities, mutants lacking the lat promoter and containing a transcription terminator within the lat gene (Deltalat::tsr/term mutants) were created. This mutation eliminated the production of lysine-epsilon-aminotransferase (the lat gene product) but also affected the expression of downstream genes, indicating an operon arrangement. Production of delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS) (the pcbAB gene product) was eliminated in Deltalat::tsr/term mutants, while production of isopenicillin N synthase (IPNS) (the pcbC gene product) was greatly reduced. The provision of alpha-aminoadipate to the Deltalat::tsr/term mutants, either via exogenous feeding or via lat gene complementation, did not restore production of ACVS or IPNS. Analysis of RNA isolated from the Deltalat::tsr/term mutants confirmed that the polycistronic transcript was absent but also indicated that monocistronic pcbC transcript levels were greatly decreased. In contrast, Deltalat mutants created by in-frame internal deletion of lat maintained the polycistronic transcript and allowed production of wild-type levels of both ACVS and IPNS.
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Affiliation(s)
- D C Alexander
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
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30
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Leitão AL, Enguita FJ, De La Fuente JL, Liras P, Martin JF. Inducing effect of diamines on transcription of the cephamycin C genes from the lat and pcbAB promoters in Nocardia lactamdurans. J Bacteriol 1999; 181:2379-84. [PMID: 10197999 PMCID: PMC93661 DOI: 10.1128/jb.181.8.2379-2384.1999] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/1998] [Accepted: 01/25/1999] [Indexed: 11/20/2022] Open
Abstract
The diamines putrescine, cadaverine, and diaminopropane stimulate cephamycin biosynthesis in Nocardia lactamdurans, in shake flasks and fermentors, without altering cell growth. Intracellular levels of the P7 protein (a component of the methoxylation system involved in cephamycin biosynthesis) were increased by diaminopropane, as shown by immunoblotting studies. Lysine-6-aminotransferase and piperideine-6-carboxylate dehydrogenase activities involved in biosynthesis of the alpha-aminoadipic acid precursor were also greatly stimulated. The diamine stimulatory effect is exerted at the transcriptional level, as shown by low-resolution S1 protection studies. The transcript corresponding to the pcbAB gene and to a lesser extent also the lat transcript were significantly increased in diaminopropane-supplemented cultures, whereas transcription from the cefD promoter was not affected. Coupling of the lat and pcbAB promoters to the reporter xylE gene showed that expression from the lat and pcbAB promoters was increased by addition of diaminopropane in Streptomyces lividans. Intracellular accumulation of diamines in Nocardia may be a signal to trigger antibiotic production.
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Affiliation(s)
- A L Leitão
- Institute of Biotechnology, University of León, 24006 León, Spain
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