1
|
Chen X, Sun Y, Wang S, Ying K, Xiao L, Liu K, Zuo X, He J. Identification of a novel structure-specific endonuclease AziN that contributes to the repair of azinomycin B-mediated DNA interstrand crosslinks. Nucleic Acids Res 2020; 48:709-718. [PMID: 31713613 PMCID: PMC7145581 DOI: 10.1093/nar/gkz1067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 10/11/2019] [Accepted: 10/30/2019] [Indexed: 11/25/2022] Open
Abstract
DNA interstrand crosslinks (ICLs) induced by the highly genotoxic agent azinomycin B (AZB) can cause severe perturbation of DNA structure and even cell death. However, Streptomyces sahachiroi, the strain that produces AZB, seems almost impervious to this danger because of its diverse and distinctive self-protection machineries. Here, we report the identification of a novel endonuclease-like gene aziN that contributes to drug self-protection in S. sahachiroi. AziN expression conferred AZB resistance on native and heterologous host strains. The specific binding reaction between AziN and AZB was also verified in accordance with its homology to drug binding proteins, but no drug sequestering and deactivating effects could be detected. Intriguingly, due to the high affinity with the drug, AziN was discovered to exhibit specific recognition and binding capacity with AZB-mediated ICL structures, further inducing DNA strand breakage. Subsequent in vitro assays demonstrated the structure-specific endonuclease activity of AziN, which cuts both damaged strands at specific sites around AZB-ICLs. Unravelling the nuclease activity of AziN provides a good entrance point to illuminate the complex mechanisms of AZB-ICL repair.
Collapse
Affiliation(s)
- Xiaorong Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yuedi Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shan Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Kun Ying
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Le Xiao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiuli Zuo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jing He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| |
Collapse
|
2
|
Ogawara H. Comparison of Antibiotic Resistance Mechanisms in Antibiotic-Producing and Pathogenic Bacteria. Molecules 2019; 24:E3430. [PMID: 31546630 PMCID: PMC6804068 DOI: 10.3390/molecules24193430] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/18/2019] [Accepted: 09/20/2019] [Indexed: 12/13/2022] Open
Abstract
Antibiotic resistance poses a tremendous threat to human health. To overcome this problem, it is essential to know the mechanism of antibiotic resistance in antibiotic-producing and pathogenic bacteria. This paper deals with this problem from four points of view. First, the antibiotic resistance genes in producers are discussed related to their biosynthesis. Most resistance genes are present within the biosynthetic gene clusters, but some genes such as paromomycin acetyltransferases are located far outside the gene cluster. Second, when the antibiotic resistance genes in pathogens are compared with those in the producers, resistance mechanisms have dependency on antibiotic classes, and, in addition, new types of resistance mechanisms such as Eis aminoglycoside acetyltransferase and self-sacrifice proteins in enediyne antibiotics emerge in pathogens. Third, the relationships of the resistance genes between producers and pathogens are reevaluated at their amino acid sequence as well as nucleotide sequence levels. Pathogenic bacteria possess other resistance mechanisms than those in antibiotic producers. In addition, resistance mechanisms are little different between early stage of antibiotic use and the present time, e.g., β-lactam resistance in Staphylococcus aureus. Lastly, guanine + cytosine (GC) barrier in gene transfer to pathogenic bacteria is considered. Now, the resistance genes constitute resistome composed of complicated mixture from divergent environments.
Collapse
Affiliation(s)
- Hiroshi Ogawara
- HO Bio Institute, 33-9, Yushima-2, Bunkyo-ku, Tokyo 113-0034, Japan.
- Department of Biochemistry, Meiji Pharmaceutical University, 522-1, Noshio-2, Kiyose, Tokyo 204-8588, Japan.
| |
Collapse
|
3
|
Abstract
ABSTRACT
Previously, leaderless mRNAs (lmRNAs) were perceived to make up only a minor fraction of the transcriptome in bacteria. However, advancements in RNA sequencing technology are uncovering vast numbers of lmRNAs, particularly in archaea,
Actinobacteria
, and extremophiles and thus underline their significance in cellular physiology and regulation. Due to the absence of conventional ribosome binding signals, lmRNA translation initiation is distinct from canonical mRNAs and can therefore be differentially regulated. The ribosome’s inherent ability to bind a 5′-terminal AUG can stabilize and protect the lmRNA from degradation or allow ribosomal loading for downstream initiation events. As a result, lmRNAs remain translationally competent during a variety of physiological conditions, allowing them to contribute to multiple regulatory mechanisms. Furthermore, the abundance of lmRNAs can increase during adverse conditions through the upregulation of lmRNA transcription from alternative promoters or by the generation of lmRNAs from canonical mRNAs cleaved by an endonucleolytic toxin. In these ways, lmRNA translation can continue during stress and contribute to regulation, illustrating their importance in the cell. Due to their presence in all domains of life and their ability to be translated by heterologous hosts, lmRNAs appear further to represent ancestral transcripts that might allow us to study the evolution of the ribosome and the translational process.
Collapse
|
4
|
Ogawara H. Comparison of Strategies to Overcome Drug Resistance: Learning from Various Kingdoms. Molecules 2018; 23:E1476. [PMID: 29912169 PMCID: PMC6100412 DOI: 10.3390/molecules23061476] [Citation(s) in RCA: 3] [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: 05/04/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 11/16/2022] Open
Abstract
Drug resistance, especially antibiotic resistance, is a growing threat to human health. To overcome this problem, it is significant to know precisely the mechanisms of drug resistance and/or self-resistance in various kingdoms, from bacteria through plants to animals, once more. This review compares the molecular mechanisms of the resistance against phycotoxins, toxins from marine and terrestrial animals, plants and fungi, and antibiotics. The results reveal that each kingdom possesses the characteristic features. The main mechanisms in each kingdom are transporters/efflux pumps in phycotoxins, mutation and modification of targets and sequestration in marine and terrestrial animal toxins, ABC transporters and sequestration in plant toxins, transporters in fungal toxins, and various or mixed mechanisms in antibiotics. Antibiotic producers in particular make tremendous efforts for avoiding suicide, and are more flexible and adaptable to the changes of environments. With these features in mind, potential alternative strategies to overcome these resistance problems are discussed. This paper will provide clues for solving the issues of drug resistance.
Collapse
Affiliation(s)
- Hiroshi Ogawara
- HO Bio Institute, Yushima-2, Bunkyo-ku, Tokyo 113-0034, Japan.
- Department of Biochemistry, Meiji Pharmaceutical University, Noshio-2, Kiyose, Tokyo 204-8588, Japan.
| |
Collapse
|
5
|
Tenconi E, Rigali S. Self-resistance mechanisms to DNA-damaging antitumor antibiotics in actinobacteria. Curr Opin Microbiol 2018; 45:100-108. [PMID: 29642052 DOI: 10.1016/j.mib.2018.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/08/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
Abstract
Streptomyces and few other Actinobacteria naturally produce compounds currently used in chemotherapy for being cytotoxic against various types of tumor cells by damaging the DNA structure and/or inhibiting DNA functions. DNA-damaging antitumor antibiotics belong to different classes of natural compounds that are structurally unrelated such as anthracyclines, bleomycins, enediynes, mitomycins, and prodiginines. By targeting a ubiquitous molecule and housekeeping functions, these compounds are also cytotoxic to their producer. How DNA-damaging antitumor antibiotics producing actinobacteria avoid suicide is the theme of the current review which illustrates the different strategies developed for self-resistance such as toxin sequestration, efflux, modification, destruction, target repair/protection, or stochastic activity. Finally, the observed spatio-temporal correlation between cell death, morphogenesis, and prodiginine production in S. coelicolor suggests a new physiological role for these molecules, that, together with their self-resistance mechanisms, would function as new types of toxin-antitoxin systems recruited in programmed cell death processes of the producer.
Collapse
Affiliation(s)
- Elodie Tenconi
- InBioS - Center for Protein Engineering, Université de liège, Institut de Chimie B64, B-4000 Liège, Belgium
| | - Sébastien Rigali
- InBioS - Center for Protein Engineering, Université de liège, Institut de Chimie B64, B-4000 Liège, Belgium.
| |
Collapse
|
6
|
Srivastava A, Gogoi P, Deka B, Goswami S, Kanaujia SP. In silico analysis of 5'-UTRs highlights the prevalence of Shine-Dalgarno and leaderless-dependent mechanisms of translation initiation in bacteria and archaea, respectively. J Theor Biol 2016; 402:54-61. [PMID: 27155047 DOI: 10.1016/j.jtbi.2016.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 11/26/2022]
Abstract
In prokaryotes, a heterogeneous set of protein translation initiation mechanisms such as Shine-Dalgarno (SD) sequence-dependent, SD sequence-independent or ribosomal protein S1 mediated and leaderless transcript-dependent exists. To estimate the distribution of coding sequences employing a particular translation initiation mechanism, a total of 107 prokaryotic genomes were analysed using in silico approaches. Analysis of 5'-untranslated regions (UTRs) of genes reveals the existence of three types of mRNAs described as transcripts with and without SD motif and leaderless transcripts. Our results indicate that although all the three types of translation initiation mechanisms are widespread among prokaryotes, the number of SD-dependent genes in bacteria is higher than that of archaea. In contrast, archaea contain a significantly higher number of leaderless genes than SD-led genes. The correlation analysis between genome size and SD-led & leaderless genes suggests that the SD-led genes are decreasing (increasing) with genome size in bacteria (archaea). However, the leaderless genes are increasing (decreasing) in bacteria (archaea) with genome size. Moreover, an analysis of the start-codon biasness confirms that among ATG, GTG and TTG codons, ATG is indeed the most preferred codon at the translation initiation site in most of the coding sequences. In leaderless genes, however, the codons GTG and TTG are also observed at the translation initiation site in some species contradicting earlier studies which suggested the usage of only ATG codon. Henceforth, the conventional mechanism of translation initiation cannot be generalized as an exclusive way of initiating the process of protein biosynthesis in prokaryotes.
Collapse
Affiliation(s)
- Ambuj Srivastava
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Prerana Gogoi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Bhagyashree Deka
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India
| | - Shrayanti Goswami
- Department of Biotechnology, National Institute of Technology Durgapur, Durgapur 713205, West Bengal, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| |
Collapse
|
7
|
Wang S, Liu K, Xiao L, Yang L, Li H, Zhang F, Lei L, Li S, Feng X, Li A, He J. Characterization of a novel DNA glycosylase from S. sahachiroi involved in the reduction and repair of azinomycin B induced DNA damage. Nucleic Acids Res 2015; 44:187-97. [PMID: 26400161 PMCID: PMC4705692 DOI: 10.1093/nar/gkv949] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/13/2015] [Indexed: 01/27/2023] Open
Abstract
Azinomycin B is a hybrid polyketide/nonribosomal peptide natural product and possesses antitumor activity by interacting covalently with duplex DNA and inducing interstrand crosslinks. In the biosynthetic study of azinomycin B, a gene (orf1) adjacent to the azinomycin B gene cluster was found to be essential for the survival of the producer, Streptomyces sahachiroi ATCC33158. Sequence analyses revealed that Orf1 belongs to the HTH_42 superfamily of conserved bacterial proteins which are widely distributed in pathogenic and antibiotic-producing bacteria with unknown functions. The protein exhibits a protective effect against azinomycin B when heterologously expressed in azinomycin-sensitive strains. EMSA assays showed its sequence nonspecific binding to DNA and structure-specific binding to azinomycin B-adducted sites, and ChIP assays revealed extensive association of Orf1 with chromatin in vivo. Interestingly, Orf1 not only protects target sites by protein–DNA interaction but is also capable of repairing azinomycin B-mediated DNA cross-linking. It possesses the DNA glycosylase-like activity and specifically repairs DNA damage induced by azinomycin B through removal of both adducted nitrogenous bases in the cross-link. This bifunctional protein massively binds to genomic DNA to reduce drug attack risk as a novel DNA binding protein and triggers the base excision repair system as a novel DNA glycosylase.
Collapse
Affiliation(s)
- Shan Wang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Le Xiao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - LiYuan Yang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hong Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - FeiXue Zhang
- State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Lei Lei
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - ShengQing Li
- State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Xu Feng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - AiYing Li
- State Key Laboratory of Microbial Technology, Shandong University Helmholtz Joint Institute of Biotechnology, School of Life Science, Shandong University, Jinan 250100, China
| | - Jing He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| |
Collapse
|
8
|
Bass PD, Gubler DA, Judd TC, Williams RM. Mitomycinoid alkaloids: mechanism of action, biosynthesis, total syntheses, and synthetic approaches. Chem Rev 2013; 113:6816-63. [PMID: 23654296 PMCID: PMC3864988 DOI: 10.1021/cr3001059] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Phillip D Bass
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States
| | | | | | | |
Collapse
|
9
|
Schrempf H, Koebsch I, Walter S, Engelhardt H, Meschke H. Extracellular Streptomyces vesicles: amphorae for survival and defence. Microb Biotechnol 2011; 4:286-99. [PMID: 21342473 PMCID: PMC3818868 DOI: 10.1111/j.1751-7915.2011.00251.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 01/12/2011] [Indexed: 11/27/2022] Open
Abstract
Blue-pigmented exudates arise as droplets on sporulated lawns of Streptomyces coelicolor M110 grown on agar plates. Our electron microscopical and biochemical studies suggest that droplets contain densely packed vesicles with large assemblies of different protein types and/or the polyketide antibiotic actinorhodin. Frozen-hydrated vesicles were unilamellar with a typical bilayer membrane, and ranged from 80 to 400 nm in diameter with a preferred width of 150-300 nm. By means of cryo-electron tomography, three types were reconstructed three-dimensionally: vesicles that were filled with particulate material, likely protein assemblies, those that contained membrane-bound particles, and a vesicle that showed a higher contrast inside, but lacked particles. Our LC/MS analyses of generated tryptic peptides led to the identification of distinct proteins that carry often a predicted N-terminal signal peptide with a twin-arginine motif or lack a canonical signal sequence. The proteins are required for a range of processes: the acquisition of inorganic as well as organic phosphate, iron ions, and of distinct carbon sources, energy metabolism and redox balance, defence against oxidants and tellurites, the tailoring of actinorhodin, folding and assembly of proteins, establishment of turgor, and different signalling cascades. Our novel findings have immense implications for understanding new avenues of environmental biology of streptomycetes and for biotechnological applications.
Collapse
Affiliation(s)
- Hildgund Schrempf
- FB Biology/Chemistry, Applied Genetics of Microorganisms, University Osnabrück, Barbarastr. 13, D-49069 Osnabrück, Germany.
| | | | | | | | | |
Collapse
|
10
|
Olano C, Méndez C, Salas JA. Molecular insights on the biosynthesis of antitumour compounds by actinomycetes. Microb Biotechnol 2010; 4:144-64. [PMID: 21342461 PMCID: PMC3818856 DOI: 10.1111/j.1751-7915.2010.00231.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Natural products are traditionally the main source of drug leads. In particular, many antitumour compounds are either natural products or derived from them. However, the search for novel antitumour drugs active against untreatable tumours, with fewer side-effects or with enhanced therapeutic efficiency, is a priority goal in cancer chemotherapy. Microorganisms, particularly actinomycetes, are prolific producers of bioactive compounds, including antitumour drugs, produced as secondary metabolites. Structural genes involved in the biosynthesis of such compounds are normally clustered together with resistance and regulatory genes, which facilitates the isolation of the gene cluster. The characterization of these clusters has represented, during the last 25 years, a great source of genes for the generation of novel derivatives by using combinatorial biosynthesis approaches: gene inactivation, gene expression, heterologous expression of the clusters or mutasynthesis. In addition, these techniques have been also applied to improve the production yields of natural and novel antitumour compounds. In this review we focus on some representative antitumour compounds produced by actinomycetes covering the genetic approaches used to isolate and validate their biosynthesis gene clusters, which finally led to generating novel derivatives and to improving the production yields.
Collapse
Affiliation(s)
- Carlos Olano
- Departamento de Biología Funcional and Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A), Universidad de Oviedo, 33006 Oviedo, Spain
| | | | | |
Collapse
|
11
|
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.
Collapse
Affiliation(s)
- Eric Cundliffe
- Department of Biochemistry, University of Leicester, Leicester, LE1 9HN, UK.
| | | |
Collapse
|
12
|
Olano C, Méndez C, Salas JA. Antitumor compounds from actinomycetes: from gene clusters to new derivatives by combinatorial biosynthesis. Nat Prod Rep 2009; 26:628-60. [PMID: 19387499 DOI: 10.1039/b822528a] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Covering: up to October 2008. Antitumor compounds produced by actinomycetes and novel derivatives generated by combinatorial biosynthesis are reviewed (with 318 references cited.) The different structural groups for which the relevant gene clusters have been isolated and characterized are reviewed, with a description of the strategies used for the generation of the novel derivatives and the activities of these compounds against tumor cell lines.
Collapse
Affiliation(s)
- Carlos Olano
- Departamento de Biología Funcional and Instituto Universitario de Oncología del Principado de Asturias (I.U.O.P.A.), Universidad de Oviedo, 33006, Oviedo, Spain
| | | | | |
Collapse
|
13
|
Chen HQ, Lee MH, Chung KR. Functional characterization of three genes encoding putative oxidoreductases required for cercosporin toxin biosynthesis in the fungus Cercospora nicotianae. MICROBIOLOGY-SGM 2007; 153:2781-2790. [PMID: 17660442 DOI: 10.1099/mic.0.2007/007294-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cercosporin is a non-host-selective, photoactivated polyketide toxin produced by many phytopathogenic Cercospora species, which plays a crucial role during pathogenesis on host plants. Upon illumination, cercosporin converts oxygen molecules to toxic superoxide and singlet oxygen that damage various cellular components and induce lipid peroxidation and electrolyte leakage. Three genes (CTB5, CTB6 and CTB7) encoding putative FAD/FMN- or NADPH-dependent oxidoreductases in the cercosporin toxin biosynthetic pathway of C. nicotianae were functionally analysed. Replacement of each gene via double recombination was utilized to create null mutant strains that were completely impaired in cercosporin production as a consequence of specific interruption at the CTB5, CTB6 or CTB7 locus. Expression of CTB1, CTB5, CTB6, CTB7 and CTB8 was drastically reduced or nearly abolished when CTB5, CTB6 or CTB7 was disrupted. Production of cercosporin was revived when a functional gene cassette was introduced into the respective mutants. All ctb5, ctb6 and ctb7 null mutants retained wild-type levels of resistance against toxicity of cercosporin or singlet-oxygen-generating compounds, indicating that none of the genes plays a role in self-protection.
Collapse
Affiliation(s)
- Hui-Qin Chen
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| | - Miin-Huey Lee
- Department of Plant Pathology, National Chung-Hsing University, Taichung 402, Taiwan
| | - Kuang-Ren Chung
- Department of Plant Pathology, Institute of Food and Agricultural Sciences (IFAS), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
- Citrus Research and Education Center, Institute of Food and Agricultural Sciences (IFAS), University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA
| |
Collapse
|
14
|
Cho EM, Liu L, Farmerie W, Keyhani NO. EST analysis of cDNA libraries from the entomopathogenic fungus Beauveria (Cordyceps) bassiana. I. Evidence for stage-specific gene expression in aerial conidia, in vitro blastospores and submerged conidia. MICROBIOLOGY-SGM 2006; 152:2843-2854. [PMID: 16946278 DOI: 10.1099/mic.0.28844-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The entomopathogenic fungus Beauveria (Cordyceps) bassiana holds much promise as a pest biological control agent. B. bassiana produces at least three in vitro single cell infectious propagules, including aerial conidia, vegetative cells termed blastospores and submerged conidia, that display different morphological, biochemical and virulence properties. Populations of aerial conidia, blastospores and submerged conidia were produced on agar plates, rich liquid broth cultures and under conditions of nutrient limitation in submerged cultures, respectively. cDNA libraries were generated from mRNA isolated from each B. bassiana cell type and approximately 2,500 5' end sequences were determined from each library. Sequences derived from aerial conidia clustered into 284 contigs and 963 singlets, with those derived from blastospores and submerged conidia forming 327 contigs with 788 singlets, and 303 contigs and 1,079 contigs, respectively. Almost half (40-45 %) of the sequences in each library displayed either no significant similarity (e value >10(-4)) or similarity to hypothetical proteins found in the NCBI database. The expressed sequence tag dataset also included sequences representing a significant portion of proteins in cellular metabolism, information storage and processing, transport and cell processes, including cell division and posttranslational modifications. Transcripts encoding a diverse array of pathogenicity-related genes, including proteases, lipases, esterases, phosphatases and enzymes producing toxic secondary metabolites, were also identified. Comparative analysis between the libraries identified 2,416 unique sequences, of which 20-30 % were unique to each library, and only approximately 6 % of the sequences were shared between all three libraries. The unique and divergent representation of the B. bassiana transcriptome in the cDNA libraries from each cell type suggests robust differential gene expression profiles in response to environmental conditions.
Collapse
Affiliation(s)
- Eun-Min Cho
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Li Liu
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL 32611, USA
| | - William Farmerie
- Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL 32611, USA
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| |
Collapse
|
15
|
Galm U, Hager MH, Van Lanen SG, Ju J, Thorson JS, Shen B. Antitumor Antibiotics: Bleomycin, Enediynes, and Mitomycin. Chem Rev 2005; 105:739-58. [PMID: 15700963 DOI: 10.1021/cr030117g] [Citation(s) in RCA: 418] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ute Galm
- Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53705, USA
| | | | | | | | | | | |
Collapse
|
16
|
Affiliation(s)
- Helen A Seow
- Department of Pharmacology and Developmental Therapeutics Program, Cancer Center, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | | | | | | |
Collapse
|
17
|
Martin TW, Dauter Z, Devedjiev Y, Sheffield P, Jelen F, He M, Sherman DH, Otlewski J, Derewenda ZS, Derewenda U. Molecular basis of mitomycin C resistance in streptomyces: structure and function of the MRD protein. Structure 2002; 10:933-42. [PMID: 12121648 DOI: 10.1016/s0969-2126(02)00778-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mitomycin C (MC) is a potent anticancer agent. Streptomyces lavendulae, which produces MC, protects itself from the lethal effects of the drug by expressing several resistance proteins. One of them (MRD) binds MC and functions as a drug exporter. We report the crystal structure of MRD and its complex with an MC metabolite, 1,2-cis-1-hydroxy-2,7-diaminomitosene, at 1.5 A resolution. The drug is sandwiched by pi-stacking interactions of His-38 and Trp-108. MRD is a dimer. The betaalphabetabetabeta fold of the MRD molecule is reminiscent of methylmalonyl-CoA epimerase, bleomycin resistance proteins, glyoxalase I, and extradiol dioxygenases. The location of the binding site is identical to the ones in evolutionarily related enzymes, suggesting that the protein may have been recruited from a different metabolic pathway.
Collapse
Affiliation(s)
- T W Martin
- Department of Molecular Physiology and Biological Physics, University of Virginia, Health Sciences System, Charlottesville 22908, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Moll I, Grill S, Gualerzi CO, Bläsi U. Leaderless mRNAs in bacteria: surprises in ribosomal recruitment and translational control. Mol Microbiol 2002; 43:239-46. [PMID: 11849551 DOI: 10.1046/j.1365-2958.2002.02739.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
It is commonly believed that the translational efficiency of prokaryotic mRNAs is intrinsically determined by both primary and secondary structures of their translational initiation regions. However, for leaderless mRNAs starting with the AUG initiating codon occurring in bacteria, archaea and eukaryotes, there is no evidence for ribosomal recruitment signals downstream of the 5'-terminal AUG that seems to be the only necessary and constant element. Studies in Escherichia coli have brought to light that the ratio of initiation factors IF2 and IF3 plays a decisive role in translation initiation of leaderless mRNA, indicating that the translational efficiency of this mRNA class can be modulated depending on the availability of components of the translational machinery. Recent data suggested that the start codon of bacterial leaderless mRNAs is recognized by a ribosome-IF2-fMet-tRNA complex, an intermediate equivalent to that obligatorily formed during translation initiation in eukaryotes, which points to a conceptual similarity in all initiation pathways. In fact, the faithful translation of leaderless mRNAs in heterologous systems shows that the ability to translate leaderless mRNAs is an evolutionarily conserved function of the translational apparatus.
Collapse
Affiliation(s)
- Isabella Moll
- Institute of Microbiology and Genetics, Vienna Biocenter, 1030 Vienna, Austria
| | | | | | | |
Collapse
|
19
|
Penketh PG, Hodnick WF, Belcourt MF, Shyam K, Sherman DH, Sartorelli AC. Inhibition of DNA cross-linking by mitomycin C by peroxidase-mediated oxidation of mitomycin C hydroquinone. J Biol Chem 2001; 276:34445-52. [PMID: 11457837 DOI: 10.1074/jbc.m104263200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mitomycin C requires reductive activation to cross-link DNA and express anticancer activity. Reduction of mitomycin C (40 microm) by sodium borohydride (200 microm) in 20 mm Tris-HCl, 1 mm EDTA at 37 degrees C, pH 7.4, gives a 50-60% yield of the reactive intermediate mitomycin C hydroquinone. The hydroquinone decays with first order kinetics or pseudo first order kinetics with a t(12) of approximately 15 s under these conditions. The cross-linking of T7 DNA in this system followed matching kinetics, with the conversion of mitomycin C hydroquinone to leuco-aziridinomitosene appearing to be the rate-determining step. Several peroxidases were found to oxidize mitomycin C hydroquinone to mitomycin C and to block DNA cross-linking to various degrees. Concentrations of the various peroxidases that largely blocked DNA cross-linking, regenerated 10-70% mitomycin C from the reduced material. Thus, significant quantities of products other than mitomycin C were produced by the peroxidase-mediated oxidation of mitomycin C hydroquinone or products derived therefrom. Variations in the sensitivity of cells to mitomycin C have been attributed to differing levels of activating enzymes, export pumps, and DNA repair. Mitomycin C hydroquinone-oxidizing enzymes give rise to a new mechanism by which oxic/hypoxic toxicity differentials and resistance can occur.
Collapse
Affiliation(s)
- P G Penketh
- Department of Pharmacology and Developmental Therapeutics Program, Cancer Center, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | | | | | | | | | | |
Collapse
|
20
|
Characterization of a quinone reductase activity for the mitomycin C binding protein (MRD): Functional switching from a drug-activating enzyme to a drug-binding protein. Proc Natl Acad Sci U S A 2001. [PMID: 11158572 PMCID: PMC14686 DOI: 10.1073/pnas.031314998] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Self-protection in the mitomycin C (MC)-producing microorganism Streptomyces lavendulae includes MRD, a protein that binds MC in the presence of NADH and functions as a component of a unique drug binding-export system. Characterization of MRD revealed that it reductively transforms MC into 1,2-cis-1-hydroxy-2,7-diaminomitosene, a compound that is produced in the reductive MC activation cascade. However, the reductive reaction catalyzed by native MRD is slow, and both MC and the reduced product are bound to MRD for a relatively prolonged period. Gene shuffling experiments generated a mutant protein (MRD(E55G)) that conferred a 2-fold increase in MC resistance when expressed in Escherichia coli. Purified MRD(E55G) reduces MC twice as fast as native MRD, generating three compounds that are identical to those produced in the reductive activation of MC. Detailed amino acid sequence analysis revealed that the region around E55 in MRD strongly resembles the second active site of prokaryotic catalase-peroxidases. However, native MRD has an aspartic acid (D52) and a glutamic acid (E55) residue at the positions corresponding to the catalytic histidine and a nearby glycine residue in the catalase-peroxidases. Mutational analysis demonstrated that MRD(D52H) and MRD(D52H/E55G) conferred only marginal resistance to MC in E. coli. These findings suggest that MRD has descended from a previously unidentified quinone reductase, and mutations at the active site of MRD have greatly attenuated its catalytic activity while preserving substrate-binding capability. This presumed evolutionary process might have switched MRD from a potential drug-activating enzyme into the drug-binding component of the MC export system.
Collapse
|
21
|
He M, Sheldon PJ, Sherman DH. Characterization of a quinone reductase activity for the mitomycin C binding protein (MRD): Functional switching from a drug-activating enzyme to a drug-binding protein. Proc Natl Acad Sci U S A 2001; 98:926-31. [PMID: 11158572 PMCID: PMC14686 DOI: 10.1073/pnas.98.3.926] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Self-protection in the mitomycin C (MC)-producing microorganism Streptomyces lavendulae includes MRD, a protein that binds MC in the presence of NADH and functions as a component of a unique drug binding-export system. Characterization of MRD revealed that it reductively transforms MC into 1,2-cis-1-hydroxy-2,7-diaminomitosene, a compound that is produced in the reductive MC activation cascade. However, the reductive reaction catalyzed by native MRD is slow, and both MC and the reduced product are bound to MRD for a relatively prolonged period. Gene shuffling experiments generated a mutant protein (MRD(E55G)) that conferred a 2-fold increase in MC resistance when expressed in Escherichia coli. Purified MRD(E55G) reduces MC twice as fast as native MRD, generating three compounds that are identical to those produced in the reductive activation of MC. Detailed amino acid sequence analysis revealed that the region around E55 in MRD strongly resembles the second active site of prokaryotic catalase-peroxidases. However, native MRD has an aspartic acid (D52) and a glutamic acid (E55) residue at the positions corresponding to the catalytic histidine and a nearby glycine residue in the catalase-peroxidases. Mutational analysis demonstrated that MRD(D52H) and MRD(D52H/E55G) conferred only marginal resistance to MC in E. coli. These findings suggest that MRD has descended from a previously unidentified quinone reductase, and mutations at the active site of MRD have greatly attenuated its catalytic activity while preserving substrate-binding capability. This presumed evolutionary process might have switched MRD from a potential drug-activating enzyme into the drug-binding component of the MC export system.
Collapse
Affiliation(s)
- M He
- Department of Microbiology and Biological Process Technology Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | |
Collapse
|
22
|
Abstract
The goal of this study was to identify the biosynthetic cluster for zwittermicin A, a novel, broad spectrum, aminopolyol antibiotic produced by Bacillus cereus. The nucleotide sequence of 2.7kb of DNA flanking the zwittermicin A self-resistance gene, zmaR, from B. cereus UW85 revealed three open reading frames (ORFs). Of these ORFs, two had sequence similarity to acyl-CoA dehydrogenases and polyketide synthases, respectively. Insertional inactivation demonstrated that orf2 is necessary for zwittermicin A production and that zmaR is necessary for high-level resistance to zwittermicin A but is not required for zwittermicin A production. Expression of ZmaR was temporally associated with zwittermicin A production. The results suggest that zmaR is part of a cluster of genes that is involved in zwittermicin A biosynthesis, representing the first biosynthetic pathway for an aminopolyol antibiotic.
Collapse
Affiliation(s)
- E A Stohl
- Department of Plant Pathology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA
| | | | | |
Collapse
|
23
|
Belcourt MF, Penketh PG, Hodnick WF, Johnson DA, Sherman DH, Rockwell S, Sartorelli AC. Mitomycin resistance in mammalian cells expressing the bacterial mitomycin C resistance protein MCRA. Proc Natl Acad Sci U S A 1999; 96:10489-94. [PMID: 10468636 PMCID: PMC17916 DOI: 10.1073/pnas.96.18.10489] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mitomycin C-resistance gene, mcrA, of Streptomyces lavendulae produces MCRA, a protein that protects this microorganism from its own antibiotic, the antitumor drug mitomycin C. Expression of the bacterial mcrA gene in mammalian Chinese hamster ovary cells causes profound resistance to mitomycin C and to its structurally related analog porfiromycin under aerobic conditions but produces little change in drug sensitivity under hypoxia. The mitomycins are prodrugs that are enzymatically reduced and activated intracellularly, producing cytotoxic semiquinone anion radical and hydroquinone reduction intermediates. In vitro, MCRA protects DNA from cross-linking by the hydroquinone reduction intermediate of these mitomycins by oxidizing the hydroquinone back to the parent molecule; thus, MCRA acts as a hydroquinone oxidase. These findings suggest potential therapeutic applications for MCRA in the treatment of cancer with the mitomycins and imply that intrinsic or selected mitomycin C resistance in mammalian cells may not be due solely to decreased bioactivation, as has been hypothesized previously, but instead could involve an MCRA-like mechanism.
Collapse
Affiliation(s)
- M F Belcourt
- Department of Pharmacology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Mao Y, Varoglu M, Sherman DH. Genetic localization and molecular characterization of two key genes (mitAB) required for biosynthesis of the antitumor antibiotic mitomycin C. J Bacteriol 1999; 181:2199-208. [PMID: 10094699 PMCID: PMC93634 DOI: 10.1128/jb.181.7.2199-2208.1999] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/1998] [Accepted: 01/12/1999] [Indexed: 11/20/2022] Open
Abstract
Mitomycin C (MC) is an antitumor antibiotic derived biosynthetically from 3-amino-5-hydroxybenzoic acid (AHBA), D-glucosamine, and carbamoyl phosphate. A gene (mitA) involved in synthesis of AHBA has been identified and found to be linked to the MC resistance locus, mrd, in Streptomyces lavendulae. Nucleotide sequence analysis showed that mitA encodes a 388-amino-acid protein that has 71% identity (80% similarity) with the rifamycin AHBA synthase from Amycolatopsis mediterranei, as well as with two additional AHBA synthases from related ansamycin antibiotic-producing microorganisms. Gene disruption and site-directed mutagenesis of the S. lavendulae chromosomal copy of mitA completely blocked the production of MC. The function of mitA was confirmed by complementation of an S. lavendulae strain containing a K191A mutation in MitA with AHBA. A second gene (mitB) encoding a 272-amino-acid protein (related to a group of glycosyltransferases) was identified immediately downstream of mitA that upon disruption resulted in abrogation of MC synthesis. This work has localized a cluster of key genes that mediate assembly of the unique mitosane class of natural products.
Collapse
Affiliation(s)
- Y Mao
- Department of Microbiology and Biological Process Technology Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | |
Collapse
|
25
|
Mao Y, Varoglu M, Sherman DH. Molecular characterization and analysis of the biosynthetic gene cluster for the antitumor antibiotic mitomycin C from Streptomyces lavendulae NRRL 2564. CHEMISTRY & BIOLOGY 1999; 6:251-63. [PMID: 10099135 DOI: 10.1016/s1074-5521(99)80040-4] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND The mitomycins are natural products that contain a variety of functional groups, including aminobenzoquinone- and aziridine-ring systems. Mitomycin C (MC) was the first recognized bioreductive alkylating agent, and has been widely used clinically for antitumor therapy. Precursor-feeding studies showed that MC is derived from 3-amino-5-hydroxybenzoic acid (AHBA), D-glucosamine, L-methionine and carbamoyl phosphate. A genetically linked AHBA biosynthetic gene and MC resistance genes were identified previously in the MC producer Streptomyces lavendulae NRRL 2564. We set out to identify other genes involved in MC biosynthesis. RESULTS A cluster of 47 genes spanning 55 kilobases of S. lavendulae DNA governs MC biosynthesis. Fourteen of 22 disruption mutants did not express or overexpressed MC. Seven gene products probably assemble the AHBA intermediate through a variant of the shikimate pathway. The gene encoding the first presumed enzyme in AHBA biosynthesis is not, however, linked within the MC cluster. Candidate genes for mitosane nucleus formation and functionalization were identified. A putative MC translocase was identified that comprises a novel drug-binding and export system, which confers cellular self-protection on S. lavendulae. Two regulatory genes were also identified. CONCLUSIONS The overall architecture of the MC biosynthetic gene cluster in S. lavendulae has been determined. Targeted manipulation of a putative MC pathway regulator led to a substantial increase in drug production. The cloned genes should help elucidate the molecular basis for creation of the mitosane ring system, as well efforts to engineer the biosynthesis of novel natural products.
Collapse
Affiliation(s)
- Y Mao
- University of Minnesota, Department of Microbiology, Biological ProcessTechnology Institute, 1460 Mayo Memorial Building, Box 196 UFHC, 420 Delaware Street S.E., Minneapolis, MN 55455, USA
| | | | | |
Collapse
|
26
|
Sheldon PJ, Mao Y, He M, Sherman DH. Mitomycin resistance in Streptomyces lavendulae includes a novel drug-binding-protein-dependent export system. J Bacteriol 1999; 181:2507-12. [PMID: 10198016 PMCID: PMC93678 DOI: 10.1128/jb.181.8.2507-2512.1999] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequence analysis of Streptomyces lavendulae NRRL 2564 chromosomal DNA adjacent to the mitomycin resistance locus mrd (encoding a previously described mitomycin-binding protein [P. Sheldon, D. A. Johnson, P. R. August, H.-W. Liu, and D. H. Sherman, J. Bacteriol. 179:1796-1804, 1997]) revealed a putative mitomycin C (MC) transport gene (mct) encoding a hydrophobic polypeptide that has significant amino acid sequence similarity with several actinomycete antibiotic export proteins. Disruption of mct by insertional inactivation resulted in an S. lavendulae mutant strain that was considerably more sensitive to MC. Expression of mct in Escherichia coli conferred a fivefold increase in cellular resistance to MC, led to the synthesis of a membrane-associated protein, and correlated with reduced intracellular accumulation of the drug. Coexpression of mct and mrd in E. coli resulted in a 150-fold increase in resistance, as well as reduced intracellular accumulation of MC. Taken together, these data provide evidence that MRD and Mct function as components of a novel drug export system specific to the mitomycins.
Collapse
Affiliation(s)
- P J Sheldon
- Department of Microbiology and Biological Process Technology Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | | | | | | |
Collapse
|
27
|
Furuya K, Hutchinson CR. The DrrC protein of Streptomyces peucetius, a UvrA-like protein, is a DNA-binding protein whose gene is induced by daunorubicin. FEMS Microbiol Lett 1998; 168:243-9. [PMID: 9835035 DOI: 10.1111/j.1574-6968.1998.tb13280.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
DrrC, a daunorubicin resistance protein with a strong sequence similarity to the UvrA protein involved in excision repair of DNA, is induced by daunorubicin in Streptomyces peucetius and behaves like an ATP-dependent, DNA binding protein in vitro. The refolded protein obtained from expression of the drrC gene in Escherichia coli was used to conduct gel retardation assays. DrrC bound a DNA segment containing the promoter region of a daunorubicin production gene only in the presence of ATP and daunorubicin. This result suggests that DrrC is a novel type of drug self-resistance protein with DNA binding properties like those of UvrA. Western blotting analysis with a polyclonal antiserum generated against His-tagged DrrC showed that the appearance of DrrC in S. peucetius is coincident with the onset of daunorubicin production and that the drrC gene is induced by daunorubicin. These data also showed that the DnrN and DnrI regulatory proteins are required for drrC expression. The level of DrrA, another daunorubicin resistance protein that resembles ATP-dependent bacterial antiporters, was regulated in the same way as that of DrrC.
Collapse
Affiliation(s)
- K Furuya
- School of Pharmacy, University of Wisconsin, Madison 53706, USA
| | | |
Collapse
|
28
|
Huh WK, Lee BH, Kim ST, Kim YR, Rhie GE, Baek YW, Hwang CS, Lee JS, Kang SO. D-Erythroascorbic acid is an important antioxidant molecule in Saccharomyces cerevisiae. Mol Microbiol 1998; 30:895-903. [PMID: 10094636 DOI: 10.1046/j.1365-2958.1998.01133.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
D-Arabinono-1,4-lactone oxidase catalysing the final step of D-erythroascorbic acid biosynthesis was purified from the mitochondrial fraction of Saccharomyces cerevisiae. Based on the amino acid sequence analysis of the enzyme, an unknown open reading frame (ORF), YML086C, was identified as the ALO1 gene encoding the enzyme. The ORF of ALO1 encoded a polypeptide consisting of 526 amino acids with a calculated molecular mass of 59493Da. The deduced amino acid sequence of the enzyme shared 32% and 21% identity with that of L-gulono-1,4-lactone oxidase from rat and L-galactono-1,4-lactone dehydrogenase from cauliflower, respectively, and contained a putative transmembrane segment and a covalent FAD binding site. Blot hybridization analyses showed that a single copy of the gene was present in the yeast genome and that mRNA of the ALO1 gene was 1.8kb in size. In the alo1 mutants, D-erythroascorbic acid and the activity of D-arabinono-1,4-lactone oxidase could not be detected. The intracellular concentration of D-erythroascorbic acid and the enzyme activity increased up to 6.9-fold and 7.3-fold, respectively, in the transformant cells carrying ALO1 in multicopy plasmid. The alo1 mutants showed increased sensitivity towards oxidative stress, but overexpression of ALO1 made the cells more resistant to oxidative stress.
Collapse
Affiliation(s)
- W K Huh
- Department of Microbiology, College of Natural Sciences, and Research Center for Molecular Microbiology, Seoul National University, Republic of Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Salas JA, Méndez C. Genetic manipulation of antitumor-agent biosynthesis to produce novel drugs. Trends Biotechnol 1998; 16:475-82. [PMID: 9830156 DOI: 10.1016/s0167-7799(98)01198-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Current methods of obtaining novel drugs may be complemented in the near future by the genetic engineering of antitumor-agent biosynthesis in microorganisms. Biosynthetic gene clusters from several antitumor pathways in actinomycetes are presently being characterized and expressed in order to generate novel drugs. Several novel hydroxylated and glycosylated antitumor-drug derivatives have been produced that show a relaxed substrate specificity for secondary-metabolic enzymes, which opens up the possibility of generating novel drugs by genetic manipulation.
Collapse
Affiliation(s)
- J A Salas
- Departamento de Biologia Funcional e Instituto Universitario de Biotecnologia de Asturias (IUBA-CSIC), Universidad de Oviedo, Spain.
| | | |
Collapse
|
30
|
Chou WM, Kutchan TM. Enzymatic oxidations in the biosynthesis of complex alkaloids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 1998; 15:289-300. [PMID: 9750342 DOI: 10.1046/j.1365-313x.1998.00220.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The biosynthesis of complex alkaloids in plants involves enzymes that, due to high substrate specificity, appear to have evolved solely for a role in secondary metabolism. At least one class of these enzymes, the oxidoreductases, catalyze transformations that are in some cases difficult to chemically mimick with an equivalent stereo- or regiospecificity and yield. Oxidoreductases are frequently catalyzing reactions that result in the formation of parent ring systems, thereby determining the class of alkaloid that a plant will produce. The oxidoreductases of alkaloid formation are a potential target for the biotechnological exploitation of medicinal plants in that they could be used for biomimetic syntheses of alkaloids. Analyzing the molecular genetics of alkaloid biosynthetic oxidations is requisite to eventual commercial application of these enzymes. To this end, a wealth of knowledge has been gained on the biochemistry of select monoterpenoid indole and isoquinoline biosynthetic pathways, and in recent years this has been complemented by molecular genetic analyses. As the nucleotide sequences of the oxidases of alkaloid synthesis become known, consensus sequences specific to select classes of enzymes can be identified. These consensus sequences will potentially facilitate the direct cloning of alkaloid biosynthetic genes without the need to purify the native enzyme for partial amino acid sequence determination or for antibody production prior to cDNA isolation. The current state of our knowledge of the biochemistry and molecular genetics of oxidases involved in alkaloid biosynthesis is reviewed herein.
Collapse
Affiliation(s)
- W M Chou
- Laboratorium für Molekulare Biologie, Universität München, Germany
| | | |
Collapse
|
31
|
Fraaije MW, Van Berkel WJ, Benen JA, Visser J, Mattevi A. A novel oxidoreductase family sharing a conserved FAD-binding domain. Trends Biochem Sci 1998; 23:206-7. [PMID: 9644973 DOI: 10.1016/s0968-0004(98)01210-9] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- M W Fraaije
- Dept of Biomolecular Sciences, Wageningen Agricultural University, The Netherlands
| | | | | | | | | |
Collapse
|
32
|
Mewies M, McIntire WS, Scrutton NS. Covalent attachment of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) to enzymes: the current state of affairs. Protein Sci 1998; 7:7-20. [PMID: 9514256 PMCID: PMC2143808 DOI: 10.1002/pro.5560070102] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The first identified covalent flavoprotein, a component of mammalian succinate dehydrogenase, was reported 42 years ago. Since that time, more than 20 covalent flavoenzymes have been described, each possessing one of five modes of FAD or FMN linkage to protein. Despite the early identification of covalent flavoproteins, the mechanisms of covalent bond formation and the roles of the covalent links are only recently being appreciated. The main focus of this review is, therefore, one of mechanism and function, in addition to surveying the types of linkage observed and the methods employed for their identification. Case studies are presented for a variety of covalent flavoenzymes, from which general findings are beginning to emerge.
Collapse
Affiliation(s)
- M Mewies
- Department of Biochemistry, University of Leicester, UK
| | | | | |
Collapse
|
33
|
Gallegos MT, Schleif R, Bairoch A, Hofmann K, Ramos JL. Arac/XylS family of transcriptional regulators. Microbiol Mol Biol Rev 1997; 61:393-410. [PMID: 9409145 PMCID: PMC232617 DOI: 10.1128/mmbr.61.4.393-410.1997] [Citation(s) in RCA: 362] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The ArC/XylS family of prokaryotic positive transcriptional regulators includes more than 100 proteins and polypeptides derived from open reading frames translated from DNA sequences. Members of this family are widely distributed and have been found in the gamma subgroup of the proteobacteria, low- and high-G + C-content gram-positive bacteria, and cyanobacteria. These proteins are defined by a profile that can be accessed from PROSITE PS01124. Members of the family are about 300 amino acids long and have three main regulatory functions in common: carbon metabolism, stress response, and pathogenesis. Multiple alignments of the proteins of the family define a conserved stretch of 99 amino acids usually located at the C-terminal region of the regulator and connected to a nonconserved region via a linker. The conserved stretch contains all the elements required to bind DNA target sequences and to activate transcription from cognate promoters. Secondary analysis of the conserved region suggests that it contains two potential alpha-helix-turn-alpha-helix DNA binding motifs. The first, and better-fitting motif is supported by biochemical data, whereas existing biochemical data neither support nor refute the proposal that the second region possesses this structure. The phylogenetic relationship suggests that members of the family have recruited the nonconserved domain(s) into a series of existing domains involved in DNA recognition and transcription stimulation and that this recruited domain governs the role that the regulator carries out. For some regulators, it has been demonstrated that the nonconserved region contains the dimerization domain. For the regulators involved in carbon metabolism, the effector binding determinants are also in this region. Most regulators belonging to the AraC/XylS family recognize multiple binding sites in the regulated promoters. One of the motifs usually overlaps or is adjacent to the -35 region of the cognate promoters. Footprinting assays have suggested that these regulators protect a stretch of up to 20 bp in the target promoters, and multiple alignments of binding sites for a number of regulators have shown that the proteins recognize short motifs within the protected region.
Collapse
Affiliation(s)
- M T Gallegos
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Consejo Superior de Investigaciones Científicas, Estación Experimental del Zaìdín, Granada, Spain
| | | | | | | | | |
Collapse
|
34
|
Affiliation(s)
- C. Richard Hutchinson
- School of Pharmacy and Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706
| |
Collapse
|
35
|
Dickens M, Rajgarhia V, Woo A, Priestley N. Anthracyclines. DRUGS AND THE PHARMACEUTICAL SCIENCES 1997. [DOI: 10.1201/b14856-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
36
|
Johnson DA, August PR, Shackleton C, Liu HW, Sherman DH. Microbial Resistance to Mitomycins Involves a Redox Relay Mechanism. J Am Chem Soc 1997. [DOI: 10.1021/ja963880j] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David A. Johnson
- Department of Chemistry, University of Minnesota Minneapolis, Minnesota 55455 Department of Microbiology and Biological Process Technology Institute, University of Minnesota 240 Gortner Laboratory, St. Paul, Minnesota 55108 Children's Hospital Oakland Research Institute Oakland, California 94609
| | - Paul R. August
- Department of Chemistry, University of Minnesota Minneapolis, Minnesota 55455 Department of Microbiology and Biological Process Technology Institute, University of Minnesota 240 Gortner Laboratory, St. Paul, Minnesota 55108 Children's Hospital Oakland Research Institute Oakland, California 94609
| | - Cedric Shackleton
- Department of Chemistry, University of Minnesota Minneapolis, Minnesota 55455 Department of Microbiology and Biological Process Technology Institute, University of Minnesota 240 Gortner Laboratory, St. Paul, Minnesota 55108 Children's Hospital Oakland Research Institute Oakland, California 94609
| | - Hung-wen Liu
- Department of Chemistry, University of Minnesota Minneapolis, Minnesota 55455 Department of Microbiology and Biological Process Technology Institute, University of Minnesota 240 Gortner Laboratory, St. Paul, Minnesota 55108 Children's Hospital Oakland Research Institute Oakland, California 94609
| | - David H. Sherman
- Department of Chemistry, University of Minnesota Minneapolis, Minnesota 55455 Department of Microbiology and Biological Process Technology Institute, University of Minnesota 240 Gortner Laboratory, St. Paul, Minnesota 55108 Children's Hospital Oakland Research Institute Oakland, California 94609
| |
Collapse
|
37
|
Sheldon PJ, Johnson DA, August PR, Liu HW, Sherman DH. Characterization of a mitomycin-binding drug resistance mechanism from the producing organism, Streptomyces lavendulae. J Bacteriol 1997; 179:1796-804. [PMID: 9045843 PMCID: PMC178896 DOI: 10.1128/jb.179.5.1796-1804.1997] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In an effort to characterize the diversity of mechanisms involved in cellular self-protection against the antitumor antibiotic mitomycin C (MC), DNA fragments from the producing organism (Streptomyces lavendulae) were introduced into Streptomyces lividans and transformants were selected for resistance to the drug. Subcloning of a 4.0-kb BclI fragment revealed the presence of an MC resistance determinant, mrd. Nucleotide sequence analysis identified an open reading frame consisting of 130 amino acids with a predicted molecular weight of 14,364. Transcriptional analysis revealed that mrd is expressed constitutively, with increased transcription in the presence of MC. Expression of mrd in Escherichia coli resulted in the synthesis of a soluble protein with an Mr of 14,400 that conferred high-level cellular resistance to MC and a series of structurally related natural products. Purified MRD was shown to function as a drug-binding protein that provides protection against cross-linking of DNA by preventing reductive activation of MC.
Collapse
MESH Headings
- Amino Acid Sequence
- Antibiotics, Antineoplastic/metabolism
- Antibiotics, Antineoplastic/pharmacology
- Bacterial Proteins
- Base Sequence
- Carrier Proteins/chemistry
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cloning, Molecular
- DNA, Bacterial/metabolism
- Drug Resistance, Microbial/genetics
- Escherichia coli/drug effects
- Escherichia coli/genetics
- Genes, Bacterial
- Membrane Transport Proteins
- Mitomycin/metabolism
- Mitomycin/pharmacology
- Molecular Sequence Data
- RNA, Bacterial/genetics
- RNA, Messenger/genetics
- Restriction Mapping
- Sequence Analysis, DNA
- Streptomyces/drug effects
- Streptomyces/genetics
- Streptomyces/metabolism
- Transcription, Genetic
Collapse
Affiliation(s)
- P J Sheldon
- Department of Microbiology and Biological Process Technology Institute, Gortner Laboratory, University of Minnesota, St. Paul 55108, USA
| | | | | | | | | |
Collapse
|
38
|
Facchini PJ, Penzes C, Johnson AG, Bull D. Molecular characterization of berberine bridge enzyme genes from opium poppy. PLANT PHYSIOLOGY 1996; 112:1669-77. [PMID: 8972604 PMCID: PMC158100 DOI: 10.1104/pp.112.4.1669] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
In Papaver somniferum (opium poppy) and related species, (S)-reticuline serves as a branch-point intermediate in the biosynthesis of numerous isoquinoline alkaloids. The berberine bridge enzyme (BBE) ([S]-reticuline:oxygen oxidoreductase [methylene bridge forming], EC 1.5.3.9) catalyzes the stereospecific conversion of the N-methyl moiety of (S)-reticuline into the berberine bridge carbon of (S)-scoulerine and represents the first committed step in the pathway leading to the antimicrobial alkaloid sanguinarine. Three unique genomic clones (bbe1, bbe2, and bbe3) similar to a BBE cDNA from Eschscholtzia californica (California poppy) were isolated from opium poppy. Two clones (bbe2 and bbe3) contained frame-shift mutations of which bbe2 was identified as a putative, nonexpressed pseudogene by RNA blot hybridization using a gene-specific probe and by the lack of transient expression of a chimeric gene fusion between the bbe2 5' flanking region and a beta-glucuronidase reporter gene. Similarly, bbe1 was shown to be expressed in opium poppy plants and cultured cells. Genomic DNA blot-hybridization data were consistent with a limited number of bbe homologs. RNA blot hybridization showed that bbe genes are expressed in roots and stems of mature plants and in seedlings within 3 d after germination. Rapid and transient BBE mRNA accumulation also occurred after treatment with a fungal elicitor or with methyl jasmonate. However, sanguinarine was found only in roots, seedlings, and fungal elicitor-treated cell cultures.
Collapse
Affiliation(s)
- P J Facchini
- Department of Biological Sciences, University of Calgary, Alberta, Canada.
| | | | | | | |
Collapse
|
39
|
Abstract
Tetrahydrobenzylisoquinoline alkaloids comprise a diverse class of secondary metabolites with many pharmacologically active members. The biosynthesis at the enzyme level of at-least two tetrahydrobenzylisoquinoline alkaloids, the benzophenanthridine alkaloid sanguinarine in the California poppy, Eschscholtzia californica, and the bisbenzylisoquinoline alkaloid berbamunine in barberry, Berberis stolonifera, has been elucidated in detail starting from the aromatic amino acid (aa) L-tyrosine. In an initial attempt to develop alternate systems for the production of medicinally important alkaloids, one enzyme from each pathway (BBE, a covalently flavinylated enzyme of benzophenanthridine alkaloid biosynthesis and CYP80, a phenol coupling cytochrome P-450-dependent oxidase of bisbenzylisoquinoline alkaloid biosynthesis) has been purified to homogeneity, a partial aa sequence determined, and the corresponding cDNAs isolated with aid of synthetic oligos based on the aa sequences. The recombinant enzymes were actively expressed in Spotloptera frugiperda Sf9 cells using a baculovirus vector, purified and then characterized. Insect cell culture has proven to be a powerful system for the overexpression of alkaloid biosynthetic genes.
Collapse
Affiliation(s)
- T M Kutchan
- Laboratorium für Molekulare Biologie, Universität München, Germany.
| |
Collapse
|
40
|
August PR, Rahn JA, Flickinger MC, Sherman DH. Inducible synthesis of the mitomycin C resistance gene product (MCRA) from Streptomyces lavendulae. Gene 1996; 175:261-7. [PMID: 8917108 DOI: 10.1016/0378-1119(96)00172-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The mcr locus from Streptomyces lavendulae confers high level resistance (> 100 micrograms/ml) to mitomycin C (MC) and related mitomycins when cloned into Streptomyces lividans. Production of the mcrA gene product (MCRA) was shown to be MC-inducible by identification of MCRA (M(r) of 54 kDa) using Western blot analysis and enzyme linked immunosorbent assay (ELISA). The magnitude of MCRA production was dependent on MC concentration, with primary induction starting at 0.1 microgram/ml and maximum induction at 10 micrograms/ml of the drug. Different levels of MCRA production were observed when other mitomycin metabolites were used as inducers, and the level of induction related directly to aziridine ring substitution on the individual molecules. Moreover, inducible synthesis of the mcr A gene product was unique to this structural class since production of MCRA did not occur as a general response to DNA damaging agents. The time profile of intracellular MCRA synthesis correlated with MC production in S. lavendulae, suggesting coordinated regulation of MC resistance and biosynthetic genes.
Collapse
Affiliation(s)
- P R August
- Department of Microbiology, University of Minnesota, St. Paul 55108, USA
| | | | | | | |
Collapse
|
41
|
Lomovskaya N, Hong SK, Kim SU, Fonstein L, Furuya K, Hutchinson RC. The Streptomyces peucetius drrC gene encodes a UvrA-like protein involved in daunorubicin resistance and production. J Bacteriol 1996; 178:3238-45. [PMID: 8655504 PMCID: PMC178076 DOI: 10.1128/jb.178.11.3238-3245.1996] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The drrC gene, cloned from the daunorubicin (DNR)- and doxorubicin-producing strain of Streptomyces peucetius ATCC 29050, encodes a 764-amino-acid protein with a strong sequence similarity to the Escherichia coli and Micrococcus luteus UvrA proteins involved in excision repair of DNA. Expression of drrC was correlated with the timing of DNR production in the growth medium tested and was not dependent on the presence of DNR. Since introduction of drrC into Streptomyces lividans imparted a DNR resistance phenotype, this gene is believed to be a DNR resistance gene. The drrC gene could be disrupted in the non-DNR-producing S. peucetius dnrJ mutant but not in the wild-type strain, and the resulting dnrJ drrC double mutant was significantly more sensitive to DNR in efficiency-of-plating experiments. Expression of drrC in an E. coli uvrA strain conferred significant DNR resistance to this highly DNR-sensitive mutant. However, the DrrC protein did not complement the uvrA mutation to protect the mutant from the lethal effects of UV or mitomycin even though it enhanced the UV resistance of a uvrA+ strain. We speculate that the DrrC protein mediates a novel type of DNR resistance, possibly different from the mechanism of DNR resistance governed by the S. peucetius drrAB genes, which are believed to encode a DNR antiporter.
Collapse
Affiliation(s)
- N Lomovskaya
- School of Pharmacy, University of Wisconsin, Madison, 53706, USA
| | | | | | | | | | | |
Collapse
|
42
|
Otto A, Stoltz M, Sailer HP, Brandsch R. Biogenesis of the covalently flavinylated mitochondrial enzyme dimethylglycine dehydrogenase. J Biol Chem 1996; 271:9823-9. [PMID: 8621665 DOI: 10.1074/jbc.271.16.9823] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Rat dimethylglycine dehydrogenase (Me2GlyDH) was used as model protein to study the biogenesis of a covalently flavinylated mitochondrial enzyme. Here we show that: 1) enzymatically active holoenzyme correlated with trypsin resistance of the protein; 2) folding of the reticulocyte lysate-translated protein into the trypsin-resistant, holoenzyme form was a slow process that was stimulated by the presence of the flavin cofactor and was more efficient at 15 degrees C than at 30 degrees C; 3) the mitochondrial presequence reduced the extent but did not prevent holoenzyme formation; 4) covalent attachment of FAD to the Me2GlyDH apoenzyme proceeded spontaneously and did not require a mitochondrial protein factor; 5) in vitro only the precursor, but not the mature form, of the protein was imported into isolated rat liver mitochondria; in vivo, in stably transfected HepG2 cells, both the precursor and the mature form were imported into the organelle; 6) holoenzyme formation in the cytoplasm did not prevent the translocation of the proteins into the mitochondria in vivo; and 7) lack of vitamin B2 in the tissue culture medium resulted in a reduced recovery of the precursor and the mature form of Me2GlyDH from cell mitochondria, suggesting a decreased efficiency of mitochondrial protein import.
Collapse
Affiliation(s)
- A Otto
- Biochemisches Institut, Universitat Freiburg, Germany
| | | | | | | |
Collapse
|
43
|
Affiliation(s)
- M Nishikimi
- Institute of Applied Biochemistry, Gifu, Japan
| | | |
Collapse
|
44
|
Kutchan TM, Dittrich H. Characterization and mechanism of the berberine bridge enzyme, a covalently flavinylated oxidase of benzophenanthridine alkaloid biosynthesis in plants. J Biol Chem 1995; 270:24475-81. [PMID: 7592663 DOI: 10.1074/jbc.270.41.24475] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The berberine bridge enzyme ((S)-reticuline:oxygen oxidoreductase (methylene-bridge-forming), EC 1.5.3.9) catalyzes the oxidative cyclization of the N-methyl moiety of (S)-reticuline into the berberine bridge carbon, C-8, of (S)-scoulerine. This is a reaction that has neither an equivalent in organic chemistry nor a parallel in nature. The uniqueness of this catalytic reaction prompted an in depth study that began with the isolation of the cDNA encoding the berberine bridge enzyme followed by the overexpression of this cDNA in insect cell culture. The heterologously expressed enzyme has herein been shown to contain covalently attached FAD in a molar ratio of cofactor to protein of 1:1.03. Site-directed mutagenesis and laser desorption time-of-flight mass spectrometry suggest that the site of covalent attachment is at His-104. The holoenzyme exhibited absorbance maxima at 380 and 442 nm and a fluorescence emission maximum at 628 nm (310 nm excitation). Enzymic transformation of a series of (S)-reticuline derivatives modified with respect to the stereochemistry at C-1 or in the aromatic ring substitution suggests that ring closure proceeds in two steps: formation of the methylene iminium ion and subsequent ring closure via an ionic mechanism.
Collapse
Affiliation(s)
- T M Kutchan
- Laboratorium für Molekulare Biologie, Universität München, Germany
| | | |
Collapse
|
45
|
Mushegian AR, Koonin EV. A putative FAD-binding domain in a distinct group of oxidases including a protein involved in plant development. Protein Sci 1995; 4:1243-4. [PMID: 7549889 PMCID: PMC2143151 DOI: 10.1002/pro.5560040623] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Using methods for database screening with individual protein sequences and alignment blocks, a conserved domain is delineated in a group of proteins including several FAD-dependent oxidases. Two motifs within this domain resemble phosphate-binding loops and may be directly involved in FAD binding. These motifs can be readily distinguished from previously described nucleotide-binding sites using a method for database screening with position-dependent weight matrices derived from alignment blocks. Unexpectedly, this group of known and predicted FAD-dependent oxidases includes the product of the DIMINUTO gene, which is involved in Arabidopsis development, and its homologues from man and Mycobacterium leprae.
Collapse
Affiliation(s)
- A R Mushegian
- Department of Microbiology, University of Washington, Seattle 98195, USA
| | | |
Collapse
|
46
|
Stoltz M, Rysavy P, Kalousek F, Brandsch R. Folding, flavinylation, and mitochondrial import of 6-hydroxy-D-nicotine oxidase fused to the presequence of rat dimethylglycine dehydrogenase. J Biol Chem 1995; 270:8016-22. [PMID: 7713902 DOI: 10.1074/jbc.270.14.8016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We analyzed the folding, covalent flavinylation, and mitochondrial import of the rabbit reticulocyte lysate-translated bacterial 6-hydroxy-D-nicotine oxidase (6-HDNO) fused to the mitochondrial targeting sequence of rat liver dimethylglycine dehydrogenase. Translation of 6-HDNO in FAD-supplemented reticulocyte lysate resulted in a protein that contained covalently incorporated FAD, exhibited enzyme activity, and was trypsin-resistant, a characteristic of the tight conformation of the holoenzyme. The attached mitochondrial presequence did not prevent folding, binding of FAD, or enzyme activity of the 6-HDNO moiety of the fusion protein (pre-6-HDNO). Pre-6-HDNO was imported into rat liver mitochondria and processed by the mitochondrial processing peptidase. Incubation of the trypsin-resistant pre-holo-6-HDNO protein with deenergized rat liver mitochondria demonstrated that upon contact with mitochondria, the protein was unfolded and became trypsin sensitive. Mitochondrial import assays showed that the unfolded pre-holo-6-HDNO with covalently attached FAD was imported into rat liver mitochondria. Inside the mitochondrion the holo-6-HDNO was refolded into the trypsin-resistant conformation. However, when pre-apo-6-HDNO was imported only part of the protein became trypsin resistant (approximately 20%). Addition of FAD and the allosteric effector glycerol 3-phosphate to apo-6-HDNO containing mitochondrial matrix was required to transform the protein into the trypsin-resistant conformation characteristic of holo-6-HDNO.
Collapse
Affiliation(s)
- M Stoltz
- Biochemisches Institut, Universität Freiburg, Federal Republic of Germany
| | | | | | | |
Collapse
|
47
|
Liu Y, Chatterjee A, Chatterjee AK. Nucleotide sequence, organization and expression of rdgA and rdgB genes that regulate pectin lyase production in the plant pathogenic bacterium Erwinia carotovora subsp. carotovora in response to DNA-damaging agents. Mol Microbiol 1994; 14:999-1010. [PMID: 7715460 DOI: 10.1111/j.1365-2958.1994.tb01334.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In most soft-rotting Erwinia spp., including E. carotovora subsp. carotovora strain 71 (Ecc71), production of the plant cell wall degrading enzyme pectin lyase (Pnl) is activated by DNA-damaging agents such as mitomycin C (MC). Induction of Pnl production in Ecc71 requires a functional recA gene and the rdg locus. DNA sequencing and RNA analyses revealed that the rdg locus contains two regulatory genes, rdgA and rdgB, in separate transcriptional units. There is high homology between RdgA and repressors of lambdoid phages, specially phi 80. RdgB, however, has significant homology with transcriptional activators of Mu phage. Both RdgA and RdgB are also predicted to possess helix-turn-helix motifs. By replacing the rdgB promoter with the IPTG-inducible tac promoter, we have determined that rdgB by itself can activate Pnl production in Escherichia coli. However, deletion analysis of rdg+ DNA indicated that, when driven by their native promoters, functions of both rdgA and rdgB are required for the induction of pnlA expression by MC treatment. While rdgB transcription occurs only after MC treatment, a substantial level of rdgA mRNA is detected in the absence of MC treatment. Moreover, upon induction with MC, a new rdgA mRNA species, initiated from a different start site, is produced at a high level. Thus, the two closely linked rdgA and rdgB genes, required for the regulation of Pnl production, are expressed differently in Ecc71.
Collapse
Affiliation(s)
- Y Liu
- Department of Plant Pathology, University of Missouri, Columbia 65211
| | | | | |
Collapse
|