501
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Welz R, Schmidt C, Müller S. Spermine supports catalysis of hairpin ribozyme variants to differing extents. Biochem Biophys Res Commun 2001; 283:648-54. [PMID: 11341774 DOI: 10.1006/bbrc.2001.4829] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Because of the ability to cleave RNA substrates in trans, the hairpin ribozyme has great potential for therapeutic application. Activity of a three-stranded version of the minimal truncated form is enhanced by the presence of the polyamine spermine. Since spermine is the most abundant polyamine in eucariots, improved prospects for the hairpin ribozyme as therapeutic agent were predicted. We have found that not all hairpin ribozyme variants accept spermine equally well as counter-ion. Particularly the two-stranded versions commonly used for therapeutic studies show rather decreased activity when spermine is present. We have investigated a number of hairpin ribozyme derivatives regarding their ability to carry out spermine supported catalysis. Among the studied structures a two-stranded reverse-joined hairpin ribozyme displayed the highest cleavage rates in a synergistic mixture of magnesium ions and spermine. The specific features of this ribozyme along with its potential for in vivo application are discussed.
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502
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Müller S, Neureiter D, Stolte M, Verbeke C, Heuschmann P, Kirchner T, Aigner T. Tenascin: a sensitive and specific diagnostic marker of minimal collagenous colitis. Virchows Arch 2001; 438:435-41. [PMID: 11407470 DOI: 10.1007/s004280000375] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Collagenous colitis is a rare cause of chronic watery diarrhea. In this condition, endoscopic findings are usually normal. Currently, the diagnosis relies on the histological presence of thick subepithelial bands of collagen deposits and an inflammatory infiltrate within the mucosa. However, these subepithelial bands may be developed only focally and may be too subtle to allow a definitive diagnosis upon routine hematoxylin and eosin (HE) and van Gieson's stainings. Recently, we and others were able to show a prominent staining of tenascin and type-VI collagen in the subepithelial band-like structures. In this study, we tested the diagnostic value of tenascin staining and type-VI collagen immunolocalization for the identification of collagenous colitis and compared it with conventional histology and histochemical detection of collagens. The analysis was based on 434 biopsy specimens of collagenous colitis, other forms of colitis, and normal mucosa. We were able to show that the immunohistochemical detection of increased amounts of tenascin, selectively in the subepithelial zone, is a specific test for collagenous colitis, with a sensitivity superior to conventional histological and histochemical detection, especially in minimal collagenous colitis (P<0.001). Of note, tenascin staining also allows the diagnosis of collagenous colitis in biopsies obtained only from the rectum and sigmoid colon, thus avoiding the need for colonoscopic investigations. Tenascin immunostaining is a simple and safe tool to complement conventional histological diagnostics in clinically and histopathologically unclear cases of diarrhea.
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503
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Abstract
All parasitic protozoa contain polyamines and in recent years they, and their associated enzymes, have attracted attention as drug targets because they might reveal novel antiparasite therapies. How justified is this approach to drug discovery? In this review, Sylke Müller, Graham Coombs and Rolf Walter summarize the current status of research into drugs that exploit polyamine metabolism of trypanosomatid and malaria parasites, and propose priorities for research into such drugs. This review was inspired by an Expert Meeting entitled 'Polyamine Metabolism of Parasitic Protozoa as a Drug Target'.
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504
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Krnajski Z, Walter RD, Müller S. Isolation and functional analysis of two thioredoxin peroxidases (peroxiredoxins) from Plasmodium falciparum. Mol Biochem Parasitol 2001; 113:303-8. [PMID: 11295184 DOI: 10.1016/s0166-6851(01)00219-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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505
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Kunkel P, Müller S, Schirmacher P, Stavrou D, Fillbrandt R, Westphal M, Lamszus K. Expression and localization of scatter factor/hepatocyte growth factor in human astrocytomas. Neuro Oncol 2001; 3:82-8. [PMID: 11296484 PMCID: PMC1920608 DOI: 10.1093/neuonc/3.2.82] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Scatter factor/hepatocyte growth factor (SF/HGF) is a pleiotropic cytokine that has been implicated in glioma invasion and angiogenesis. The SF/HGF receptor, MET, has been found to be expressed in neoplastic astrocytes as well as in endothelial cells of the tumor vasculature. Both SF/HGF and MET expression have also been described to correlate with the malignancy grade of human gliomas. However, most glioblastoma cell lines lack SF/HGF expression, raising the question of the cellular origin of SF/HGF in vivo. Using in situ hybridization, we analyzed glioblastomas, anaplastic astrocytomas, diffuse astrocytomas, pilocytic astrocytomas, and normal brain for the expression of SF/HGF mRNA. We detected strong SF/HGF expression by the majority of the tumor cells and by vascular endothelial cells in all glioblastoma specimens analyzed. Combined use of in situ hybridization with fluorescence immunohistochemistry confirmed the astrocytic origin of the SF/HGF-expressiong cells. In contrast, CD68-immunoreactive microglia/macrophages, as well as vascular smooth muscle cells reactive to alpha-smooth muscle actin, lacked SF/HGF expression. In anaplastic, diffuse, and pilocytic astrocytomas, SF/HGF expression was confined to a subset of tumor cells, and signals were less intense than in glioblastomas. In addition, we detected SF/HGF mRNA in cortical neurons. SF/HGF expression was not up regulated around necroses or at tumor margins. MET immunoreactivity was observed in GFAP-expressing astrocytic tumor cells and endothelial cells as well as in a subset of microglia/macrophages. We conclude that in vivo, both autocrine and paracrine stimulation of tumor cells and endothelium through the SF/HGF-MET system are likely to contribute to tumor invasion and angiogenesis. Lack of SF/HGF expression by most cultured glioblastoma cells is not representative of the in vivo situation and most likely represents a culture artifact.
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506
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Degryse B, Bonaldi T, Scaffidi P, Müller S, Resnati M, Sanvito F, Arrigoni G, Bianchi ME. The high mobility group (HMG) boxes of the nuclear protein HMG1 induce chemotaxis and cytoskeleton reorganization in rat smooth muscle cells. J Cell Biol 2001; 152:1197-206. [PMID: 11257120 PMCID: PMC2199202 DOI: 10.1083/jcb.152.6.1197] [Citation(s) in RCA: 374] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
HMG1 (high mobility group 1) is a ubiquitous and abundant chromatin component. However, HMG1 can be secreted by activated macrophages and monocytes, and can act as a mediator of inflammation and endotoxic lethality. Here we document a role of extracellular HMG1 in cell migration. HMG1 (and its individual DNA-binding domains) stimulated migration of rat smooth muscle cells in chemotaxis, chemokinesis, and wound healing assays. HMG1 induced rapid and transient changes of cell shape, and actin cytoskeleton reorganization leading to an elongated polarized morphology typical of motile cells. These effects were inhibited by antibodies directed against the receptor of advanced glycation endproducts, indicating that the receptor of advanced glycation endproducts is the receptor mediating the HMG1-dependent migratory responses. Pertussis toxin and the mitogen-activated protein kinase kinase inhibitor PD98059 also blocked HMG1-induced rat smooth muscle cell migration, suggesting that a G(i/o) protein and mitogen-activated protein kinases are required for the HMG1 signaling pathway. We also show that HMG1 can be released by damage or necrosis of a variety of cell types, including endothelial cells. Thus, HMG1 has all the hallmarks of a molecule that can promote atherosclerosis and restenosis after vascular damage.
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MESH Headings
- Animals
- Cell Size/physiology
- Cells, Cultured
- Chemotactic Factors/genetics
- Chemotactic Factors/metabolism
- Chemotactic Factors/pharmacology
- Chemotaxis/drug effects
- Chemotaxis/physiology
- Culture Media, Serum-Free
- Cytoskeleton/drug effects
- Cytoskeleton/metabolism
- Endothelium, Vascular/chemistry
- Endothelium, Vascular/cytology
- Endothelium, Vascular/ultrastructure
- Enzyme Inhibitors/pharmacology
- Flavonoids/pharmacology
- Glycation End Products, Advanced/metabolism
- High Mobility Group Proteins/genetics
- High Mobility Group Proteins/metabolism
- Humans
- Microscopy, Fluorescence
- Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/ultrastructure
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Pertussis Toxin
- Protein Binding
- Rats
- Receptor for Advanced Glycation End Products
- Receptors, Immunologic/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Recombinant Proteins/pharmacology
- Signal Transduction/physiology
- Virulence Factors, Bordetella/pharmacology
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507
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Abstract
CASE REPORTS Three cases of an outbreak of familial foodborne botulism are reported. The food incriminated could not be identified despite a careful investigation into the food history of the patients. The outcome was good following endotracheal ventilation and botulism antitoxin trivalent therapy. CONCLUSION In France, foodborne botulism is an uncommon public health disease, and with a good prognosis when the diagnosis is promptly performed. The value of emergency electromyographic findings is emphasized, particularly when the repetitive stimulation of the motor nerve shows a presynaptic block of neuromuscular transmission. Management depends on the symptomatology, and trivalent antitoxin therapy is the only specific treatment.
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508
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Abstract
Covalent modification of cellular proteins by the ubiquitin-like modifier SUMO regulates various cellular processes, such as nuclear transport, signal transduction, stress response and cell-cycle progression. But, in contrast to ubiquitylation, sumoylation does not tag proteins for degradation, but seems to enhance their stability or modulate their subcellular compartmentalization.
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509
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Wernig A, Nanassy A, Müller S. Laufband (LB) therapy in spinal cord lesioned persons. PROGRESS IN BRAIN RESEARCH 2001; 128:89-97. [PMID: 11105671 DOI: 10.1016/s0079-6123(00)28009-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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510
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Veljkovic V, Metlas R, Köhler H, Urnovitz HB, Prljic J, Veljkovic N, Johnson E, Müller S. AIDS epidemic at the beginning of the third millennium: time for a new AIDS vaccine strategy. Vaccine 2001; 19:1855-62. [PMID: 11228354 DOI: 10.1016/s0264-410x(00)00194-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Current expansion of AIDS pandemic significantly accelerates AIDS vaccine research resulting in development and clinical testing of several AIDS vaccine candidates. At the same time, available experimental and clinical data demonstrate that current AIDS vaccine strategy is unsuccessful resulting in development of inefficient and harmful vaccines. This overview briefly summarizes reported results which point out the requirement for moratorium on the current clinical trials of HIV-1 gp120/160 vaccines and urgent need for development of a new, efficient and safe AIDS vaccine strategy.
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511
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Wittig B, Märten A, Dorbic T, Weineck S, Min H, Niemitz S, Trojaneck B, Flieger D, Kruopis S, Albers A, Löffel J, Neubauer A, Albers P, Müller S, Sauerbruch T, Bieber T, Huhn D, Schmidt-Wolf IG. Therapeutic vaccination against metastatic carcinoma by expression-modulated and immunomodified autologous tumor cells: a first clinical phase I/II trial. Hum Gene Ther 2001; 12:267-78. [PMID: 11177563 DOI: 10.1089/10430340150218404] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Therapeutic vaccination of tumor patients with cytokine gene-transfected tumor cells leads to tumor regression in animal models but has so far not resulted in significant clinical benefit. We and others demonstrated that tumor cells transfected to mediate overexpression of a cytokine gene activate immunologic effector cells for an improved proliferation rate and significantly higher antitumoral cytotoxic activity. Here, we performed a pilot study of therapeutic vaccination in patients with metastatic disease. Autologous tumor cells were simultaneously transfected with novel minimalistic, immunogenically defined, gene expression constructs (MIDGE) for overexpression of the two cytokines interleukin 7 (IL-7) and GM-CSF and newly designed double stem-loop immunomodulating oligodeoxyribonucleotides (d-SLIM) as a Th1-promoting and NK cell-stimulating adjuvant. Transfection was performed ex vivo by ballistomagnetic gene transfer. Patients received four subcutaneous injections of at least 1 x 10(6) of their expression-modulated and immunomodified autologous tumor cells. Ten patients have been enrolled in the study protocol. In all patients no adverse effects could be detected. IL-7 and interferon gamma levels were elevated in the serum of the patients after treatment. Interestingly, cytotoxicity of patient-derived PBLs increased significantly during treatment. All 10 patients had progressive disease when entering our protocol. One complete, one partial, and one mixed response with progression of abdominal metastases and regression of lung metastases were observed. Two patients showed a stable disease after treatment and five patients remained in progressive disease. Our observations confirm the capability of autologous expression-modified and immunomodulated tumor cell vaccines to stimulate a strong immune response in patients with metastatic cancer even in the presence of a large tumor burden.
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512
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Krnajski Z, Gilberger TW, Walter RD, Müller S. The malaria parasite Plasmodium falciparum possesses a functional thioredoxin system. Mol Biochem Parasitol 2001; 112:219-28. [PMID: 11223129 DOI: 10.1016/s0166-6851(00)00372-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The thioredoxin system consists of the NADPH dependent disulphide oxidoreductase thioredoxin reductase (TrxR) which catalyses the reduction of the small protein thioredoxin. This system is involved in a variety of biological reactions including the reduction of deoxyribonucleotides, transcription factors and hydrogen peroxide. In recent years the TrxR of the malaria parasite Plasmodium falciparum was isolated and characterised using model substrates like 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) and Escherichia coli thioredoxin. Here we report on the isolation of a cDNA encoding for P. falciparum thioredoxin (PfTrx) and the expression and characterisation of the recombinant protein, the natural substrate of PfTrxR. The deduced amino acid sequence of PfTrx encodes for a polypeptide of 11715 Da and possesses the typical thioredoxin active site motif CysGlyProCys. Both cysteine residues are essential for catalytic activity of the protein, as shown by mutational analyses. Steady state kinetic analyses with PfTrxR and PfTrx in several coupled assay systems resulted in K(m)-values for PfTrx in the range of 0.8--2.1 microM which is about 250-fold lower than for the model substrate E. coli thioredoxin. Since the turnover of both substrates is similar, the catalytic efficiency of PfTrxR to reduce the isolated PfTrx is at least 250-fold higher than to reduce E. coli thioredoxin. PfTrx contains a cysteine residue in position 43 in addition to the active-site cysteine residues, which is partially responsible for dimer formation of the protein as demonstrated by changing this amino acid into an alanine residue. Using DTNB we showed that all three cysteine residues present in PfTrx are accessible to modification by this compound. Surprisingly the first cysteine residue of the active site motif (Cys30) is less accessible than the second cysteine (Cys33), which is highly prone to the modification. These results suggest a difference in the structure and reaction mechanism of PfTrx compared to other known thioredoxins.
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513
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Raquet X, Eckert JH, Müller S, Johnsson N. Detection of altered protein conformations in living cells. J Mol Biol 2001; 305:927-38. [PMID: 11162103 DOI: 10.1006/jmbi.2000.4239] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The maturation, conformational stability, and the rate of in vivo degradation are specific for each protein and depend on both the intrinsic features of the protein and those of the surrounding cellular environment. While synthesis and degradation can be measured in living cells, stability and maturation of proteins are more difficult to quantify. We developed the split-ubiquitin method into a tool for detecting and analyzing changes in protein conformation. The biophysical parameter that forms the basis of these measurements is the time-averaged distance between the N terminus and C terminus of a protein. Starting from three proteins of known structure, we demonstrate the feasibility of this approach, and employ it to elucidate the effect of a previously described mutation in the protein Sec62p on its conformation in living cells.
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514
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Lehembre F, Müller S, Pandolfi PP, Dejean A. Regulation of Pax3 transcriptional activity by SUMO-1-modified PML. Oncogene 2001; 20:1-9. [PMID: 11244500 DOI: 10.1038/sj.onc.1204063] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2000] [Revised: 10/25/2000] [Accepted: 10/30/2000] [Indexed: 11/08/2022]
Abstract
Pax3 is an evolutionarily conserved transcription factor that plays a major role in a variety of developmental processes. Mutations in Pax3 lead to severe malformations as seen in human Waardenburg syndrome and in the Splotch mutant mice. The transcriptional activity of Pax3 was recently shown to be repressed by Daxx whereas the oncogenic fusion protein Pax3-FKHR is unresponsive to this repressive action. Here we demonstrate that Daxx-mediated repression of Pax3 can be inhibited by the nuclear body (NB)-associated protein PML. Interestingly, this suppression of Daxx properties correlates with its recruitment to the NBs. Factors such as arsenicals and interferons that enhance NB formation, trigger both the targeting of Daxx to these nuclear structures and the relief of the repressive activity of Daxx. Conversely, lack of structurally intact NBs profoundly impairs Pax3 transcriptional activity, likely by increasing the pool of available nucleoplasmic Daxx. Moreover, a PML mutant that can not be modified by the ubiquitin-related SUMO-1 modifier is no more able to interact with Daxx. Consistently, such a mutant fails both to inhibit the Daxx repressing effect on Pax3 and to induce its accumulation into the NBs. Taken together, these results argue that SUMO-1 modified PML can derepress Pax3 transcriptional activity through sequestration of the Daxx repressor into the NBs and suggest a role for these nuclear structures in the transcriptional control by Pax proteins. Oncogene (2001) 20, 1 - 9.
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515
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Müller S, Gilberger TW, Krnajski Z, Lüersen K, Meierjohann S, Walter RD. Thioredoxin and glutathione system of malaria parasite Plasmodium falciparum. PROTOPLASMA 2001; 217:43-49. [PMID: 11732337 DOI: 10.1007/bf01289412] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plasmodium falciparum is the causative agent of malaria tropica. Due to the increasing resistance towards the commonly used plasmodicidal drugs there is an urgent need to identify and assess new targets for the chemotherapeutic intervention of parasite development in the human host. It is established that P. falciparum-infected erythrocytes are vulnerable to oxidative stress, and therefore efficient antioxidative systems are required to ensure parasite development within the host cell. The thioredoxin and glutathione redox systems represent two powerful means to detoxify reactive oxygen species and this article summarizes some of the recent work which has led to a better understanding of these systems in the parasite and will help to assess them as potential targets for the development of new chemotherapeutics of malaria.
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516
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Drillet JF, Holzer F, Kallis T, Müller S, Schmidt VM. Influence of CO2 on the stability of bifunctional oxygen electrodes for rechargeable zinc/air batteries and study of different CO2 filter materials. Phys Chem Chem Phys 2001. [DOI: 10.1039/b005523i] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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517
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Müller S, Kloppe A, Weckmüller J, Prenger-Berninghoff A, Hexamer M, Mügge A, Werner J. VERGLEICH TRANSKORONARER ZU KONVENTIONELLER DEFIBRILLATIONS THERAPIE BEZÜGLICH DER FELDVERTEILUNG IM HERZEN. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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518
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Kloppe A, Prenger-Berninghoff A, Müller S, Hexamer M, Weckmüller J, Mügge A, Werner J. EIN FASEROPTISCHER SENSOR ZUR MESSUNG DER HERZKONTRAKTION. EINFLUß DER VORLASTÄNDERUNG AUF DAS MESSSIGNAL. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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519
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Prenger-Berninghoff A, Kloppe A, Müller S, Hexamer M, Werner J, Schütt U, Knobl H, Körfer R. DER EINSATZ EINER KONTINUIERLICH GEREGELTEN PERFUSION ZUM ORGANERHALT: EIN MOBILES OXYGENATIONSSYSTEM FÜR HERZEN. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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520
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Lüersen K, Müller S, Hussein A, Liebau E, Walter RD. The gamma-glutamylcysteine synthetase of Onchocerca volvulus. Mol Biochem Parasitol 2000; 111:243-51. [PMID: 11163433 DOI: 10.1016/s0166-6851(00)00325-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The tripeptide glutathione (GSH) plays an important role in the maintenance of the intracellular thiol redox state and in detoxification processes. The intracellular GSH level depends on glutathione reductase as well as on GSH synthesis. The first and rate limiting step in the synthetic pathway is catalysed by gamma-glutamylcysteine synthetase (gamma-GCS). The gamma-GCS was partially purified from the filarial parasite Onchocerca volvoulus and preliminary steady state kinetics were performed. The Ki-value for L-buthionine-S,R-sulphoximine (BSO), a specific inhibitor of gamma-GCS, was determined to be 0.13 microM, which is 54-fold lower than the Ki-value for the mammalian enzyme. Filarial gamma-GCS was also inhibited by cystamine with a Ki-value of 3.9 microM compared with 22.2 microM determined for the rat enzyme. Further, the cDNA and the gene of the O. volvulus gamma-GCS were cloned and sequenced. The gene of 5762 bp is composed of 14 exons and 13 introns. Southern blot analysis indicates that the gamma-GCS gene is present as a single-copy gene. In accordance with Northern blot analysis, the entire cDNA sequence encompasses 2377 bp. At its 5' end a nematode-specific spliced leader 130 bp upstream of the first in frame methionine was identified. The cDNA encodes a polypeptide of 652 amino acids with 50 and 69% sequence identity to the human and the Caenorhabditis elegans counterparts, respectively. The filarial gamma-GCS is proposed as a potential drug target.
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521
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Krause T, Lüersen K, Wrenger C, Gilberger TW, Müller S, Walter RD. The ornithine decarboxylase domain of the bifunctional ornithine decarboxylase/S-adenosylmethionine decarboxylase of Plasmodium falciparum: recombinant expression and catalytic properties of two different constructs. Biochem J 2000; 352 Pt 2:287-92. [PMID: 11085920 PMCID: PMC1221458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The polyamines putrescine, spermidine and spermine play an essential role in cell differentiation and proliferation. Inhibition of the rate-limiting enzymes of polyamine biosynthesis, ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC), has been proposed as a therapeutic strategy against cancer and parasitic infections. In the case of Plasmodium falciparum, the causative agent of malaria tropica, this approach is especially interesting, because here both key enzymes, ODC and AdoMetDC, are combined in a bifunctional protein, ODC/AdoMetDC. This arrangement has not been found in any other organism investigated so far. We report the cloning and recombinant expression of the ODC domain of P. falciparum in Escherichia coli. First, we expressed the mere recombinant ODC domain (rPfODC). Secondly, we expressed the recombinant ODC domain in conjunction with the preceding part of the hinge region of the bifunctional ODC/AdoMetDC (rPfHinge-ODC). K(m) values for L-ornithine were 47.3 microM for the rPfHinge-ODC and 161. 5 microM for the rPfODC. Both recombinant enzymes were inhibited by putrescine, but the K(i) value for the rPfHinge-ODC was 50.4 microM (IC(50)=157 microM), whereas the IC(50) for the rPfODC was 500 microM. Spermidine was a weak inhibitor in both cases. alpha-Difluoromethylornithine inhibited the rPfHinge-ODC with a K(i) value of 87.6 microM. For two novel ODC inhibitors, CGP52622A and CGP54619A, the K(i) values of the rPfHinge-ODC were in the nanomolar range.
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522
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Jansen R, Knopp M, Amberg W, Bernard H, Koser S, Müller S, Münster I, Pfeiffer T, Riechers H. Structural Similarity and Its Surprises: Endothelin Receptor Antagonists - Process Research and Development Report. Org Process Res Dev 2000. [DOI: 10.1021/op000040n] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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523
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Babkina OV, Evstaf'eva AG, Chichkova NV, Bartapetian AB, Müller S, Baskunov VB, Piatrauskene OV, Kochetoko SN, Gromova ES. [Recombinant components of the EcoRII restriction-modification system. Ability of restriction endonucleases to interact with DNA-RNA duplexes]. Mol Biol (Mosk) 2000; 34:1065-73. [PMID: 11186006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
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524
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Reimann J, Arbogast E, Behnke M, Müller S, Thomauske K. Thermomechanical behaviour of ceramic breeder and beryllium pebble beds. FUSION ENGINEERING AND DESIGN 2000. [DOI: 10.1016/s0920-3796(00)00357-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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525
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Welz R, Schmidt C, Müller S. [Modeling and synthesis of ribozymes]. Mol Biol (Mosk) 2000; 34:1090-6. [PMID: 11186009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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