共查询到20条相似文献,搜索用时 15 毫秒
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We designed a new approach for selection of translation enhancer sequences that enables efficient protein synthesis in cell-free systems. The selection is based on a gel shift assay of a messenger RNA (mRNA)–protein fusion product that is synthesized in a cell-free translation system using an mRNA display method. A library of randomized 20-nt-long sequences, with all possible combinations of the four nucleotides, upstream of a coding region was screened by successive rounds of screening in which the translation time of the succeeding round was reduced compared with the previous round. An efficient translation enhancer sequence capable of more rapid initiation of cell-free protein synthesis, with a minimal translation time of 5 min, than a natural longer enhancer sequence (Xenopus β-globin 5′UTR) was selected using rabbit reticulocyte extract as a model cell-free translation system. Furthermore, a successful screening of cap-independent translation enhancer sequence and a significant sequence similarity of the selected candidates validated the efficiency of the combined mRNA display and gel shift assay method for the rapid development of advanced cell-free translation systems. 相似文献
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Synthesis and maturation of green fluorescent protein in a cell-free translation system 总被引:2,自引:0,他引:2
Vyacheslav A. Kolb Eugeny V. Makeyev William W. Ward Alexander S. Spirin 《Biotechnology letters》1996,18(12):1447-1452
Summary A cell-free translation system producing mature green fluorescent protein (GFP) can be a useful tool for studying the mechanism and kinetics of GFP chromophore formation, as well as for fast protein engineering. We report here that the mature GFP can be formed in the cell-free translation system from E.coli. The synthesis of GFP in the cell-free system reaches a plateau in 30 to 40 min whereas its maturation is completed in 4 h from the beginning of translation. The delay between the GFP synthesis and the chromophore formation in the cell-free system provides the possibility to isolate and to analyse maturation intermediates for elucidation of the modification pathway. 相似文献
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Higher order structures of the 5'-proximal region decrease the efficiency of translation of the porcine pro-opiomelanocortin mRNA 总被引:4,自引:0,他引:4
D Chevrier C Vézina J Bastille C Linard N Sonenberg G Boileau 《The Journal of biological chemistry》1988,263(2):902-910
The SP6 polymerase/promoter system was used to synthesize porcine pro-opiomelanocortin mRNAs with nucleotide sequence deletions in the 5'- as well as 3'-untranslated and coding regions. The translational efficiency of the mutant mRNAs was evaluated by cell-free translation or by monitoring the rate and extent of ribosome binding in the presence of sparsomycin. The results of these experiments indicate that specific nucleotide sequences in the 5'-untranslated and coding regions of the pro-opiomelanocortin mRNA decrease its rate of translation. Structure mapping of the mRNA with double-strand and single-strand specific nucleases suggests that these sequences can form stable secondary structures. 相似文献
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Kanno T Kitano M Kato R Omori A Endo Y Tozawa Y 《Protein expression and purification》2007,52(1):59-65
Recent improvements in wheat-embryo cell-free translation resulted in a highly productive system for protein preparation. To clarify N-terminal processing of the cell-free system in a preparative-scale (> mg protein product per ml), 20 mutant variants of maltose-binding protein (MalE), each having a different penultimate residue in the sequence Met-Xaa-Ile-Glu-, and 20 glutathione S-transferase (GST) variants, having Met-Xaa-Pro-Ile-sequence, were designed and synthesized. The MalE and GST proteins were purified by amylose-resin and glutathione columns, respectively, followed by analysis of their N-terminal sequences. These investigations revealed that sequence specificity and efficiency of the N-terminal Met (N-Met) elimination in the cell-free system are similar to those reported from investigations in cellular systems or in the wheat-embryo cell-free protein expression system in analytical scale (approximately 10 microg protein product per ml). Cleavage of the N-Met is basically determined by the penultimate amino acid in the polypeptide sequence. In the case of MalE, the cleavage was efficient when the penultimate residue was Ala, Cys, Gly, Pro, Ser or Thr. But, in the case of GST with Pro as the antepenultimate residue, the efficiency was significantly reduced when the penultimate residue was Gly or Thr. We also confirmed that substitution of the antepenultimate residue in MalE to Pro drastically reduced the efficiency of N-Met cleavage when the penultimate residue was Ala, Gly, Pro, Ser or Thr, indicating inhibitory effects of antepenultimate residue Pro on N-Met elimination. These results clarified sequence-specific functions of the endogenous N-terminal processing machinery in the scaled-up wheat-embryo cell-free translation system. 相似文献
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Consequences of amino-terminal deletions of preproparathyroid hormone signal sequence 总被引:1,自引:0,他引:1
M W Freeman K M Wiren A Rapoport M Lazar J T Potts H M Kronenberg 《Molecular endocrinology (Baltimore, Md.)》1987,1(9):628-638
PTH is initially synthesized as a larger precursor, containing a 25 amino acid signal sequence. Modification of cDNA encoding the hormone precursor resulted in the synthesis of proteins whose signal sequences were shortened at their amino termini. The effects of these mutations were analyzed using a cell-free translation system and rat pituitary GH4 cells in culture. Removal of the first six amino acids of the signal sequence had no effect on the efficiency or kinetics of protein processing as measured in the two assay systems. Mutants lacking 10 or 13 amino acids were not processed efficiently in the cells, nor were they translocated across microsomes in the cell-free translation system. These studies suggest that a modest change in the hydrophobic domain of the signal sequence, which might not have been predicted to alter function, led to a dramatic decline in signal activity. 相似文献
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Zeenko VV Wang C Majumder M Komar AA Snider MD Merrick WC Kaufman RJ Hatzoglou M 《RNA (New York, N.Y.)》2008,14(3):593-602
In vitro translation systems are used to investigate translational mechanisms and to synthesize proteins for characterization. Most available mammalian cell-free systems have reduced efficiency due to decreased translation initiation caused by phosphorylation of the initiation factor eIF2alpha on Ser51. We describe here a novel cell-free protein synthesis system using extracts from cultured mouse embryonic fibroblasts that are homozygous for the Ser51 to- Ala mutation in eIF2alpha (A/A cells). The translation efficiency of a capped and polyadenylated firefly luciferase mRNA in A/A cell extracts was 30-fold higher than in wild-type extracts. Protein synthesis in extracts from A/A cells was active for at least 2 h and generated up to 20 microg/mL of luciferase protein. Additionally, the A/A cell-free system faithfully recapitulated the selectivity of in vivo translation for mRNA features; translation was stimulated by a 5'-end cap (m7GpppN) and a 3'-end poly(A) tail in a synergistic manner. The system also showed similar efficiencies of cap-dependent and IRES-mediated translation (EMCV IRES). Significantly, the A/A cell-free system supported the post-translational modification of proteins, as shown by glycosylation of the HIV type-1 gp120 and cleavage of the signal peptide from beta-lactamase. We propose that cell-free systems from A/A cells can be a useful tool for investigating mechanisms of mammalian mRNA translation and for the production of recombinant proteins for molecular studies. In addition, cell-free systems from differentiated cells with the Ser51Ala mutation should provide a means for investigating cell type-specific features of protein synthesis. 相似文献
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The role of ribosomal protein S1 in the translation of mRNA containing an extended Shine-Dalgarno sequence was investigated. Using the toeprinting technique, formation of the ternary initiation complex between 30S subunits, both S1-depleted or treated with anti-S1 antibodies, and mini-mRNA containing the 9 nucleotide-long Shine-Dalgarno sequence was studied. It was concluded that the initiation of translation on mRNA with an extended Shine-Dalgarno sequence is S1-independent. It was demonstrated that S1-depleted ribosomes effectively translate the cro-mini-mRNA in a cell-free system. In contrast to cro-mini-mRNA, 30S subunits without protein S1 are inactive in ternary initiation complex formation with, and cell-free translation of, MS2 or fr phage RNAs and RNA protein III of phage fd. 相似文献
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T. Nojima T. Fujii K. Hosokawa A. Yotsumoto S. Shoji I. Endo 《Bioprocess and biosystems engineering》2000,22(1):13-17
Microbiochemical reactors having two inlet ports and one outlet port were fabricated on a silicon wafer by means of anisotropic etching in order to develop a parallel and automatic experimental system for cell-free translation. Using cell-free extract prepared from Escherichia coli, we tested the reactor for the translation of polyuridylic acid and MS2 phage RNA, and found that polypeptide and protein syntheses could be proceeded according to the genetic codes on the mRNAs. It indicates that the microfabricated reactor is useful for enzymatic reactions including complicated ones like cell-free translation. We also discuss the possibility of microsystems as advanced experimental tools for not only cell-free translation but also other various biochemical and biological research fields. 相似文献
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A highly effective cell-free system for protein synthesis was obtained from rabbit reticulocytes and for the first time used for synthesis of biologically active chicken interferon. The optimal conditions for translation of its mRNA were developed. The translation efficacy in the cell-free system was 10-50 times higher than that in the culture of heterologous cells. The higher the purity level of RNA, the higher the translation level. With respect to poly (A+) RNA sedimenting in the sucrose gradient 9S the efficacy reached 2560 units per 1 microgram of RNA. By the content of poly (A), sequences and rate of the sedimentation, mRNA of the chicken interferon was similar to that of the human fibroblast cell interferon. The possible translation of mRNA of the chicken interferon at low concentrations of exogenic potassium ions in the cell-free system is explained by production of interferon in infected cells where the concentration of the intracellular potassium significantly decreases which is indicative of the mRNA interferon similarity with virus templates. It was found that only albino New Zealand rabbits, but also chinchilla may be used for preparation of the cell-free protein synthesizing system. Various exogenic templates in the mRNA-dependent cell-free system prepared from reticulocyte nonfractionated lysate by treatment with micrococcal nuclease stimulated the protein synthesis by 7-15 times. 相似文献
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An amino-terminal methionine corresponding to a recombinant AUG initiation codon sometimes affects the functions of proteins. To test the performance of translation mediated by a dicistroviral internal ribosome entry site (IRES), which initiates protein synthesis with elongator tRNAs, we optimized the conditions for cell-free translation. Although the IRES is 188 nucleotides long, a further 50 nucleotides of the upstream sequence stabilized translation efficiency. Optimal ion concentrations were affected by the sequences of the constructs. In a wheat-germ system, IRES-mediated translation produced 78 microg/ml of firefly luciferase from the AUG-deleted sequence, suggesting that dicistroviral IRESs will be able to yield polypeptides with a specific N-terminal amino acid other than methionine. 相似文献
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EA Sogorin NE Shirokikh AM Ibragimova VD Vasiliev SCh Agalarov AS Spirin 《Biochemistry. Biokhimii?a》2012,77(4):342-345
Binding of mRNA leader sequences to ribosomes was studied in conditions of a cell-free translation system based on wheat germ
extract. Leader sequence of TMV mRNA (the so-called omega-RNA sequence) was able to bind simultaneously 80S ribosome and 40S
ribosomal subunit. It was found that nucleotide substitutions in omega-RNA resulting in destabilization of RNA structure have
no effect on the complex formation with both 80S ribosome and 40S ribosomal subunit. Leader sequence of globin mRNA is also
able to form a similar joint complex. It is supposed that the ability of mRNA leader sequences to bind simultaneously 80S
ribosome and 40S subunit is independent of leader nature and may reflect previously unknown eukaryotic mechanisms of translation
initiation. 相似文献
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Khan AM Miotto O Nascimento EJ Srinivasan KN Heiny AT Zhang GL Marques ET Tan TW Brusic V Salmon J August JT 《PLoS neglected tropical diseases》2008,2(8):e272