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Physiologically distinct subpopulations formed in Escherichia coli cultures in response to heat shock. Microbiol Res 2018; 209:33-42. [DOI: 10.1016/j.micres.2018.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 02/02/2018] [Accepted: 02/10/2018] [Indexed: 11/21/2022]
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2
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Screening and identification of genetic loci involved in producing more/denser inclusion bodies in Escherichia coli. Microb Cell Fact 2013; 12:43. [PMID: 23638724 PMCID: PMC3668246 DOI: 10.1186/1475-2859-12-43] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/29/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many proteins and peptides have been used in therapeutic or industrial applications. They are often produced in microbial production hosts by fermentation. Robust protein production in the hosts and efficient downstream purification are two critical factors that could significantly reduce cost for microbial protein production by fermentation. Producing proteins/peptides as inclusion bodies in the hosts has the potential to achieve both high titers in fermentation and cost-effective downstream purification. Manipulation of the host cells such as overexpression/deletion of certain genes could lead to producing more and/or denser inclusion bodies. However, there are limited screening methods to help to identify beneficial genetic changes rendering more protein production and/or denser inclusion bodies. RESULTS We report development and optimization of a simple density gradient method that can be used for distinguishing and sorting E. coli cells with different buoyant densities. We demonstrate utilization of the method to screen genetic libraries to identify a) expression of glyQS loci on plasmid that increased expression of a peptide of interest as well as the buoyant density of inclusion body producing E. coli cells; and b) deletion of a host gltA gene that increased the buoyant density of the inclusion body produced in the E. coli cells. CONCLUSION A novel density gradient sorting method was developed to screen genetic libraries. Beneficial host genetic changes could be exploited to improve recombinant protein expression as well as downstream protein purification.
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3
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Effective solubilization and single-step purification of Bacillus licheniformis alpha-amylase from insoluble aggregates. Folia Microbiol (Praha) 2010; 55:133-6. [PMID: 20490755 DOI: 10.1007/s12223-010-0020-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 10/22/2009] [Indexed: 10/19/2022]
Abstract
A high level expression of thermostable alpha-amylase gene from Bacillus licheniformis in Escherichia coli was obtained. The recombinant enzyme was mainly produced in the form of insoluble aggregates. The enzyme was solubilized without using denaturing agents and purified to homogeneity in a single step by ion exchange chromatography. The enzyme was purified 138-fold with a final yield of 349 %; the specific activity of the purified enzyme was 1343 U/mg.
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4
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Glascock CB, Weickert MJ. Using chromosomal lacIQ1 to control expression of genes on high-copy-number plasmids in Escherichia coli. Gene 1998; 223:221-31. [PMID: 9858738 DOI: 10.1016/s0378-1119(98)00240-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Transcription of the lac and the hybrid tac promoters is repressed by the lac repressor and induced by the non-metabolizable substrate IPTG. The degree of repression depends upon the ratio of LacI molecules in a cell to the DNA operator sites. In the absence of an inducer, repression of Ptac on a high-copy-number (hcn) plasmid was equivalent in strains containing lacIQ1 on the chromosome, or lacI+ on the plasmid, but not from strains with lacI+ or lacIQ only on the chromosome. Induction of Ptac on hcn plasmids in strains in which expression was controlled by lacIQ1 occurred at very low inducer concentrations (3-10microM IPTG) and reached levels significantly higher than in strains with lacI+ on the plasmid. Greater than 300-fold induction of a beta-LacZ fusion was observed, and >600-fold induction was estimated from recombinant hemoglobin synthesis. Transcription from PlacIQ1 initiated in the same point as PlacI+, but was 170-fold stronger, consistent with the lac repressor levels required to control LacI-regulated genes on hcn plasmids. The DNA sequence upstream of lacI was used to develop a simple PCR test to identify lacIQ1 by a characteristic 15-bp deletion. This deletion created a consensus -35 hexamer, responsible for the increased lacI transcription, and was easily detectable in a variety of strains. Using lacIQ1 hosts eliminates the requirement to maintain lacI on the plasmid to regulate gene expression on hcn expression plasmids.
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Affiliation(s)
- C B Glascock
- Somatogen, Inc., 2545 Central Avenue, Boulder, CO 80301, USA
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5
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Mousli M, Goyffon M, Billiald P. Production and characterization of a bivalent single chain Fv/alkaline phosphatase conjugate specific for the hemocyanin of the scorpion Androctonus australis. BIOCHIMICA ET BIOPHYSICA ACTA 1998; 1425:348-60. [PMID: 9795250 DOI: 10.1016/s0304-4165(98)00090-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A102 is a monoclonal antibody raised against the hemocyanin of the Tunisian scorpion Androctonus australis. It is directed against the subunit Aa6 and does not cross-react when tested against a variety of similar scorpion hemocyanins. Here, we report the construction of a plasmid encoding a recombinant enzyme-linked antigen-binding protein with the antigen-binding specificity of antibody A102. The DNA fragments encoding the variable domains of A102 were inserted into a prokaryotic expression vector so as to produce a single chain antibody variable fragment (scFv) fused to the bacterial alkaline phosphatase. The fusion protein preserved the IgG binding and alkaline phosphatase activities. Immunoelectron microscopic analysis showed that the recombinant protein bound antigen bivalently as is the case for natural antibodies. Crude preparations containing the conjugate were used in a rapid visual immunoassay for the specific detection of A. australis hemocyanin, using a droplet of hemolymph removed from live animals by puncture. The simplicity of the test made it suitable for the direct identification of animals belonging to this species. It could be useful in areas where A. australis, the most dangerous African scorpion, is found with other species from which it is not easy to distinguish using morphological criteria.
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Affiliation(s)
- M Mousli
- Muséum National d'Histoire Naturelle, 57 rue Cuvier, 75231 Paris cedex 05, France
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6
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Effect of inclusion bodies on the buoyant density of recombinant Escherichia coli. ACTA ACUST UNITED AC 1996. [DOI: 10.1007/bf00158938] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Rinas U, Bailey JE. Overexpression of bacterial hemoglobin causes incorporation of pre-beta-lactamase into cytoplasmic inclusion bodies. Appl Environ Microbiol 1993; 59:561-6. [PMID: 8382023 PMCID: PMC202144 DOI: 10.1128/aem.59.2.561-566.1993] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The expression of Vitreoscilla hemoglobin (VHb) in Escherichia coli JM101 (pRED2) causes the incorporation of the TEM beta-lactamase precursor into cytoplasmic inclusion bodies (IBs). Less pre-beta-lactamase is translocated and processed to its mature, periplasmic form in the strain coexpressing VHb than in the control strain E. coli JM101(pUC19) not expressing VHb. When cells are grown in a special fed-batch procedure, the formation of cytoplasmic IBs consisting of pre-beta-lactamase is also inducible in the control strain. Comparative microscopic and compositional analyses of IBs generated in E. coli JM101(pUC19) and JM101(pRED2) under identical growth conditions strongly suggest that pre-beta-lactamase and VHb coaggregate into common IBs in E. coli JM101 (pRED2).
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Affiliation(s)
- U Rinas
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125
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8
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Rinas U, Bailey JE. Protein compositional analysis of inclusion bodies produced in recombinant Escherichia coli. Appl Microbiol Biotechnol 1992; 37:609-14. [PMID: 1369400 DOI: 10.1007/bf00240735] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Culture conditions favouring the simultaneous formation of soluble protein and inclusion bodies (IBs) were chosen for producing the cytoplasmic protein beta-galactosidase or the periplasmic protein TEM-beta-lactamase. Soluble and insoluble cell fractions of Escherichia coli producing either beta-galactosidase or TEM-beta-lactamase were analyzed by one- and two-dimensional gel electrophoresis and subsequent silver staining or immunodetection of the recombinant protein. The results show that truncated fragments of the recombinant protein were not present in the soluble cell fraction but accumulate in the IB fraction. The presence of other cellular, non-plasmid-encoded proteins in IB preparations such as the outer membrane proteins OmpF, OmpC, and OmpA or the ribosomal subunit proteins L7/L12 was attributed to co-precipitation of cell-debris-associated components. Protein-folding enzymes were not detected in IB preparations. The specificity of in-vivo protein association in the formation of IBs and its implication on protein purification is discussed.
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Affiliation(s)
- U Rinas
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125
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9
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Rinas U, Tsai LB, Lyons D, Fox GM, Stearns G, Fieschko J, Fenton D, Bailey JE. Cysteine to serine substitutions in basic fibroblast growth factor: effect on inclusion body formation and proteolytic susceptibility during in vitro refolding. ACTA ACUST UNITED AC 1992; 10:435-40. [PMID: 1368488 DOI: 10.1038/nbt0492-435] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We have investigated the effect of cysteine to serine substitutions in human basic fibroblast growth factor (bFGF) on the formation of inclusion bodies in Escherichia coli. Using a temperature-sensitive expression, system, about 30% of human bFGF, which contains four cysteines at positions 26, 70, 88, and 93, is deposited into inclusion bodies. A single mutation at position 88 and a double mutation at positions 70 and 88 do not greatly alter the partition of bFGF into soluble and insoluble cell fractions. However, a single substitution of cysteine 70 by serine decreases the fraction of soluble bFGF significantly. When cysteines 26 and 93 (conserved among related growth factors) are replaced by serines, no soluble bFGF is formed in E. coli. Cysteine to serine substitutions also affect proteolytic susceptibility of bFGF during in vitro refolding from crude inclusion bodies. About 60% of human bFGF is lost to proteolytic degradation during in vitro refolding. Replacement of cysteines by serines increases the total recovery of bFGF, although more aggregates are formed during refolding. Ser-88-bFGF was expressed at the highest level, gave the highest soluble fraction in vivo, and exhibited the greatest fractional recovery and was recovered with the largest insoluble fraction after in vitro refolding. Thermal stability experiments at 42 degrees C and 70 degrees C revealed that cysteine to serine substitutions did not cause aggregation of the folded protein in vitro.
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Affiliation(s)
- U Rinas
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125
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10
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Abstract
Over-expression of recombinant proteins in microbial hosts results in the formation of active soluble protein or of insoluble aggregates (inclusion bodies). Efficient in vitro refolding strategies have been developed to reactivate inactive proteins from inclusion bodies. Co-expression of molecular chaperones may provide a tool to promote correct structure formation of recombinant proteins in vivo.
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Affiliation(s)
- J Buchner
- Institut für Biophysik and Biochemie, Universität Regensburg, Germany
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11
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Kiefhaber T, Rudolph R, Kohler HH, Buchner J. Protein aggregation in vitro and in vivo: a quantitative model of the kinetic competition between folding and aggregation. Nat Biotechnol 1991; 9:825-9. [PMID: 1367356 DOI: 10.1038/nbt0991-825] [Citation(s) in RCA: 241] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Protein aggregation is frequently observed as a major side-reaction of protein folding. We present quantitative models explaining the formation of aggregates during protein folding in vitro and in vivo on the basis of a kinetic competition between correct folding and aggregation reactions. Both models are in good agreement with experimental data. The model implies that, in vitro, the yield of native protein obtained upon refolding is determined by the rates of the competing first order folding and second order aggregation reactions. Therefore, a high protein concentrations aggregation dominates over folding and leads to the formation of insoluble protein. For in vivo protein synthesis, the model shows that the yield of native protein is only dependent on the rate of folding, on the rate of aggregation and on the rate of protein synthesis. In the cell, several mechanisms, including "folding helpers" seem to have evolved, which influence these processes and thereby prevent unproductive side reactions.
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Affiliation(s)
- T Kiefhaber
- Universität Bayreuth, Laboratorium für Biochemie, FRG
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12
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Mandrup S, Højrup P, Kristiansen K, Knudsen J. Gene synthesis, expression in Escherichia coli, purification and characterization of the recombinant bovine acyl-CoA-binding protein. Biochem J 1991; 276 ( Pt 3):817-23. [PMID: 2064616 PMCID: PMC1151077 DOI: 10.1042/bj2760817] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A synthetic gene encoding the 86 amino acid residues of mature acyl-CoA-binding protein (ACBP), and the initiating methionine was constructed. The synthetic gene was assembled from eight partially overlapping oligonucleotides. Codon usage and nucleotides surrounding the ATG translation-initiation codon were chosen to allow efficient expression in Escherichia coli as well as in yeast. The synthetic gene was inserted into the expression vector pKK223-3 and expressed in E. coli. In maximally induced cultures, recombinant ACBP constitutes 12-15% of total cellular protein. A fraction highly enriched for recombinant ACBP was obtained by extracting induced E. coli cells with 1 M-acetic acid. Recombinant ACBP was purified to homogeneity by successive use of gel-filtration chromatography, ion-exchange chromatography and reverse-phase h.p.l.c. Recombinant ACBP differed from native ACBP by lacking the N-terminal acetyl group. The acyl-CoA-binding characteristics of recombinant ACBP did not differ from those of native ACBP, and the two proteins showed the same ability to induce medium-chain acyl-CoA synthesis by goat mammary-gland fatty acid synthetase. It was concluded that the N-terminal acetyl group is not important for acyl-CoA binding.
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Affiliation(s)
- S Mandrup
- Institute of Biochemistry, Odense University, Denmark
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13
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Dowd DR, Lloyd RS. Site-directed mutagenesis of the T4 endonuclease V gene: the role of arginine-3 in the target search. Biochemistry 1989; 28:8699-705. [PMID: 2690947 DOI: 10.1021/bi00448a005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Endonuclease V, a pyrimidine dimer specific endonuclease in T4 bacteriophage, is able to scan DNA, recognize pyrimidine dimer photoproducts produced by exposure to ultraviolet light, and effectively incise DNA through a two-step mechanism at the damaged bases. The interaction of endonuclease V with nontarget DNA is thought to occur via electrostatic interactions between basic amino acids and the acidic phosphate DNA backbone. Arginine-3 was chosen as a potential candidate for involvement in this protein-nontarget DNA interaction and was extensively mutated to assess its role. The mutations include changes to Asp, Glu, Leu, and Lys and deleting it from the enzyme. Deletion of Arg-3 resulted in an enzyme that retained marginal levels of AP specificity, but no other detectable activity. Charge reversal to Glu-3 and Asp-3 results in proteins that exhibit AP-specific nicking and low levels of dimer-specific nicking. These enzymes are incapable of affecting cellular survival of repair-deficient Escherichia coli after irradiation. Mutations of Arg-3 to Lys-3 or Leu-3 also are unable to complement repair-deficient E. coli. However, these two proteins do exhibit a substantial level of in vitro dimer- and AP-specific nicking. The mechanism by which the Leu-3 and Lys-3 mutant enzymes locate pyrimidine dimers within a population of heavily irradiated plasmid DNA molecules appears to be significantly different from that for the wild-type enzyme. The wild-type endonuclease V processively incises all dimers on an individual plasmid prior to dissociation from that plasmid and subsequent reassociation with other plasmids, yet neither of these mutants exhibits any of the characteristics of this processive nicking activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D R Dowd
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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14
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Dowd DR, Lloyd RS. Biological consequences of a reduction in the non-target DNA scanning capacity of a DNA repair enzyme. J Mol Biol 1989; 208:701-7. [PMID: 2681789 DOI: 10.1016/0022-2836(89)90160-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Numerous DNA-interactive proteins have been shown to locate specific sequences within large domains of non-target DNA in vitro and in vivo by a one-dimensional diffusion mechanism; however, the biological significance of this process has not been evaluated. We have examined the biological consequences of sliding for the pyrimidine dimer-specific DNA repair enzyme T4 endonuclease V, an enzyme which scans non-target DNA both in vitro and in vivo. An endonuclease V mutant was constructed whose only altered biochemical characteristic, measured in vitro, was a loss in its ability to slide on non-target DNA. In contrast to the native enzyme, when the mutated endonuclease V was expressed in DNA repair-deficient Escherichia coli, no enhanced ultraviolet survival was conferred. These results suggest that the mechanisms which DNA-interactive proteins employ to enhance the probability of locating their target sequences are of significant biological importance.
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Affiliation(s)
- D R Dowd
- Department of Biochemistry, Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, TN 37232
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15
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Psallidopoulos MC, Seth A, Dubois GC, Fisher RJ, Papas TS. Expression and characterization of a protein encoded by the human c-myc exon 1 in Escherichia coli. GENE ANALYSIS TECHNIQUES 1989; 6:47-56. [PMID: 2524439 DOI: 10.1016/0735-0651(89)90010-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Our previously reported data from DNA sequence studies of the c-myc locus show that the human c-myc exon 1 has an open reading frame capable of encoding a protein of 188 amino acid residues. To confirm the presence of the open reading frame, we constructed a recombinant vector (pMCP60) that contains a segment of the lambda cII translational initiation region, a portion of the N-terminus of the v-mos gene, and 639 base pairs of the first exon of the human c-myc gene. pMCP60 expresses a 38 kilodalton tripartate protein (cII-mos-myc), which was purified by high-pressure liquid chromatography. The presence of myc exon 1 sequences in the cII-mos-myc fusion protein was confirmed by partial amino acid sequence analysis. These experiments further establish that the first exon of the human c-myc gene contains an open reading frame capable of expressing a protein in Escherichia coli.
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Affiliation(s)
- M C Psallidopoulos
- Laboratory of Molecular Oncology, National Cancer Institute, Frederick, Maryland 21701-1013
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16
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Kopetzki E, Schumacher G, Buckel P. Control of formation of active soluble or inactive insoluble baker's yeast alpha-glucosidase PI in Escherichia coli by induction and growth conditions. MOLECULAR & GENERAL GENETICS : MGG 1989; 216:149-55. [PMID: 2659969 DOI: 10.1007/bf00332244] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Using standard growth conditions (LB medium, 37 degrees C, induction with 5 mM IPTG) yeast alpha-glucosidase PI expressed under the control of the regulated tac-hybrid promoter results in the synthesis of insoluble aggregated alpha-glucosidase granules in Escherichia coli. Under these conditions active soluble alpha-glucosidase amounts to less than 1% of the heterologously produced protein. However, the amount of soluble active alpha-glucosidase was dramatically increased when the strong tac-hybrid promoter was to a limited extent induced. This was achieved at concentrations of 0.01 mM IPTG or of 1% lactose or lower in a lactose-permease deficient host strain containing the lacIq repressor gene on an R-plasmid. The formation of active soluble alpha-glucosidase was almost 100% when E. coli cells induced in this manner were cultivated under conditions that reduced growth rate, i.e. at decreased temperature, extreme pH values or in minimal and complete media supplemented with different carbon sources.
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Affiliation(s)
- E Kopetzki
- Boehringer Mannheim GmbH, Department of Genetics, Penzberg, Federal Republic of Germany
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17
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Sato N, Kawazoe I, Tamai T, Inoue Y, Murata K, Kimura S, Nonaka M, Kimura A. Purification and characterization of recombinant tuna growth hormone produced in Escherichia coli. ACTA ACUST UNITED AC 1989. [DOI: 10.1016/0922-338x(89)90051-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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18
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Kane JF, Hartley DL. Formation of recombinant protein inclusion bodies in Escherichia coli. Trends Biotechnol 1988. [DOI: 10.1016/0167-7799(88)90065-0] [Citation(s) in RCA: 198] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Single–Cell Light Scatter as a Probe of Refractile Body Formation in Recombinant Escherichia Coli. Nat Biotechnol 1988. [DOI: 10.1038/nbt0488-423] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Affiliation(s)
- G A Codd
- Department of Biological Sciences, University of Dundee, UK
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21
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Honda S, Sugino H, Nishi K, Nara K, Kakinuma A. Purification of human leukocyte interferon A derived from Escherichia coli: An aging process to prevent the formation of its oligomers. J Biotechnol 1987. [DOI: 10.1016/0168-1656(87)90069-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Owens RJ, Baralle FE. Mapping the collagen-binding site of human fibronectin by expression in Escherichia coli. EMBO J 1986; 5:2825-30. [PMID: 3024962 PMCID: PMC1167230 DOI: 10.1002/j.1460-2075.1986.tb04575.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The collagen-binding domain of human fibronectin has been expressed as a cro/beta-galactosidase fusion protein in Escherichia coli. The hybrid polypeptide was recognized by an anti-(human plasma fibronectin) serum and bound specifically to gelatin-Sepharose. The collagen-binding region was subdivided by constructing a series of overlapping bacterial expression plasmids. The fusion proteins produced by these constructs were analysed for gelatin-binding activity. The results indicate that the binding site lies within an approximately 12.5 kd fragment of fibronectin, and show that the following 14 amino acid sequence is critical for gelatin-binding activity: Ala-Ala-His-Glu-Glu-Ile-Cys-Thr-Thr-Asn-Glu-Gly-Val-Met. This sequence links the second type II homology unit with the adjacent type I repeat in the amino-terminal third of the fibronectin molecule.
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24
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Rapid purification of bacterially expressed fusion proteins by high-performance liquid chromatography methods. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0735-0651(86)90012-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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25
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Docherty AJ, Bodmer MW, Angal S, Verger R, Riviere C, Lowe PA, Lyons A, Emtage JS, Harris TJ. Molecular cloning and nucleotide sequence of rat lingual lipase cDNA. Nucleic Acids Res 1985; 13:1891-903. [PMID: 3839077 PMCID: PMC341123 DOI: 10.1093/nar/13.6.1891] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purified rat lingual lipase (EC3113), a glycoprotein of approximate molecular weight 52,000, was used to generate polyclonal antibodies which were able to recognise the denatured and deglycosylated enzyme. These immunoglobulins were used to screen a cDNA library prepared from mRNA isolated from the serous glands of rat tongue cloned in E. coli expression vectors. An almost full length cDNA clone was isolated and the nucleotide and predicted amino acid sequence obtained. Comparison with the N-terminal amino acid sequence of the purified enzyme confirmed the identity of the cDNA and indicated that there was a hydrophobic signal sequence of 18 residues. The amino acid sequence of mature rat lingual lipase consists of 377 residues and shares little homology with porcine pancreatic lipase apart from a short region containing a serine residue at an analogous position to the ser 152 of the porcine enzyme.
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Subbalakshmi GY, Murthy CR. Effects of methionine sulfoximine on the enzymes of glutamate metabolism in isolated astrocytes of rat brain. Biochem Pharmacol 1983; 32:3695-700. [PMID: 6140923 DOI: 10.1016/0006-2952(83)90137-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The enzymes of glutamate metabolism were estimated in astrocytes isolated from brains of normal rats and those injected with the potent convulsant, methionine sulfoximine (MSO), which inhibits glutamine synthetase and induces Alzheimer type II astrocytosis. The wet weight, dry weight; contents of DNA, RNA, protein and the activities of glutamate dehydrogenase and aspartate aminotransferase were elevated following MSO administration. The metabolic effects of MSO were found to be different from those of ammonia wherein a fall in the activity of glutamate dehydrogenase and an increase in the activity of glutamine synthetase was noticed. Based on these results it is suggested that there might be an inverse relationship in the functioning of these two enzymes. Such a relationship would help in preventing the depletion of energy pools in a given cellular compartment during ammonia detoxification.
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