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Characterization of a Cellulomonas fimi exoglucanase/xylanase-endoglucanase gene fusion which improves microbial degradation of cellulosic biomass. Enzyme Microb Technol 2016; 93-94:113-121. [DOI: 10.1016/j.enzmictec.2016.08.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 11/17/2022]
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2
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Lakhundi SS, Duedu KO, Cain N, Nagy R, Krakowiak J, French CE. Citrobacter freundii as a test platform for recombinant cellulose degradation systems. Lett Appl Microbiol 2016; 64:35-42. [PMID: 27617802 DOI: 10.1111/lam.12668] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/27/2016] [Accepted: 09/08/2016] [Indexed: 01/03/2023]
Abstract
Cellulosic biomass represents a huge reservoir of renewable carbon, but converting it into useful products is challenging. Attempts to transfer cellulose degradation capability to industrially useful micro-organisms have met with limited success, possibly due to poorly understood synergy between multiple cellulases. This is best studied by co-expression of many combinations of cellulases and associated proteins. Here, we describe the development of a test platform based on Citrobacter freundii, a cellobiose-assimilating organism closely related to Escherichia coli. Standard E. coli cloning vectors worked well in Cit. freundii. Expression of cellulases CenA and Cex of Cellulomonas fimi in Cit. freundii gave recombinant strains which were able to grow at the expense of cellulosic filter paper or microcrystalline cellulose (Avicel) in a mineral medium supplemented with a small amount of yeast extract. Periodic physical agitation of the cultures was highly beneficial for growth at the expense of filter paper. This provides a test platform for the expression of combinations of genes encoding biomass-degrading enzymes to develop effective genetic cassettes for degradation of different biomass streams. SIGNIFICANCE AND IMPACT OF THE STUDY Biofuels have been shown to be the best sustainable and alternative source of fuel to replace fossil fuels. Of the different types of feedstocks used for producing biofuels, lignocellulosic biomass is the most abundant. Converting this biomass to useful products has met with little success. Different approaches are being used and microbial platforms are the most promising and sustainable method. This study shows that Citrobacter freundii is a better test platform than Escherichia coli for testing various combinations of cellulases for the development of microbial systems for biomass conversion.
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Affiliation(s)
- S S Lakhundi
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Department of Biological and Biomedical Sciences, Aga Khan University, Karachi, Pakistan
| | - K O Duedu
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,School of Basic & Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - N Cain
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - R Nagy
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - J Krakowiak
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - C E French
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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3
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Saccharification of cellulose by recombinant Rhodococcus opacus PD630 strains. Appl Environ Microbiol 2013; 79:5159-66. [PMID: 23793636 DOI: 10.1128/aem.01214-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The noncellulolytic actinomycete Rhodococcus opacus strain PD630 is the model oleaginous prokaryote with regard to the accumulation and biosynthesis of lipids, which serve as carbon and energy storage compounds and can account for as much as 87% of the dry mass of the cell in this strain. In order to establish cellulose degradation in R. opacus PD630, we engineered strains that episomally expressed six different cellulase genes from Cellulomonas fimi ATCC 484 (cenABC, cex, cbhA) and Thermobifida fusca DSM43792 (cel6A), thereby enabling R. opacus PD630 to degrade cellulosic substrates to cellobiose. Of all the enzymes tested, five exhibited a cellulase activity toward carboxymethyl cellulose (CMC) and/or microcrystalline cellulose (MCC) as high as 0.313 ± 0.01 U · ml(-1), but recombinant strains also hydrolyzed cotton, birch cellulose, copy paper, and wheat straw. Cocultivations of recombinant strains expressing different cellulase genes with MCC as the substrate were carried out to identify an appropriate set of cellulases for efficient hydrolysis of cellulose by R. opacus. Based on these experiments, the multicellulase gene expression plasmid pCellulose was constructed, which enabled R. opacus PD630 to hydrolyze as much as 9.3% ± 0.6% (wt/vol) of the cellulose provided. For the direct production of lipids from birch cellulose, a two-step cocultivation experiment was carried out. In the first step, 20% (wt/vol) of the substrate was hydrolyzed by recombinant strains expressing the whole set of cellulase genes. The second step was performed by a recombinant cellobiose-utilizing strain of R. opacus PD630, which accumulated 15.1% (wt/wt) fatty acids from the cellobiose formed in the first step.
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Ong E, Gilkes NR, Miller RC, Warren RA, Kilburn DG. The cellulose-binding domain (CBD(Cex)) of an exoglucanase from Cellulomonas fimi: production in Escherichia coli and characterization of the polypeptide. Biotechnol Bioeng 2010; 42:401-9. [PMID: 18613043 DOI: 10.1002/bit.260420402] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The gene fragment encoding the cellulose-binding domain (CBD) of an exoglucanase (Cex) from Cellulomonas fimi was subcloned and expressed in Escherichia coli. Transcription from the lac promoter coupled with translation from a consensus prokaryotic ribosome binding site led to the production of large quantities of CBD(Cex) (up to 25% total soluble cell protein). The polypeptide leaked into the culture supernatant (up to 50 mg . L(-1)), facilitating one-step purification by affinity chromatography on cellulose. The 11-kDa polypeptide reacted with Cex antiserum. Absence of free thiols indicated that the two Cys residues of CBD(Cex) form a disulfide bridge. It had the same N-terminal amino acid sequence as CBD(Cex) prepared from Cex by proteolysis, plus two additional N-terminal amino acid residues (Ala and Ser) encoded by the Nhel site introduced during plasmid construction. CBD(Cex) bound to a variety of beta-1, 4-glycans with different affinities and saturation levels. Adsorption to bacterial microcrystalline cellulose was dependent on the temperature, but not on the pH.
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Affiliation(s)
- E Ong
- Department of Microbiology and Protein Engineering Network of Centres of Excellence, University of British Columbia, Vancouver, British Columbia, Canada
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Cockburn DW, Vandenende C, Clarke AJ. Modulating the pH−Activity Profile of Cellulase by Substitution: Replacing the General Base Catalyst Aspartate with Cysteinesulfinate in Cellulase A from Cellulomonas fimi. Biochemistry 2010; 49:2042-50. [DOI: 10.1021/bi1000596] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Darrell W. Cockburn
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Chris Vandenende
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Anthony J. Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Hasenwinkle D, Jervis E, Kops O, Liu C, Lesnicki G, Haynes CA, Kilburn DG. Very high-level production and export in Escherichia coli of a cellulose binding domain for use in a generic secretion-affinity fusion system. Biotechnol Bioeng 2009; 55:854-63. [PMID: 18636596 DOI: 10.1002/(sici)1097-0290(19970920)55:6<854::aid-bit4>3.0.co;2-f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A novel expression vector pTugA, previously constructed in our laboratory, was modified to provide kanamycin resistance (pTugK) and used to direct the synthesis of polypeptides as fusions with the C- or N-terminus of a cellulose binding domain which serves as the affinity tag in a novel secretion-affinity fusion system. Fed-batch fermentation strategies were applied to production in recombinant E. coli TOPP5 of the cellulose binding domain (CBD) from the Cellulomonas fimi cellulase Cex. The pTugK expression vector, which codes for the Cex leader sequence that directs the recombinant protein to the periplasm of E. coli, was shown to remain stable at very high-cell densities. Recombinant cell densities in excess of 90 g (dry cell weight)/L were achieved using media and feed solutions optimized using a 2(n) factorial design. Optimization of inducer (isophenyl-thio-beta-D-galactopyranoside) concentration and the time of induction led to soluble, fully active CBD(Cex) production levels in excess of 8 g/L.
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Affiliation(s)
- D Hasenwinkle
- Biotechnology Laboratory, Protein Engineering Network of Centres of Excellence, and The Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
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7
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Production and purification of the isolated family 2a carbohydrate-binding module from Cellulomonas fimi. Protein Expr Purif 2009; 64:63-8. [DOI: 10.1016/j.pep.2008.10.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/16/2008] [Accepted: 10/17/2008] [Indexed: 11/23/2022]
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8
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Lau AT, Wong WK. Purification and characterization of a major secretory cellobiase, Cba2, from Cellulomonas biazotea. Protein Expr Purif 2001; 23:159-66. [PMID: 11570858 DOI: 10.1006/prep.2001.1486] [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: 11/22/2022]
Abstract
A novel cellobiase (Cba2) was purified from the culture supernatant of Cellulomonas biazotea and characterized. Cba2 appeared to be a major secretory cellobiase in C. biazotea as its enzymatic activity was estimated to represent over 40% of the total extracellular beta-glucosidase activity. The enzyme was purified over 260-fold subsequent to ammonium sulfate precipitation, gel-filtration chromatography, anion-exchange chromatography, and reversed-phase high-performance liquid chromatography. Cba2 was shown by SDS-PAGE to have a large molecular mass of 109 kDa, which makes it one of the largest secretory cellobiases characterized. Its homogeneity was confirmed by N-terminal amino acid sequencing. The K(m) and V(max) values were 0.025 mM and 0.0048 mM min(-1), respectively, for the Cba2 hydrolysis of p-nitrophenyl-beta-d-glucopyranoside, and 0.73 mM and 0.00033 mM min(-1), respectively, for the hydrolysis of cellobiose (at 37 degrees C and pH 7.0). The purified enzyme has a pH optimum of 4.8 and the optimum temperature for activity is 70 degrees C. In view of the secretory nature of Cba2 and the fact that it is a major component of secretory cellobiases of C. biazotea, it is potentially important in the enzymatic degradation of cellulose, and its availability as a recombinant protein may facilitate the studies of its biotechnological applications.
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Affiliation(s)
- A T Lau
- Department of Biochemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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Abe J, Ushijima C, Hizukuri S. Expression of the isoamylase gene of Flavobacterium odoratum KU in Escherichia coli and identification of essential residues of the enzyme by site-directed mutagenesis. Appl Environ Microbiol 1999; 65:4163-70. [PMID: 10473430 PMCID: PMC99755 DOI: 10.1128/aem.65.9.4163-4170.1999] [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: 11/20/2022] Open
Abstract
The isoamylase gene from Flavobacterium odoratum KU was cloned into and expressed in Escherichia coli JM109. The promoter of the gene was successful in E. coli, and the enzyme produced was excreted into the culture medium, depending on the amount of the enzyme expressed. The enzyme found in the culture medium showed almost the same M(r), heat-inactivating constant, and N-terminal sequence as those of the enzyme accumulated in the periplasmic space. This result indicated that the enzyme accumulated in an active form at the periplasm was transported out of the cell. The primary sequence of the enzyme, which was deduced from its nucleotide sequence, showed that the mature enzyme consisted of 741 amino acid residues. By changing five possible residues to Ala independently, it was found that Asp-374, Glu-422, and Asp-497 were essential. The sequences around those residues were highly conserved in isoamylases of different origins and the glycogen operon protein X, GlgX. The comparison of the distance between these essential residues with those of various amylases suggested that the bacterial and plant isoamylase but not GlgX had a longer fourth loop than the other amylases. This longer fourth loop had a possible role in accommodating the long branched chains of native glycogens and starches.
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Affiliation(s)
- J Abe
- Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Korimoto-1-21-24, Kagoshima 890, Japan.
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10
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Lam KH, Chow KC, Wong WK. Construction of an efficient Bacillus subtilis system for extracellular production of heterologous proteins. J Biotechnol 1998; 63:167-77. [PMID: 9803531 DOI: 10.1016/s0168-1656(98)00041-8] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An efficient expression/secretion vector, designated pM2Veg, was constructed for extracellular production of heterologous proteins in Bacillus subtilis. To construct pM2Veg, a synthetic cassette, the Veg cassette carrying: (1) the strong vegetative vegI promoter from B. subtilis, (2) the Escherichia coli lac operator, (3) the B. subtilis consensus ribosome-binding site, (4) the Staphylococcal protein A leader sequence, (5) a cloning region for insertion of foreign genes, (6) translational stop codons in all three reading frames, and (7) the gnt transcriptional terminator, was cloned into a derivative of the stable pRB373 B. subtilis/E. coli shuttle plasmid, the pM2 vector. The application of pM2Veg to effect secretory production of heterologous proteins was illustrated using two widely different proteins: the endoglucanase (Eng) encoded by the cenA gene of Cellulomonas fimi and human epidermal growth factor (hEGF). Levels of Eng and hEGF measured in culture supernatant samples of B. subtilis transformants harboring recombinant constructs formed between pM2Veg and the cenA and hEGF genes were 8.3 U ml-1 and 7.0 mg l-1, respectively. The Eng activity is more than four times higher than the yield from the best cenA recombinant construct previously reported, and the hEGF data represents the first successful expression of the factor in B. subtilis.
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Affiliation(s)
- K H Lam
- Department of Biochemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong
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11
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Wong WK, Ali A, Chan WK, Ho V, Lee NT. The cloning, expression and characterization of a cellobiase gene encoding a secretory enzyme from Cellulomonas biazotea. Gene X 1998; 207:79-86. [PMID: 9511746 DOI: 10.1016/s0378-1119(97)00608-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A 4.7-kb DNA insert encoding a secretory cellobiase (Cba) was cloned from Cellulomonas biazotea in Escherichia coli using an excretion vector, pM. Host cells transformed with the recombinant construct, designated pBZ4.7, were able to utilize cellobiose as the sole carbon source. Part of the Cba activity encoded by pBZ4.7 could be detected in the periplasm and even in the culture supernatant. The Cba protein was purified from the culture supernatant and analyzed by SDS-PAGE to have an apparent M(r) of 86,000. The insert consisted of two PstI fragments with lengths of 0.75 and 3.95 kb, both of which were found to be crucial for expressing the Cba activity. Sequencing of the first 3.95 kb of the insert revealed that the coding sequence for Cba, designated the cba gene, was 2484 bp long. Comparison of the deduced Cba sequence with those of published beta-glucosidases revealed a potential active site located at the N-terminal portion of the former. The cba gene has a high G + C content of 76.4% and is flanked by a putative ribosome-binding site and potential transcriptional termination signals upstream and downstream from its coding sequence, respectively.
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Affiliation(s)
- W K Wong
- Department of Biochemistry, Hong Kong University of Science and Technology, Kowloon, Hong Kong.
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12
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Wood BE, Beall DS, Ingram LO. Production of recombinant bacterial endoglucanase as a co-product with ethanol during fermentation using derivatives ofEscherichia coli KO11. Biotechnol Bioeng 1997; 55:547-55. [DOI: 10.1002/(sici)1097-0290(19970805)55:3<547::aid-bit12>3.0.co;2-d] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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Lam TL, Wong RS, Wong WK. Enhancement of extracellular production of a Cellulomonas fimi exoglucanase in Escherichia coli by the reduction of promoter strength. Enzyme Microb Technol 1997; 20:482-8. [PMID: 9134758 DOI: 10.1016/s0141-0229(96)00203-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The enzymatic approach to the treatment of cellulosic wastes depends on the availability of cost-effective means for the production of cellulases. We have engineered an excretion construct, tacIQpar8cex, to investigate the extracellular production of a Cellulomonas fimi exoglucanase (Exg) in Escherichia coli. The overall yield of Exg expressed by the culture of JM101 (tacIQpar8cex) was 2-11 times higher than that obtained using other systems. Over 20% of the activity was detected in the medium. When the culture was induced with IPTG, the overall production of Exg dropped dramatically. The lower yield was found to be caused by both rapid cell death and plasmid curing. A derivative of tacIQpar8cex containing the weaker lacUV5 promoter, designated lacUV5par8cex, was constructed to enhance excretion of Exg from strain JM101. Even with IPTG induction, the JM101 (lacUV5par8cex) culture was found to show a high level of cell viability and plasmid stability as well as the ability to provide efficient expression and excretion of Exg. Upon IPTG induction for 12 h, the activity and specific activity of the excreted Exg obtained from the lacUV5par8cex construct were 143 U ml-1 and 793 U mg-1 protein, respectively, which are 2-5 times higher than that detected from the tacIQpar8cex construct and from the best construct expressing the same gene reported previously.
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Affiliation(s)
- T L Lam
- Department of Biochemistry, Hong Kong University of Science & Technology, Kowloon, Hong Kong
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14
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Graham RW, Greenwood JM, Warren RA, Kilburn DG, Trimbur DE. The pTugA and pTugAS vectors for high-level expression of cloned genes in Escherichia coli. Gene X 1995; 158:51-4. [PMID: 7789810 DOI: 10.1016/0378-1119(95)00165-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Plasmids pTugA and pTugAS, designed for expression of cloned genes in Escherichia coli, possess the features of high-level inducible transcription, enhanced RNA translation, portability, high copy number, stability and versatility. In addition, pTugAS can be used to produce fusion proteins comprising a target protein and a cellulose-binding domain. Such fusion proteins can be purified in a single step by affinity chromatography on cellulose. Expression of two model gene fusions using the pTug plasmids resulted in yields of 500 mg of intracellular and 250 mg of extracellular recombinant protein per liter.
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Affiliation(s)
- R W Graham
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Greenwood JM, Gilkes NR, Miller RC, Kilburn DG, Warren RAJ. Purification and processing of cellulose-binding domain-alkaline phosphatase fusion proteins. Biotechnol Bioeng 1994; 44:1295-305. [DOI: 10.1002/bit.260441105] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Coutinho J, Gilkes N, Kilburn D, Warren R, Miller R. The nature of the cellulose-binding domain effects the activities of a bacterial endoglucanase on different forms of cellulose. FEMS Microbiol Lett 1993. [DOI: 10.1111/j.1574-6968.1993.tb06516.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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17
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Schofield LR, Daniel RM. Purification and properties of a beta-1,4-xylanase from a cellulolytic extreme thermophile expressed in Escherichia coli. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1993; 25:609-17. [PMID: 8467959 DOI: 10.1016/0020-711x(93)90670-a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
1. An endoxylanase (EC 3.2.1.8) was purified from an Escherichia coli strain carrying a xylanase gene from the extreme thermophile "Caldocellum saccharolyticum" strain Tp8T6.3.3.1. It was found to have an M(r) of 42,000 and an isoelectric point of approx. 5.0. 2. The enzyme showed optimum activity at pH 5.0-7.7 and had an activation energy of 44 kJ mol-1. It was stable at room temperature at pH 4.5-11.5 in the presence of 0.5 mg ml-1 bovine serum albumin. The half-life of the enzyme at 75 degrees C was 20 min at pH 6.0 in the presence of 0.5 mg ml-1 bovine serum albumin. 3. The xylanase had highest activity on oat spelts xylan, releasing xylobiose and some xylotriose. The Km for oat spelts xylan was 0.021% (w/v) at pH 6.0. 4. The enzyme had high activity on sugar cane bagasse hemicelluloses A and B, lower activity on larchwood xylan and also hydrolysed carboxymethylcellulose, 4-methylumbelliferyl beta-D-cellobioside and p-nitrophenyl beta-D-cellobioside, but could not hydrolyse xylobiose. 5. It showed transferase activity on p-nitrophenyl beta-D-xylopyranoside. Xylose did not inhibit the enzyme.
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Affiliation(s)
- L R Schofield
- Microbial Biochemistry and Biotechnology Research Unit, University of Waikato, Hamilton, New Zealand
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18
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Gilkes N, Jervis E, Henrissat B, Tekant B, Miller RC, Warren R, Kilburn D. The adsorption of a bacterial cellulase and its two isolated domains to crystalline cellulose. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50488-4] [Citation(s) in RCA: 187] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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19
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Shen H, Schmuck M, Pilz I, Gilkes N, Kilburn D, Miller R, Warren R. Deletion of the linker connecting the catalytic and cellulose-binding domains of endoglucanase A (CenA) of Cellulomonas fimi alters its conformation and catalytic activity. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)99167-2] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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20
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Modification of the properties of a Ruminococcus albus endo-1,4-beta-glucanase by gene truncation. J Bacteriol 1991; 173:636-41. [PMID: 1987156 PMCID: PMC207054 DOI: 10.1128/jb.173.2.636-641.1991] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
An endo-1,4-beta-glucanase (EgI) gene isolated from Ruminococcus albus was deleted at the 5'-flanking region by gene truncation or at the 3'-flanking region by insertion of an omega (omega) fragment with a universal stop codon at the EcoRI or BamHI site. These modified genes were integrated into pUC vectors to construct chimera plasmids for Escherichia coli. The truncated EgIs were produced from transformants (E. coli) harboring the chimera plasmids. An EgI with a 15-amino-acid N-terminal deletion exibited higher activity at lower pH and temperature compared with the activity of the original EgI. The EgIs with 59- and 75-amino-acid deletions from the N and C terminals, respectively, had no activity, indicating that both terminal moieties are essential for enzyme activity.
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21
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Bingle WH, Smit J. High-level expression vectors for Caulobacter crescentus incorporating the transcription/translation initiation regions of the paracrystalline surface-layer-protein gene. Plasmid 1990; 24:143-8. [PMID: 2096400 DOI: 10.1016/0147-619x(90)90016-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A number of plasmid vectors were constructed for high-level gene expression in the dimorphic gram-negative bacterium Caulobacter crescentus. These vectors incorporate the transcription and translation initiation regions of the C. crescentus CB15A rsaA gene, which codes for the abundantly synthesized protein comprising the bacterium's paracrystalline surface layer. The expression vectors are based on the broad-host-range IncQ plasmid RSF1010 (R300B) and incorporate the rsaA promoter and transcription start site. Some vectors also contain translation initiation information; these can result in the addition of as little as a single glycine residue to the protein encoded by the cloned segment. The vectors can be introduced into C. crescentus by electroporation at high frequency (ranging up to 10(6)-10(7) electroporants/micrograms DNA with surface-layer-deficient mutant C. crescentus CB2A) or conjugal transfer. They range in size from 10 to 12 kb, specify either chloramphenicol or kanamycin resistance, and possess the restriction sites EcoRI, BamHI, KpnI, and SstI for cloning genes downstream of the rsaA gene sequences. For a number of the vectors, the complete nucleotide sequence is known. A comparison was made between the expression of an endoglucanase gene from these plasmids in C. crescentus CB2A and CB15A and similar constructions under the control of lacZ alpha transcription and translation initiation signals carried on a pUC9 vector in an Escherichia coli host. The two expression systems compared favorably; cell lysates prepared from C. crescentus CB2A exhibited 40% of the endoglucanase activity of similarly prepared lysates from E. coli JM101. Lysates prepared from C. crescentus CB15A exhibited only 8% of the endoglucanase activity of E. coli lysates.
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Affiliation(s)
- W H Bingle
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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22
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Din N, Beck CF, Miller RC, Kilburn DG, Warren RA. Expression of the Cellulomonas fimi cellulase genes cex and cenA from the divergent tet promoters of transposon Tn10. Arch Microbiol 1990; 153:129-33. [PMID: 2154164 DOI: 10.1007/bf00247809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A cartridge was constructed which contained the divergent tet promoters of transposon Tn10 between an exoglucanase gene (cex) and an endoglucanase gene (cenA) of Cellulomonas fimi. When carried in a broad-host-range vector, the cartridge gave expression of cex and cenA in Escherichia coli, Rhodobacter capsulatus and Klebsiella pneumoniae.
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Affiliation(s)
- N Din
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Gilkes NR, Kilburn DG, Miller RC, Warren RA. Structural and functional analysis of a bacterial cellulase by proteolysis. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)84644-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Greenwood JM, Gilkes NR, Kilburn DG, Miller RC, Warren RA. Fusion to an endoglucanase allows alkaline phosphatase to bind to cellulose. FEBS Lett 1989; 244:127-31. [PMID: 2494059 DOI: 10.1016/0014-5793(89)81177-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Endoglucanase CenA of Cellulomonas fimi comprises an N-terminal cellulose-binding domain and a C-terminal catalytic domain joined together by a sequence of 23 proline and threonine residues (the Pro-Thr box). The domains function independently when separated by proteolysis. TnphoA has been used to generate cenA'-'phoA fusions. CenA'-'PhoA fusion polypeptides which contain the entire cellulose-binding domain of CenA bind to cellulose, allowing their purification from periplasmic extracts in a single, facile step. This result has implications for purification or immobilisation of chimeric proteins on a cheap cellulose matrix.
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Affiliation(s)
- J M Greenwood
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Suominen I, Käpylä J, Tilgmann C, Glumoff V, Mäntsälä P. Suppression of growth defects of α-amylase secreting Escherichia coliby signal sequence fusion. FEMS Microbiol Lett 1988. [DOI: 10.1111/j.1574-6968.1988.tb02789.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Gilkes NR, Warren RA, Miller RC, Kilburn DG. Precise excision of the cellulose binding domains from two Cellulomonas fimi cellulases by a homologous protease and the effect on catalysis. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(19)81530-2] [Citation(s) in RCA: 136] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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