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Lin X, Dong L, Yu D, Wang B, Pan L. High-level expression and characterization of the thermostable leucine aminopeptidase Thelap from the thermophilic fungus Thermomyces lanuginosus in Aspergillus niger and its application in soy protein hydrolysis. Protein Expr Purif 2020; 167:105544. [DOI: 10.1016/j.pep.2019.105544] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 11/19/2019] [Accepted: 11/19/2019] [Indexed: 10/25/2022]
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Hamilton M, Consiglio AL, MacEwen K, Shaw AJ, Tsakraklides V. Identification of a Yarrowia lipolytica acetamidase and its use as a yeast genetic marker. Microb Cell Fact 2020; 19:22. [PMID: 32024536 PMCID: PMC7003347 DOI: 10.1186/s12934-020-1292-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/22/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Yarrowia lipolytica is an oleaginous yeast that can be genetically engineered to produce lipid and non-lipid biochemicals from a variety of feedstocks. Metabolic engineering of this organism usually requires genetic markers in order to select for modified cells. The potential to combine multiple genetic manipulations depends on the availability of multiple or recyclable selectable markers. RESULTS We found that Y. lipolytica has the ability to utilize acetamide as the sole nitrogen source suggesting that the genome contains an acetamidase gene. Two potential Y. lipolytica acetamidase gene candidates were identified by homology to the A. nidulans acetamidase amdS. These genes were deleted in the wild-type Y. lipolytica strain YB-392, and deletion strains were evaluated for acetamide utilization. One deletion strain was unable to grow on acetamide and a putative acetamidase gene YlAMD1 was identified. Transformation of YlAMD1 followed by selection on acetamide media and counterselection on fluoroacetamide media showed that YlAMD1 can be used as a recyclable genetic marker in Saccharomyces cerevisiae and Ylamd1Δ Y. lipolytica. CONCLUSIONS These findings add to our understanding of Y. lipolytica nitrogen utilization and expand the set of genetic tools available for engineering this organism, as well as S. cerevisiae.
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Affiliation(s)
| | | | - Kyle MacEwen
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
| | - A Joe Shaw
- Novogy, Inc., 85 Bolton Street, Cambridge, MA, 02140, USA
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3
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Chen X, Wang B, Pan L. Heterologous expression and characterization of Penicillium citrinum nuclease P1 in Aspergillus niger and its application in the production of nucleotides. Protein Expr Purif 2018; 156:36-43. [PMID: 30557611 DOI: 10.1016/j.pep.2018.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 12/10/2018] [Accepted: 12/13/2018] [Indexed: 12/15/2022]
Abstract
Nuclease P1 gene (nuc P1) which was cloned from Penicillium citrinum and expressed in A. niger Bdel4 with the low-background extracellular protein. The expression strategy of multi-copy nuc P1 in the A. niger with the linker of 2A peptide was applied to improve the enzyme activity of nuclease P1, the highest activity up to 77.6 U/mL. After Ni-chelate purification, the specific enzyme activity, the optimum temperature and pH were 32.4 U/mg, 65 °C and 5.3 respectively. The recombination nuclease P1 was activated by addition of Mg2+, Zn2+ and Cu2+, and inhibited by addition of Ca2+, Fe2+, Mn2+, Ni2+, Co2+, Mg2+, K+ and EDTA. Furthermore, the enzyme hydrolyses yeast RNA efficiently into 5'- nucleotides. Through enzymolysis, the highest concentration of nucleotides achieved 15.12 mg/mL, and 75U nuclease P1 is suitable amount should be added to the enzymolysis system.
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Affiliation(s)
- Xiaoyi Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, 510006, China
| | - Bin Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Guangzhou, 510006, China
| | - Li Pan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, Guangdong, 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Guangzhou, 510006, China.
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4
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Structural and functional characterization of ochratoxinase, a novel mycotoxin-degrading enzyme. Biochem J 2014; 462:441-52. [PMID: 24947135 DOI: 10.1042/bj20140382] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ochratoxin, with ochratoxin A as the dominant form, is one of the five major mycotoxins most harmful to humans and animals. It is produced by Aspergillus and Penicillium species and occurs in a wide range of agricultural products. Detoxification of contaminated food is a challenging health issue. In the present paper we report the identification, characterization and crystal structure (at 2.2 Å) of a novel microbial ochratoxinase from Aspergillus niger. A putative amidase gene encoding a 480 amino acid polypeptide was cloned and homologously expressed in A. niger. The recombinant protein is N-terminally truncated, thermostable, has optimal activity at pH ~6 and 66°C, and is more efficient in ochratoxin A hydrolysis than carboxypeptidase A and Y, the two previously known enzymes capable of degrading this mycotoxin. The subunit of the homo-octameric enzyme folds into a two-domain structure characteristic of a metal dependent amidohydrolase, with a twisted TIM (triosephosphateisomerase)-barrel and a smaller β-sandwich domain. The active site contains an aspartate residue for acid-base catalysis, and a carboxylated lysine and four histidine residues for binding of a binuclear metal centre.
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Glucoamylase from a newly isolated Aspergillus niger FME: Detergent-Mediated production, purification, and characterization. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13765-012-3001-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Isolation of Aspergillus oryzae mutants for heterologous protein production from a double proteinase gene disruptant. Appl Microbiol Biotechnol 2009; 82:1105-14. [DOI: 10.1007/s00253-008-1851-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 12/26/2008] [Accepted: 12/29/2008] [Indexed: 11/26/2022]
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7
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Karnaukhova E, Ophir Y, Trinh L, Dalal N, Punt PJ, Golding B, Shiloach J. Expression of human alpha1-proteinase inhibitor in Aspergillus niger. Microb Cell Fact 2007; 6:34. [PMID: 17967194 PMCID: PMC2186354 DOI: 10.1186/1475-2859-6-34] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 10/29/2007] [Indexed: 11/30/2022] Open
Abstract
Background Human α1-proteinase inhibitor (α1-PI), also known as antitrypsin, is the most abundant serine protease inhibitor (serpin) in plasma. Its deficiency is associated with development of progressive, ultimately fatal emphysema. Currently in the United States, α1-PI is available for replacement therapy as an FDA licensed plasma-derived (pd) product. However, the plasma source itself is limited; moreover, even with efficient viral inactivation steps used in manufacture of plasma products, the risk of contamination from emerging viruses may still exist. Therefore, recombinant α1-PI (r-α1-PI) could provide an attractive alternative. Although r-α1-PI has been produced in several hosts, protein stability in vitro and rapid clearance from the circulation have been major issues, primarily due to absent or altered glycosylation. Results We have explored the possibility of expressing the gene for human α1-PI in the filamentous fungus Aspergillus niger (A. niger), a system reported to be capable of providing more "mammalian-like" glycosylation patterns to secretable proteins than commonly used yeast hosts. Our expression strategy was based on fusion of α1-PI with a strongly expressed, secreted leader protein (glucoamylase G2), separated by dibasic processing site (N-V-I-S-K-R) that provides in vivo cleavage. SDS-PAGE, Western blot, ELISA, and α1-PI activity assays enabled us to select the transformant(s) secreting a biologically active glycosylated r-α1-PI with yields of up to 12 mg/L. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis further confirmed that molecular mass of the r-α1-PI was similar to that of the pd-α1-PI. In vitro stability of the r-α1-PI from A. niger was tested in comparison with pd-α1-PI reference and non-glycosylated human r-α1-PI from E. coli. Conclusion We examined the suitability of the filamentous fungus A. niger for the expression of the human gene for α1-PI, a medium size glycoprotein of high therapeutic value. The heterologous expression of the human gene for α1-PI in A. niger was successfully achieved to produce the secreted mature human r-α1-PI in A. niger as a biologically active glycosylated protein with improved stability and with yields of up to 12 mg/L in shake-flask growth.
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Affiliation(s)
- Elena Karnaukhova
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda,Maryland, 20892 USA.
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van den Brink HJM, Petersen SG, Rahbek-Nielsen H, Hellmuth K, Harboe M. Increased production of chymosin by glycosylation. J Biotechnol 2006; 125:304-10. [PMID: 16621086 DOI: 10.1016/j.jbiotec.2006.02.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 02/22/2006] [Accepted: 02/27/2006] [Indexed: 10/24/2022]
Abstract
Filamentous fungi are well known in the industry as producers of large amounts of extracellular proteins. However, production levels of heterologous proteins are often disappointing low. In this paper it is shown that increasing glycosylation is a powerful strategy for increasing production levels of chymosin in filamentous fungi. Two different concepts based on glycosylation were tested. First, we improved a poorly used N-glycosylation site within the prochymosin molecule. The resulting highly glycosylated chymosin molecule was expressed in Aspergillus niger. It was shown that production of the glycosylated protein was much more efficient, giving a yield increase of more than 100% compared to production of the native chymosin molecule. In an alternative strategy the N-glycosylation site was located outside of the native chymosin molecule, on a linker separating prochymosin from its carrier molecule. Also in this case significantly increased production levels were obtained. This strategy might offer a powerful tool for increasing production levels of other heterologous proteins as well.
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Mander GJ, Wang H, Bodie E, Wagner J, Vienken K, Vinuesa C, Foster C, Leeder AC, Allen G, Hamill V, Janssen GG, Dunn-Coleman N, Karos M, Lemaire HG, Subkowski T, Bollschweiler C, Turner G, Nüsslein B, Fischer R. Use of laccase as a novel, versatile reporter system in filamentous fungi. Appl Environ Microbiol 2006; 72:5020-6. [PMID: 16820501 PMCID: PMC1489370 DOI: 10.1128/aem.00060-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 05/02/2006] [Indexed: 11/20/2022] Open
Abstract
Laccases are copper-containing enzymes which oxidize phenolic substrates and transfer the electrons to oxygen. Many filamentous fungi contain several laccase-encoding genes, but their biological roles are mostly not well understood. The main interest in laccases in biotechnology is their potential to be used to detoxify phenolic substances. We report here on a novel application of laccases as a reporter system in fungi. We purified a laccase enzyme from the ligno-cellulolytic ascomycete Stachybotrys chartarum. It oxidized the artificial substrate 2,2'-azino-di-(3-ethylbenzthiazolinsulfonate) (ABTS). The corresponding gene was isolated and expressed in Aspergillus nidulans, Aspergillus niger, and Trichoderma reesei. Heterologously expressed laccase activity was monitored in colorimetric enzyme assays and on agar plates with ABTS as a substrate. The use of laccase as a reporter was shown in a genetic screen for the isolation of improved T. reesei cellulase production strains. In addition to the laccase from S. charatarum, we tested the application of three laccases from A. nidulans (LccB, LccC, and LccD) as reporters. Whereas LccC oxidized ABTS (Km = 0.3 mM), LccD did not react with ABTS but with DMA/ADBP (3,5-dimethylaniline/4-amino-2,6-dibromophenol). LccB reacted with DMA/ADBP and showed weak activity with ABTS. The different catalytic properties of LccC and LccD allow simultaneous use of these two laccases as reporters in one fungal strain.
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Affiliation(s)
- Gerd J Mander
- Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
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10
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Kappeler SR, van den Brink HJM, Rahbek-Nielsen H, Farah Z, Puhan Z, Hansen EB, Johansen E. Characterization of recombinant camel chymosin reveals superior properties for the coagulation of bovine and camel milk. Biochem Biophys Res Commun 2006; 342:647-54. [PMID: 16488399 DOI: 10.1016/j.bbrc.2006.02.014] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Accepted: 02/06/2006] [Indexed: 11/16/2022]
Abstract
Enzymatic milk coagulation for cheese manufacturing involves the cleavage of the scissile bond in kappa-casein by an aspartic acid protease. Bovine chymosin is the preferred enzyme, combining a strong clotting activity with a low general proteolytic activity. In the present study, we report expression and enzymatic properties of recombinant camel chymosin expressed in Aspergillus niger. Camel chymosin was shown to have different characteristics than bovine chymosin. Camel chymosin exhibits a 70% higher clotting activity for bovine milk and has only 20% of the unspecific protease activity for bovine chymosin. This results in a sevenfold higher ratio of clotting to general proteolytic activity. The enzyme is more thermostable than bovine chymosin. Kinetic analysis showed that half-saturation is achieved with less than 50% of the substrate required for bovine chymosin and turnover rates are lower. While raw camel milk cannot be clotted with bovine chymosin, a high clotting activity was found with camel chymosin.
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Affiliation(s)
- Stefan R Kappeler
- Institute of Food Science, Swiss Federal Institute of Technology, CH-8092 Zurich, Switzerland
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11
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Sims AH, Gent ME, Lanthaler K, Dunn-Coleman NS, Oliver SG, Robson GD. Transcriptome analysis of recombinant protein secretion by Aspergillus nidulans and the unfolded-protein response in vivo. Appl Environ Microbiol 2005; 71:2737-47. [PMID: 15870366 PMCID: PMC1087583 DOI: 10.1128/aem.71.5.2737-2747.2005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Filamentous fungi have a high capacity for producing large amounts of secreted proteins, a property that has been exploited for commercial production of recombinant proteins. However, the secretory pathway, which is key to the production of extracellular proteins, is rather poorly characterized in filamentous fungi compared to yeast. We report the effects of recombinant protein secretion on gene expression levels in Aspergillus nidulans by directly comparing a bovine chymosin-producing strain with its parental wild-type strain in continuous culture by using expressed sequence tag microarrays. This approach demonstrated more subtle and specific changes in gene expression than those observed when mimicking the effects of protein overproduction by using a secretion blocker. The impact of overexpressing a secreted recombinant protein more closely resembles the unfolded-protein response in vivo.
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Affiliation(s)
- Andrew H Sims
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
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12
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Ward M, Lin C, Victoria DC, Fox BP, Fox JA, Wong DL, Meerman HJ, Pucci JP, Fong RB, Heng MH, Tsurushita N, Gieswein C, Park M, Wang H. Characterization of humanized antibodies secreted by Aspergillus niger. Appl Environ Microbiol 2004; 70:2567-76. [PMID: 15128505 PMCID: PMC404402 DOI: 10.1128/aem.70.5.2567-2576.2004] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two different humanized immunoglobulin G1(kappa) antibodies and an Fab' fragment were produced by Aspergillus niger. The antibodies were secreted into the culture supernatant. Both light and heavy chains were initially synthesized as fusion proteins with native glucoamylase. After antibody assembly, cleavage by A. niger KexB protease allowed the release of free antibody. Purification by hydrophobic charge induction chromatography proved effective at removing any antibody to which glucoamylase remained attached. Glycosylation at N297 in the Fc region of the heavy chain was observed, but this site was unoccupied on approximately 50% of the heavy chains. The glycan was of the high-mannose type, with some galactose present, and the size ranged from Hex(6)GlcNAc(2) to Hex(15)GlcNAc(2). An aglycosyl mutant form of antibody was also produced. No significant difference between the glycosylated antibody produced by Aspergillus and that produced by mammalian cell cultures was observed in tests for affinity, avidity, pharmacokinetics, or antibody-dependent cellular cytotoxicity function.
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Affiliation(s)
- Michael Ward
- Genencor International, Inc, Palo Alto, California 94304, USA.
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Saloheimo M, Wang H, Valkonen M, Vasara T, Huuskonen A, Riikonen M, Pakula T, Ward M, Penttilä M. Characterization of secretory genes ypt1/yptA and nsf1/nsfA from two filamentous fungi: induction of secretory pathway genes of Trichoderma reesei under secretion stress conditions. Appl Environ Microbiol 2004; 70:459-67. [PMID: 14711675 PMCID: PMC321314 DOI: 10.1128/aem.70.1.459-467.2004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two genes involved in protein secretion, encoding the Rab protein YPT1/YPTA and the general fusion factor NSFI/NSFA, were characterized from two filamentous fungi, Trichoderma reesei and Aspergillus niger var. awamori. The isolated genes showed a high level of conservation with their Saccharomyces cerevisiae and mammalian counterparts, and T. reesei ypt1 was shown to complement yeast Ypt1p depletion. The transcriptional regulation of the T. reesei ypt1, nsf1, and sar1 genes, involved in protein trafficking, was studied with mycelia treated with the folding inhibitor dithiothreitol (DTT) and with brefeldin A, which inhibits membrane traffic between the endoplasmic reticulum and Golgi complex. The well-known inducer of the yeast and T. reesei unfolded protein response (UPR), DTT, induced the nsf1 gene and the protein disulfide isomerase gene, pdi1, in both of the experiments, and sar1 mRNA increased in only one experiment under strong UPR induction. The ypt1 mRNA did not show a clear increase during DTT treatment. Brefeldin A strongly induced pdi1 and all of the intracellular trafficking genes studied. These results suggest the possibility that the whole secretory pathway of T. reesei could be induced at the transcriptional level by stress responses caused by protein accumulation in the secretory pathway.
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Affiliation(s)
- Markku Saloheimo
- VTT Biotechnology, Espoo, Finland. Genencor International, Inc., Palo Alto, California, USA.
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14
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Wang H, Entwistle J, Morlon E, Archer DB, Peberdy JF, Ward M, Jeenes DJ. Isolation and characterisation of a calnexin homologue, clxA, from Aspergillus niger. Mol Genet Genomics 2003; 268:684-91. [PMID: 12589443 DOI: 10.1007/s00438-002-0790-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2002] [Accepted: 11/27/2002] [Indexed: 10/25/2022]
Abstract
We describe the isolation of a gene (clxA) encoding calnexin from laboratory and industrial strains of Aspergillus niger. Calnexin is a chaperone, which specifically recognises monoglucosylated glycoproteins in the endoplasmic reticulum, and is thus an essential component of the process that assesses the folded state of nascent secreted glycoproteins. Manipulation of chaperones has previously been adopted in attempts to overcome some of the problems associated with the secretion of heterologous proteins from filamentous fungi. The A. niger clxA gene encodes a 562-residue protein with strong homology to the calnexin of Schizosaccharomyces pombe. The clxAgene product complements a S. pombe cnx1 mutant. Motifs associated with genes controlled via the Unfolded Protein Response (UPR) were identified by sequence homology in the promoter of clxA. Steady-state levels of clxA mRNA were elevated in a strain expressing bovine prochymosin fused to the catalytic domain of glucoamylase. The ORF is punctuated by four introns, and contains two sets of four repeated peptide motifs that are characteristic of the calnexin family, together with a putative membrane-spanning domain. Deletion studies indicate that clxA is not an essential gene in A. niger.
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MESH Headings
- Animals
- Aspergillus niger/genetics
- Aspergillus niger/metabolism
- Base Sequence
- Calnexin/genetics
- Calnexin/metabolism
- Cattle
- Chymosin/biosynthesis
- Chymosin/genetics
- DNA, Fungal/genetics
- Enzyme Precursors/biosynthesis
- Enzyme Precursors/genetics
- Fungal Proteins/genetics
- Fungal Proteins/metabolism
- Gene Deletion
- Gene Expression
- Genes, Fungal
- Genetic Complementation Test
- Glucan 1,4-alpha-Glucosidase/biosynthesis
- Glucan 1,4-alpha-Glucosidase/genetics
- Molecular Sequence Data
- Mutation
- Promoter Regions, Genetic
- RNA, Fungal/genetics
- RNA, Fungal/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/genetics
- Sequence Homology, Amino Acid
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Affiliation(s)
- H Wang
- Genencor International Inc., Palo Alto, CA 94304, USA
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15
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Saloheimo M, Paloheimo M, Hakola S, Pere J, Swanson B, Nyyssönen E, Bhatia A, Ward M, Penttilä M. Swollenin, a Trichoderma reesei protein with sequence similarity to the plant expansins, exhibits disruption activity on cellulosic materials. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:4202-11. [PMID: 12199698 DOI: 10.1046/j.1432-1033.2002.03095.x] [Citation(s) in RCA: 262] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Plant cell wall proteins called expansins are thought to disrupt hydrogen bonding between cell wall polysaccharides without hydrolyzing them. We describe here a novel gene with sequence similarity to plant expansins, isolated from the cellulolytic fungus Trichoderma reesei. The protein named swollenin has an N-terminal fungal type cellulose binding domain connected by a linker region to the expansin-like domain. The protein also contains regions similar to mammalian fibronectin type III repeats, found for the first time in a fungal protein. The swollenin gene is regulated in a largely similar manner as the T. reesei cellulase genes. The biological role of SWOI was studied by disrupting the swo1 gene from T. reesei. The disruption had no apparent effect on the growth rate on glucose or on different cellulosic carbon sources. Non-stringent Southern hybridization of Trichoderma genomic DNA with swo1 showed the presence of other swollenin-like genes, which could substitute for the loss of SWOI in the disruptant. The swollenin gene was expressed in yeast and Aspergillus niger var. awamori. Activity assays on cotton fibers and filter paper were performed with concentrated SWOI-containing yeast supernatant that disrupted the structure of the cotton fibers without detectable formation of reducing sugars. It also weakened filter paper as assayed by an extensometer. The SWOI protein was purified from A. niger var. awamori culture supernatant and used in an activity assay with Valonia cell walls. It disrupted the structure of the cell walls without producing detectable amounts of reducing sugars.
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16
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Cao QN, Stubbs M, Ngo KQ, Ward M, Cunningham A, Pai EF, Tu GC, Hofmann T. Penicillopepsin-JT2, a recombinant enzyme from Penicillium janthinellum and the contribution of a hydrogen bond in subsite S3 to k(cat). Protein Sci 2000; 9:991-1001. [PMID: 10850809 PMCID: PMC2144643 DOI: 10.1110/ps.9.5.991] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The nucleotide sequence of the gene (pepA) of a zymogen of an aspartic proteinase from Penicillium janthinellum with a 71% identity in the deduced amino acid sequence to penicillopepsin (which we propose to call penicillopepsin-JT1) has been determined. The gene consists of 60 codons for a putative leader sequence of 20 amino acid residues, a sequence of about 150 nucleotides that probably codes for an activation peptide and a sequence with two introns that codes for the active aspartic proteinase. This gene, inserted into the expression vector pGPT-pyrG1, was expressed in an aspartic proteinase-free strain of Aspergillus niger var. awamori in high yield as a glycosylated form of the active enzyme that we call penicillopepsin-JT2. After removal of the carbohydrate component with endoglycosidase H, its relative molecular mass is between 33,700 and 34,000. Its kinetic properties, especially the rate-enhancing effects of the presence of alanine residues in positions P3 and P2' of substrates, are similar to those of penicillopepsin-JT1, endothiapepsin, rhizopuspepsin, and pig pepsin. Earlier findings suggested that this rate-enhancing effect was due to a hydrogen bond between the -NH- of P3 and the hydrogen bond accepting oxygen of the side chain of the fourth amino acid residue C-terminal to Asp215. Thr219 of penicillopepsin-JT2 was mutated to Ser, Val, Gly, and Ala. Thr219Ser showed an increase in k(cat) when a P3 residue was present in the substrate, which was similar to that of the wild-type, whereas the mutants Thr219Val, Thr219Gly, and Thr219Ala showed no significant increase when a P3 residue was added. The results show that the putative hydrogen bond alone is responsible for the increase. We propose that by locking the -NH- of P3 to the enzyme, the scissile peptide bond between P1 and P1' becomes distorted toward a tetrahedral conformation and becomes more susceptible to nucleophilic attack by the catalytic apparatus without the need of a conformational change in the enzyme.
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Affiliation(s)
- Q N Cao
- Department of Biochemistry, University of Toronto, Ontario, Canada
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17
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Abstract
Enzymes from filamentous fungi are already widely exploited, but new applications for known enzymes and new enzymic activities continue to be found. In addition, enzymes from less amenable non-fungal sources require heterologous production and fungi are being used as the production hosts. In each case there is a need to improve production and to ensure quality of product. While conventional, mutagenesis-based, strain improvement methods will continue to be applied to enzyme production from filamentous fungi the application of recombinant DNA techniques is beginning to reveal important information on the molecular basis of fungal enzyme production and this knowledge is now being applied both in the laboratory and commercially. We review the current state of knowledge on the molecular basis of enzyme production by filamentous fungi. We focus on transcriptional and post-transcriptional regulation of protein production, the transit of proteins through the secretory pathway and the structure of the proteins produced including glycosylation.
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Affiliation(s)
- D B Archer
- Genetics and Microbiology Department, Institute of Food Research, Norwich, UK
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O'Herrin SM, Kulkarni S, Kenealy WR, Fechner JH, Sollinger H, Schneck JP, Burlingham WJ. Expression of human recombinant beta 2-microglobulin by Aspergillus nidulans and its activity. Hum Immunol 1996; 51:63-72. [PMID: 8960907 DOI: 10.1016/s0198-8859(96)00224-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The light chain of HLA class I protein (beta 2m) has been expressed in Aspergillus nidulans. The cDNA of beta 2m was modified using the polymerase chain reaction to include overlapping extensions for its subsequent fusion into an Aspergillus vector. This fusion resulted in beta 2m cDNA being flanked by the Aspergillus awamori glucoamylase promoter and the Aspergillus niger glucoamylase terminator. Expression of beta 2m was induced by the addition of starch to the culture medium. In preliminary mass culture trials, 177 micrograms/liter of f beta 2m were obtained in 60-liter fermentations. N-terminal sequencing of purified human beta 2m produced in fungi (f beta 2m) revealed that 28% of the purified protein was of proper sequence and 61% of the protein had an additional serine and lysine residue derived from the C-terminus of the fungal leader. Purified f beta 2m from culture supernatants appeared biochemically similar to beta 2m obtained from human urine (u beta 2m) as seen in immunoblot analysis. Functionally, f beta 2m effectively interacted as a subunit of class I MHC molecules. This was seen both in a sandwich ELISA for detecting properly folded HLA class I heavy chain and in assays showing cell-surface beta 2m exchange into the mouse class I MHC H-2Kd. In these experiments the biological activity of f beta 2m was indistinguishable from u beta 2m. The successful expression of biologically active beta 2m in A. nidulans suggests that fungal systems might be useful for the production of other active components of the HLA class I MHC complex.
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Affiliation(s)
- S M O'Herrin
- Department of Surgery, University of Wisconsin-Madison 53792, USA
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Withers JM, Wiebe MG, Robson GD, Osborne D, Turner G, Trinci AP. Stability of recombinant protein production byPenicillium chrysogenumin prolonged chemostat culture. FEMS Microbiol Lett 1995. [DOI: 10.1111/j.1574-6968.1995.tb07892.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Hoffmann T, Golz C, Schieder O. Foreign DNA sequences are received by a wild-type strain of Aspergillus niger after co-culture with transgenic higher plants. Curr Genet 1994; 27:70-6. [PMID: 7750149 DOI: 10.1007/bf00326581] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Different transgenic plants of Brassica napus, Brassica nigra, Datura innoxia and Vicia narbonensis expressing the hph gene under the control of the 35s promoter were co-cultivated with mycelial material of Aspergillus niger in microcosms under sterile conditions. A significantly higher number of hygromycin B-resistant colonies of re-isolated fungi was obtained if compared with co-cultures with non-transgenic plants. The hph gene and other foreign sequences could be detected in some of the resistant strains only for a short time after selection, indicating a rapid loss of foreign DNA. A more stable transgenic strain was obtained after co-culture with transgenic plants of D. innoxia including a high number of hph copies in their genome. DNA with detected pUC sequences was prepared to transform E. coli DH5 alpha. One of the recovered plasmids is shown to include pieces of the plant-transforming vector and a foreign sequence. The 35s-regulated expression of genes is studied in A. niger.
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MESH Headings
- Aspergillus niger/drug effects
- Aspergillus niger/genetics
- Aspergillus niger/growth & development
- Base Sequence
- Brassica/genetics
- Brassica/microbiology
- DNA, Fungal/genetics
- DNA, Plant/genetics
- DNA, Recombinant/genetics
- Datura stramonium/genetics
- Datura stramonium/microbiology
- Drug Resistance, Microbial/genetics
- Fabaceae/genetics
- Fabaceae/microbiology
- Genes, Bacterial
- Genes, Synthetic
- Hygromycin B/pharmacology
- Molecular Sequence Data
- Phosphotransferases (Alcohol Group Acceptor)/biosynthesis
- Phosphotransferases (Alcohol Group Acceptor)/genetics
- Plants, Genetically Modified
- Plants, Medicinal
- Plants, Toxic
- Promoter Regions, Genetic
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/genetics
- Transformation, Genetic
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Affiliation(s)
- T Hoffmann
- Institute of Applied Genetics, Free University Berlin, Germany
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Archer DB, Jeenes DJ, Mackenzie DA. Strategies for improving heterologous protein production from filamentous fungi. Antonie Van Leeuwenhoek 1994; 65:245-50. [PMID: 7847891 DOI: 10.1007/bf00871952] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Despite the naturally high capacity for protein secretion by many species of filamentous fungi, secreted yields of many heterologous proteins have been comparatively low. The strategies for yield improvement have included the use of strong homologous promoters, increased gene copy number, gene fusions with a gene encoding a naturally well-secreted protein, protease-deficient host strains and screening for high yields following random mutagenesis. Such approaches have been effective with some target heterologous proteins but not others. Approaches used in heterologous protein production from filamentous fungi are discussed and a perspective on emerging strategies is presented.
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Affiliation(s)
- D B Archer
- Institute of Food Research, Colney, Norwich, UK
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