1
|
Connor A, Zha RH, Koffas M. Production and secretion of recombinant spider silk in Bacillus megaterium. Microb Cell Fact 2024; 23:35. [PMID: 38279170 PMCID: PMC10821235 DOI: 10.1186/s12934-024-02304-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/12/2024] [Indexed: 01/28/2024] Open
Abstract
BACKGROUND Silk proteins have emerged as versatile biomaterials with unique chemical and physical properties, making them appealing for various applications. Among them, spider silk, known for its exceptional mechanical strength, has attracted considerable attention. Recombinant production of spider silk represents the most promising route towards its scaled production; however, challenges persist within the upstream optimization of host organisms, including toxicity and low yields. The high cost of downstream cell lysis and protein purification is an additional barrier preventing the widespread production and use of spider silk proteins. Gram-positive bacteria represent an attractive, but underexplored, microbial chassis that may enable a reduction in the cost and difficulty of recombinant silk production through attributes that include, superior secretory capabilities, frequent GRAS status, and previously established use in industry. RESULTS In this study, we explore the potential of gram-positive hosts by engineering the first production and secretion of recombinant spider silk in the Bacillus genus. Using an industrially relevant B. megaterium host, it was found that the Sec secretion pathway enables secretory production of silk, however, the choice of signal sequence plays a vital role in successful secretion. Attempts at increasing secreted titers revealed that multiple translation initiation sites in tandem do not significantly impact silk production levels, contrary to previous findings for other gram-positive hosts and recombinant proteins. Notwithstanding, targeted amino acid supplementation in minimal media was found to increase production by 135% relative to both rich media and unaltered minimal media, yielding secretory titers of approximately 100 mg/L in flask cultures. CONCLUSION It is hypothesized that the supplementation strategy addressed metabolic bottlenecks, specifically depletion of ATP and NADPH within the central metabolism, that were previously observed for an E. coli host producing the same recombinant silk construct. Furthermore, this study supports the hypothesis that secretion mitigates the toxicity of the produced silk protein on the host organism and enhances host performance in glucose-based minimal media. While promising, future research is warranted to understand metabolic changes more precisely in the Bacillus host system in response to silk production, optimize signal sequences and promoter strengths, investigate the mechanisms behind the effect of tandem translation initiation sites, and evaluate the performance of this system within a bioreactor.
Collapse
Affiliation(s)
- Alexander Connor
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - R Helen Zha
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| | - Mattheos Koffas
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| |
Collapse
|
2
|
Boock JT, Freedman AJE, Tompsett GA, Muse SK, Allen AJ, Jackson LA, Castro-Dominguez B, Timko MT, Prather KLJ, Thompson JR. Engineered microbial biofuel production and recovery under supercritical carbon dioxide. Nat Commun 2019; 10:587. [PMID: 30718495 PMCID: PMC6361901 DOI: 10.1038/s41467-019-08486-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 01/11/2019] [Indexed: 12/16/2022] Open
Abstract
Culture contamination, end-product toxicity, and energy efficient product recovery are long-standing bioprocess challenges. To solve these problems, we propose a high-pressure fermentation strategy, coupled with in situ extraction using the abundant and renewable solvent supercritical carbon dioxide (scCO2), which is also known for its broad microbial lethality. Towards this goal, we report the domestication and engineering of a scCO2-tolerant strain of Bacillus megaterium, previously isolated from formation waters from the McElmo Dome CO2 field, to produce branched alcohols that have potential use as biofuels. After establishing induced-expression under scCO2, isobutanol production from 2-ketoisovalerate is observed with greater than 40% yield with co-produced isopentanol. Finally, we present a process model to compare the energy required for our process to other in situ extraction methods, such as gas stripping, finding scCO2 extraction to be potentially competitive, if not superior. End-product toxicity, culture contamination, and energy efficient product recovery are long-standing issues in bioprocessing. Here, the authors address these problems using a fermentation strategy that combines microbial production of branched alcohols with supercritical carbon dioxide extraction.
Collapse
Affiliation(s)
- Jason T Boock
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, OH, 45056, USA
| | - Adam J E Freedman
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Geoffrey A Tompsett
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Sarah K Muse
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Audrey J Allen
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Luke A Jackson
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Bernardo Castro-Dominguez
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA.,Department of Chemical Engineering, University of Bath, Bath, BA2 7AY, UK
| | - Michael T Timko
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Kristala L J Prather
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Janelle R Thompson
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| |
Collapse
|
3
|
Li Y, Jin K, Zhang L, Ding Z, Gu Z, Shi G. Development of an Inducible Secretory Expression System in Bacillus licheniformis Based on an Engineered Xylose Operon. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:9456-9464. [PMID: 30129762 DOI: 10.1021/acs.jafc.8b02857] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The xylose operon can be an efficient biological component for regulatory expression uses in Bacillus licheniformis. However, its characteristic susceptibility to carbon catabolite repression (CCR) makes its application inconvenient. In this study, plasmids harboring the wild-type operons from three Bacillus species were constructed and introduced into B. licheniformis. These plasmids ensured secretory expression of maltogenic α-amylase (BLMA) in B. licheniformis under strict regulation. The glucose-mediated CCR was then alleviated by engineering the xylose operon of the expression system. Evidence showed that mutations in the highly conserved nucleotides of the identified catabolite responsive element (cre) consensus sequence prevented association of the regulator CcpA with DNA, thus resulting in an increase in BLMA activity of up to 12-fold. Furthermore, features of this engineered system for inducible expression were investigated. Induction in mid-log phase using 10 g/L xylose at 37 °C was found to be beneficial for promoting the accumulation of recombinant product, and the maximum yield of BlmMA reached 715.4 U/mL. This study contributes to the industrial application of the generally recognized as safe (GRAS) workhorse B. licheniformis.
Collapse
Affiliation(s)
- Youran Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education , Jiangnan University , Wuxi 214122 , P. R. China
- National Engineering Laboratory for Cereal Fermentation Technology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu Province 214122 , P. R. China
| | - Ke Jin
- Key Laboratory of Industrial Biotechnology, Ministry of Education , Jiangnan University , Wuxi 214122 , P. R. China
- National Engineering Laboratory for Cereal Fermentation Technology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu Province 214122 , P. R. China
| | - Liang Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education , Jiangnan University , Wuxi 214122 , P. R. China
- National Engineering Laboratory for Cereal Fermentation Technology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu Province 214122 , P. R. China
| | - Zhongyang Ding
- Key Laboratory of Industrial Biotechnology, Ministry of Education , Jiangnan University , Wuxi 214122 , P. R. China
- National Engineering Laboratory for Cereal Fermentation Technology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu Province 214122 , P. R. China
| | - Zhenghua Gu
- Key Laboratory of Industrial Biotechnology, Ministry of Education , Jiangnan University , Wuxi 214122 , P. R. China
- National Engineering Laboratory for Cereal Fermentation Technology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu Province 214122 , P. R. China
| | - Guiyang Shi
- Key Laboratory of Industrial Biotechnology, Ministry of Education , Jiangnan University , Wuxi 214122 , P. R. China
- National Engineering Laboratory for Cereal Fermentation Technology , Jiangnan University , 1800 Lihu Avenue , Wuxi , Jiangsu Province 214122 , P. R. China
| |
Collapse
|
4
|
Irla M, Heggeset TMB, Nærdal I, Paul L, Haugen T, Le SB, Brautaset T, Wendisch VF. Genome-Based Genetic Tool Development for Bacillus methanolicus: Theta- and Rolling Circle-Replicating Plasmids for Inducible Gene Expression and Application to Methanol-Based Cadaverine Production. Front Microbiol 2016; 7:1481. [PMID: 27713731 PMCID: PMC5031790 DOI: 10.3389/fmicb.2016.01481] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/06/2016] [Indexed: 11/30/2022] Open
Abstract
Bacillus methanolicus is a thermophilic methylotroph able to overproduce amino acids from methanol, a substrate not used for human or animal nutrition. Based on our previous RNA-seq analysis a mannitol inducible promoter and a putative mannitol activator gene mtlR were identified. The mannitol inducible promoter was applied for controlled gene expression using fluorescent reporter proteins and a flow cytometry analysis, and improved by changing the -35 promoter region and by co-expression of the mtlR regulator gene. For independent complementary gene expression control, the heterologous xylose-inducible system from B. megaterium was employed and a two-plasmid gene expression system was developed. Four different replicons for expression vectors were compared with respect to their copy number and stability. As an application example, methanol-based production of cadaverine was shown to be improved from 6.5 to 10.2 g/L when a heterologous lysine decarboxylase gene cadA was expressed from a theta-replicating rather than a rolling-circle replicating vector. The current work on inducible promoter systems and compatible theta- or rolling circle-replicating vectors is an important extension of the poorly developed B. methanolicus genetic toolbox, valuable for genetic engineering and further exploration of this bacterium.
Collapse
Affiliation(s)
- Marta Irla
- Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University Bielefeld, Germany
| | - Tonje M B Heggeset
- SINTEF Materials and Chemistry, Department of Biotechnology and Nanomedicine Trondheim, Norway
| | - Ingemar Nærdal
- SINTEF Materials and Chemistry, Department of Biotechnology and Nanomedicine Trondheim, Norway
| | - Lidia Paul
- Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University Bielefeld, Germany
| | - Tone Haugen
- SINTEF Materials and Chemistry, Department of Biotechnology and Nanomedicine Trondheim, Norway
| | - Simone B Le
- SINTEF Materials and Chemistry, Department of Biotechnology and Nanomedicine Trondheim, Norway
| | - Trygve Brautaset
- SINTEF Materials and Chemistry, Department of Biotechnology and NanomedicineTrondheim, Norway; Department of Biotechnology, Norwegian University of Science and TechnologyTrondheim, Norway
| | - Volker F Wendisch
- Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University Bielefeld, Germany
| |
Collapse
|
5
|
Murayama S, Ishikawa S, Chumsakul O, Ogasawara N, Oshima T. The Role of α-CTD in the Genome-Wide Transcriptional Regulation of the Bacillus subtilis Cells. PLoS One 2015; 10:e0131588. [PMID: 26154296 PMCID: PMC4495994 DOI: 10.1371/journal.pone.0131588] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 06/02/2015] [Indexed: 11/22/2022] Open
Abstract
The amino acid sequence of the RNA polymerase (RNAP) α-subunit is well conserved throughout the Eubacteria. Its C-terminal domain (α-CTD) is important for the transcriptional regulation of specific promoters in both Escherichia coli and Bacillus subtilis, through interactions with transcription factors and/or a DNA element called the "UP element". However, there is only limited information regarding the α-CTD regulated genes in B. subtilis and the importance of this subunit in the transcriptional regulation of B. subtilis. Here, we established strains and the growth conditions in which the α-subunit of RNAP was replaced with a C-terminally truncated version. Transcriptomic and ChAP-chip analyses revealed that α-CTD deficiency reduced the transcription and RNAP binding of genes related to the utilization of secondary carbon sources, transition state responses, and ribosome synthesis. In E. coli, it is known that α-CTD also contributes to the expression of genes related to the utilization of secondary carbon sources and ribosome synthesis. Our results suggest that the biological importance of α-CTD is conserved in B. subtilis and E. coli, but that its specific roles have diversified between these two bacteria.
Collapse
Affiliation(s)
- Satohiko Murayama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Shu Ishikawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Onuma Chumsakul
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Naotake Ogasawara
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916–5, Takayama, Ikoma, Nara 630–0192, Japan
| |
Collapse
|
6
|
Identification and inactivation of pleiotropic regulator CcpA to eliminate glucose repression of xylose utilization in Clostridium acetobutylicum. Metab Eng 2010; 12:446-54. [DOI: 10.1016/j.ymben.2010.05.002] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 05/05/2010] [Accepted: 05/10/2010] [Indexed: 11/21/2022]
|
7
|
Carbon catabolite repression in Bacillus subtilis: quantitative analysis of repression exerted by different carbon sources. J Bacteriol 2008; 190:7275-84. [PMID: 18757537 DOI: 10.1128/jb.00848-08] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In many bacteria glucose is the preferred carbon source and represses the utilization of secondary substrates. In Bacillus subtilis, this carbon catabolite repression (CCR) is achieved by the global transcription regulator CcpA, whose activity is triggered by the availability of its phosphorylated cofactors, HPr(Ser46-P) and Crh(Ser46-P). Phosphorylation of these proteins is catalyzed by the metabolite-controlled kinase HPrK/P. Recent studies have focused on glucose as a repressing substrate. Here, we show that many carbohydrates cause CCR. The substrates form a hierarchy in their ability to exert repression via the CcpA-mediated CCR pathway. Of the two cofactors, HPr is sufficient for complete CCR. In contrast, Crh cannot substitute for HPr on substrates that cause a strong repression. Determination of the phosphorylation state of HPr in vivo revealed a correlation between the strength of repression and the degree of phosphorylation of HPr at Ser46. Sugars transported by the phosphotransferase system (PTS) cause the strongest repression. However, the phosphorylation state of HPr at its His15 residue and PTS transport activity have no impact on the global CCR mechanism, which is a major difference compared to the mechanism operative in Escherichia coli. Our data suggest that the hierarchy in CCR exerted by the different substrates is exclusively determined by the activity of HPrK/P.
Collapse
|
8
|
Regulation of D-xylose metabolism in Caulobacter crescentus by a LacI-type repressor. J Bacteriol 2007; 189:8828-34. [PMID: 17933895 DOI: 10.1128/jb.01342-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In the oligotrophic freshwater bacterium Caulobacter crescentus, D-xylose induces expression of over 50 genes, including the xyl operon, which encodes key enzymes for xylose metabolism. The promoter (P(xylX)) controlling expression of the xyl operon is widely used as a tool for inducible heterologous gene expression in C. crescentus. We show here that P(xylX) and at least one other promoter in the xylose regulon (P(xylE)) are controlled by the CC3065 (xylR) gene product, a LacI-type repressor. Electrophoretic gel mobility shift assays showed that operator binding by XylR is greatly reduced in the presence of D-xylose. The data support the hypothesis that there is a simple regulatory mechanism in which XylR obstructs xylose-inducible promoters in the absence of the sugar; the repressor is induced to release DNA upon binding D-xylose, thereby freeing the promoter for productive interaction with RNA polymerase. XylR also has an effect on glucose metabolism, as xylR mutants exhibit reduced expression of the Entner-Doudoroff operon and their ability to utilize glucose as a sole carbon and energy source is compromised.
Collapse
|
9
|
Erlandson KA, Park JH, Kao HH, Basaran P, Brydges S, Batt CA. Dissolution of xylose metabolism in Lactococcus lactis. Appl Environ Microbiol 2000; 66:3974-80. [PMID: 10966417 PMCID: PMC92247 DOI: 10.1128/aem.66.9.3974-3980.2000] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Xylose metabolism, a variable phenotype in strains of Lactococcus lactis, was studied and evidence was obtained for the accumulation of mutations that inactivate the xyl operon. The xylose metabolism operon (xylRAB) was sequenced from three strains of lactococci. Fragments of 4.2, 4.2, and 5.4 kb that included the xyl locus were sequenced from L. lactis subsp. lactis B-4449 (formerly Lactobacillus xylosus), L. lactis subsp. lactis IO-1, and L. lactis subsp. lactis 210, respectively. The two environmental isolates, L. lactis B-4449 and L. lactis IO-1, produce active xylose isomerases and xylulokinases and can metabolize xylose. L. lactis 210, a dairy starter culture strain, has neither xylose isomerase nor xylulokinase activity and is Xyl(-). Xylose isomerase and xylulokinase activities are induced by xylose and repressed by glucose in the two Xyl(+) strains. Sequence comparisons revealed a number of point mutations in the xylA, xylB, and xylR genes in L. lactis 210, IO-1, and B-4449. None of these mutations, with the exception of a premature stop codon in xylB, are obviously lethal, since they lie outside of regions recognized as critical for activity. Nevertheless, either cumulatively or because of indirect affects on the structures of catalytic sites, these mutations render some strains of L. lactis unable to metabolize xylose.
Collapse
Affiliation(s)
- K A Erlandson
- Department of Food Science, Cornell University, Ithaca, New York 14853, USA
| | | | | | | | | | | |
Collapse
|
10
|
Küster E, Hilbich T, Dahl MK, Hillen W. Mutations in catabolite control protein CcpA separating growth effects from catabolite repression. J Bacteriol 1999; 181:4125-8. [PMID: 10383986 PMCID: PMC93908 DOI: 10.1128/jb.181.13.4125-4128.1999] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Carbon catabolite repression in Bacillus megaterium is mediated by the transcriptional regulator CcpA. A chromosomal deletion of ccpA eliminates catabolite repression and reduces the growth rate on glucose. We describe four single-amino-acid mutations in CcpA which separate the growth effect from catabolite repression, suggesting distinct regulatory pathways for these phenotypes.
Collapse
Affiliation(s)
- E Küster
- Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik der Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Federal Republic of Germany
| | | | | | | |
Collapse
|
11
|
Takeda Y, Takase K, Yamato I, Abe K. Sequencing and characterization of the xyl operon of a gram-positive bacterium, Tetragenococcus halophila. Appl Environ Microbiol 1998; 64:2513-9. [PMID: 9647823 PMCID: PMC106419 DOI: 10.1128/aem.64.7.2513-2519.1998] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The xyl operon of a gram-positive bacterium, Tetragenococcus halophila (previously called Pediococcus halophilus), was cloned and sequenced. The DNA was about 7.7 kb long and contained genes for a ribose binding protein and part of a ribose transporter, xylR (a putative regulatory gene), and the xyl operon, along with its regulatory region and transcription termination signal, in this order. The DNA was AT rich, the GC content being 35.8%, consistent with the GC content of this gram-positive bacterium. The xyl operon consisted of three genes, xylA, encoding a xylose isomerase, xylB, encoding a xylulose kinase, and xylE, encoding a xylose transporter, with predicted molecular weights of 49,400, 56,400, and 51,600, respectively. The deduced amino acid sequences of the XylR, XylA, XylB, and XylE proteins were similar to those of the corresponding proteins in other gram-positive and -negative bacteria, the similarities being 37 to 64%. Each polypeptide of XylB and XylE was expressed functionally in Escherichia coli. XylE transported D-xylose in a sodium ion-dependent manner, suggesting that it is the first described xylose/Na+ symporter. The XylR protein contained a consensus sequence for binding catabolites of glucose, such as glucose-6-phosphate, which has been discovered in glucose and fructose kinases in bacteria. Correspondingly, the regulatory region of this operon contained a putative binding site of XylR with a palindromic structure. Furthermore, it contained a consensus sequence, CRE (catabolite-responsive element), for binding CcpA (catabolite control protein A). We speculate that the transcriptional regulation of this operon resembles the regulation of catabolite-repressible operons such as the amy, lev, xyl, and gnt operons in various gram-positive bacteria. We discuss the significance of the regulation of gene expression of this operon in T. halophila.
Collapse
Affiliation(s)
- Y Takeda
- Department of Biological Science and Technology, Science University of Tokyo, Japan
| | | | | | | |
Collapse
|
12
|
Simpson CL, Russell RR. Identification of a homolog of CcpA catabolite repressor protein in Streptococcus mutans. Infect Immun 1998; 66:2085-92. [PMID: 9573093 PMCID: PMC108167 DOI: 10.1128/iai.66.5.2085-2092.1998] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A locus containing a gene with homology to ccpA of other bacteria has been cloned from Streptococcus mutans LT11, sequenced, and named regM. Upstream of the regM gene, on the opposite strand, is a gene encoding an X-Pro dipeptidase, pepQ. A 14-bp palindromic sequence with homology to the consensus catabolite-responsive element sequence lay in the promoter region between the two genes. To study the function of regM, the gene was inactivated by insertion of an antibiotic resistance marker. Diauxic growth of S. mutans on a number of sugars in the presence of glucose was not affected by disruption of regM. The loss of RegM increased glucose repression of alpha-galactosidase, mannitol-1-P dehydrogenase, and P-beta-galactosidase activities. These results suggest that while RegM can affect catabolite repression in S. mutans, it does not conform to the model proposed for CcpA in Bacillus subtilis.
Collapse
Affiliation(s)
- C L Simpson
- Department of Oral Biology, The Dental School, University of Newcastle upon Tyne, United Kingdom
| | | |
Collapse
|
13
|
Moch C, Schrögel O, Allmansberger R. The sigmaD-dependent transcription of the ywcG gene from Bacillus subtilis is dependent on an excess of glucose and glutamate. Mol Microbiol 1998; 27:889-98. [PMID: 9535080 DOI: 10.1046/j.1365-2958.1998.00734.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We investigated the function and transcriptional regulation of ywcG. The protein is essential for Bacillus subtilis. Biochemical characterization of the protein revealed that it is an FMN-containing NADPH oxidase. ywcG is transcribed throughout the whole life cycle of B. subtilis. The start point of transcription is preceded by potential promoter sequences for sigmaA, sigmaB and sigmaD. A boost in transcription occurs at the beginning of stationary phase in complex media containing glutamate and glucose. The induction of transcription at the beginning of stationary phase needs the activity of a different alternative sigma-factor sigmaD. ywcG is, therefore, the first gene with a putative role in energy metabolism from B. subtilis that is transcribed in a sigmaD-dependent fashion, but its regulation is unique and the reverse of that described for all other sigmaD-dependent genes.
Collapse
Affiliation(s)
- C Moch
- Lehrstuhl für Mikrobiologie, Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | | |
Collapse
|
14
|
Gösseringer R, Küster E, Galinier A, Deutscher J, Hillen W. Cooperative and non-cooperative DNA binding modes of catabolite control protein CcpA from Bacillus megaterium result from sensing two different signals. J Mol Biol 1997; 266:665-76. [PMID: 9102460 DOI: 10.1006/jmbi.1996.0820] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Carbon catabolite repression (CCR) of several operons in Bacillus subtilis and Bacillus megaterium is mediated by the cis-acting cre sequence and trans-acting catabolite control protein (CcpA). We describe purification of CcpA from B. megaterium and its interaction with regulatory sequences from the xyl operon. Specific interaction of CcpA with cre as scored by DNase I footprints at concentrations similar to the in vivo situation requires the presence of effectors. We have found two molecular effectors for CcpA activity, which lead to different recognition modes of DNA. The heat-stable phosphotransfer protein HPr from the PTS sugar uptake system triggers non-cooperative binding of CcpA to cre when phosphorylated at Ser46 (HPr-Ser46-P). Glucose 6-phosphate (Glc-6-P) triggers cooperative binding of CcpA to cre and two auxiliary cre* sites, one of which overlaps the -35 box of the xyl promoter. Binding to cre* depends on the presence of the functional cre sequence. A mutation in cre abolishes carbon catabolite repression in vivo and binding of CcpA to cre and cre* in vitro, indicating looping of the intervening DNA. The two triggers are not simultaneously active. The acidity of the buffer determines which of them activates CcpA when both are present in vitro. Glc-6-P is preferred at pH values below 5.4, and HPr-Ser46-P is preferred at neutral pH. The Ccpa dimers present at neutral pH form tetramers and higher oligomers at pH 4.6, explaining cooperativity of binding to DNA. CcpA is the first member of the LacI/GalR family of regulators, for which oligomerization without the leucine zipper at the C terminus is demonstrated.
Collapse
Affiliation(s)
- R Gösseringer
- Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik, Friedrich-Alexander Universität Erlangen-Nürnberg, FRG
| | | | | | | | | |
Collapse
|
15
|
Meisenzahl AC, Shapiro L, Jenal U. Isolation and characterization of a xylose-dependent promoter from Caulobacter crescentus. J Bacteriol 1997; 179:592-600. [PMID: 9006009 PMCID: PMC178736 DOI: 10.1128/jb.179.3.592-600.1997] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
An inducible promoter is a useful tool for the controlled expression of a given gene. Accordingly, we identified, cloned, and sequenced a chromosomal locus, xylX, from Caulobacter crescentus which is required for growth on xylose as the sole carbon source and showed that transcription from a single site is dependent on the presence of xylose in the growth medium. P(xylX) promoter activity was determined as a function of the composition of the growth medium both in single copy and on a plasmid using different reporter genes. One hundred micromolar exogenously added xylose was required for maximal induction of P(xylX) in a strain that is unable to metabolize xylose. P(xylX) activity was induced immediately after the addition of xylose and repressed almost completely when xylose was removed from the growth medium. In addition to the strong transcriptional control, the expression of xylX is also regulated on the translational level.
Collapse
Affiliation(s)
- A C Meisenzahl
- Department of Developmental Biology, Stanford University School of Medicine, California 94305-5427, USA
| | | | | |
Collapse
|
16
|
Commentary by M.H. Saier, Jr.:. Res Microbiol 1996. [DOI: 10.1016/s0923-2508(96)90152-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|