A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein
Background Developing sustainable autotrophic cell factories depends heavily on the availability of robust and well-characterized biological parts. For cyanobacteria, these still lag behind the more advanced E. coli toolkit. In the course of previous protein expression experiments with cyanobacteria...
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PeerJ Inc.
2021-11-01
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| Online Access: | https://peerj.com/articles/12199.pdf |
| _version_ | 1797418421566046208 |
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| author | Mojca Juteršek Marko Dolinar |
| author_facet | Mojca Juteršek Marko Dolinar |
| author_sort | Mojca Juteršek |
| collection | DOAJ |
| description | Background Developing sustainable autotrophic cell factories depends heavily on the availability of robust and well-characterized biological parts. For cyanobacteria, these still lag behind the more advanced E. coli toolkit. In the course of previous protein expression experiments with cyanobacteria, we encountered inconveniences in working with currently available RSF1010-based shuttle plasmids, particularly due to their low biosafety and low yields of recombinant proteins. We also recognized some drawbacks of the commonly used fluorescent reporters, as quantification can be affected by the intrinsic fluorescence of cyanobacteria. To overcome these drawbacks, we envisioned a new chimeric vector and an alternative reporter that could be used in cyanobacterial synthetic biology and tested them in the model cyanobacterium Synechocystis sp. PCC 6803. Methods We designed the pMJc01 shuttle plasmid based on the broad host range RSFmob-I replicon. Standard cloning techniques were used for vector construction following the RFC10 synthetic biology standard. The behavior of pMJC01 was tested with selected regulatory elements in E. coli and Synechocystis sp. PCC 6803 for the biosynthesis of the established GFP reporter and of a new reporter protein, cystatin. Cystatin activity was assayed using papain as a cognate target. Results With the new vector we observed a significantly higher GFP expression in E. coli and Synechocystis sp. PCC 6803 compared to the commonly used RSF1010-based pPMQAK1. Cystatin, a cysteine protease inhibitor, was successfully expressed with the new vector in both E. coli and Synechocystis sp. PCC 6803. Its expression levels allowed quantification comparable to the standardly used fluorescent reporter GFPmut3b. An important advantage of the new vector is its improved biosafety due to the absence of plasmid regions encoding conjugative transfer components. The broadhost range vector pMJc01 could find application in synthetic biology and biotechnology of cyanobacteria due to its relatively small size, stability and ease of use. In addition, cystatin could be a useful reporter in all cell systems that do not contain papain-type proteases and inhibitors, such as cyanobacteria, and provides an alternative to fluorescent reporters or complements them. |
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| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-09T06:32:25Z |
| publishDate | 2021-11-01 |
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| spelling | doaj.art-d593f8359a2648baa8d43fb3446fcc1d2023-12-03T11:03:57ZengPeerJ Inc.PeerJ2167-83592021-11-019e1219910.7717/peerj.12199A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter proteinMojca Juteršek0Marko Dolinar1Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, SloveniaFaculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, SloveniaBackground Developing sustainable autotrophic cell factories depends heavily on the availability of robust and well-characterized biological parts. For cyanobacteria, these still lag behind the more advanced E. coli toolkit. In the course of previous protein expression experiments with cyanobacteria, we encountered inconveniences in working with currently available RSF1010-based shuttle plasmids, particularly due to their low biosafety and low yields of recombinant proteins. We also recognized some drawbacks of the commonly used fluorescent reporters, as quantification can be affected by the intrinsic fluorescence of cyanobacteria. To overcome these drawbacks, we envisioned a new chimeric vector and an alternative reporter that could be used in cyanobacterial synthetic biology and tested them in the model cyanobacterium Synechocystis sp. PCC 6803. Methods We designed the pMJc01 shuttle plasmid based on the broad host range RSFmob-I replicon. Standard cloning techniques were used for vector construction following the RFC10 synthetic biology standard. The behavior of pMJC01 was tested with selected regulatory elements in E. coli and Synechocystis sp. PCC 6803 for the biosynthesis of the established GFP reporter and of a new reporter protein, cystatin. Cystatin activity was assayed using papain as a cognate target. Results With the new vector we observed a significantly higher GFP expression in E. coli and Synechocystis sp. PCC 6803 compared to the commonly used RSF1010-based pPMQAK1. Cystatin, a cysteine protease inhibitor, was successfully expressed with the new vector in both E. coli and Synechocystis sp. PCC 6803. Its expression levels allowed quantification comparable to the standardly used fluorescent reporter GFPmut3b. An important advantage of the new vector is its improved biosafety due to the absence of plasmid regions encoding conjugative transfer components. The broadhost range vector pMJc01 could find application in synthetic biology and biotechnology of cyanobacteria due to its relatively small size, stability and ease of use. In addition, cystatin could be a useful reporter in all cell systems that do not contain papain-type proteases and inhibitors, such as cyanobacteria, and provides an alternative to fluorescent reporters or complements them.https://peerj.com/articles/12199.pdfCyanobacteriaSynechocystis sp. PCC 6803Reporter proteinCystatinBiosafetySynthetic biology |
| spellingShingle | Mojca Juteršek Marko Dolinar A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein PeerJ Cyanobacteria Synechocystis sp. PCC 6803 Reporter protein Cystatin Biosafety Synthetic biology |
| title | A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein |
| title_full | A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein |
| title_fullStr | A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein |
| title_full_unstemmed | A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein |
| title_short | A chimeric vector for dual use in cyanobacteria and Escherichia coli, tested with cystatin, a nonfluorescent reporter protein |
| title_sort | chimeric vector for dual use in cyanobacteria and escherichia coli tested with cystatin a nonfluorescent reporter protein |
| topic | Cyanobacteria Synechocystis sp. PCC 6803 Reporter protein Cystatin Biosafety Synthetic biology |
| url | https://peerj.com/articles/12199.pdf |
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