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Hao W, Cui W, Liu Z, Suo F, Wu Y, Han L, Zhou Z. A New-Generation Base Editor with an Expanded Editing Window for Microbial Cell Evolution In Vivo Based on CRISPR‒Cas12b Engineering. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309767. [PMID: 38602436 PMCID: PMC11165516 DOI: 10.1002/advs.202309767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/07/2024] [Indexed: 04/12/2024]
Abstract
Base editors (BEs) are widely used as revolutionary genome manipulation tools for cell evolution. To screen the targeted individuals, it is often necessary to expand the editing window to ensure highly diverse variant library. However, current BEs suffer from a limited editing window of 5-6 bases, corresponding to only 2-3 amino acids. Here, by engineering the CRISPR‒Cas12b, the study develops dCas12b-based CRISPRi system, which can efficiently repress gene expression by blocking the initiation and elongation of gene transcription. Further, based on dCas12b, a new-generation of BEs with an expanded editing window is established, covering the entire protospacer or more. The expanded editing window results from the smaller steric hindrance compared with other Cas proteins. The universality of the new BE is successfully validated in Bacillus subtilis and Escherichia coli. As a proof of concept, a spectinomycin-resistant E. coli strain (BL21) and a 6.49-fold increased protein secretion efficiency in E. coli JM109 are successfully obtained by using the new BE. The study, by tremendously expanding the editing window of BEs, increased the capacity of the variant library exponentially, greatly increasing the screening efficiency for microbial cell evolution.
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Affiliation(s)
- Wenliang Hao
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
| | - Wenjing Cui
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
| | - Zhongmei Liu
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
| | - Feiya Suo
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
| | - Yaokang Wu
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
- Science Center for Future FoodsJiangnan UniversityWuxi214122China
| | - Laichuang Han
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
| | - Zhemin Zhou
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of BiotechnologyJiangnan University1800 Lihu AvenueWuxi214122China
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Osgerby A, Overton TW. Approaches for high-throughput quantification of periplasmic recombinant proteins. N Biotechnol 2023; 77:149-160. [PMID: 37708933 DOI: 10.1016/j.nbt.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 09/01/2023] [Accepted: 09/11/2023] [Indexed: 09/16/2023]
Abstract
The Gram-negative periplasm is a convenient location for the accumulation of many recombinant proteins including biopharmaceutical products. It is the site of disulphide bond formation, required by some proteins (such as antibody fragments) for correct folding and function. It also permits simpler protein release and downstream processing than cytoplasmic accumulation. As such, targeting of recombinant proteins to the E. coli periplasm is a key strategy in biologic manufacture. However, expression and translocation of each recombinant protein requires optimisation including selection of the best signal peptide and growth and production conditions. Traditional methods require separation and analysis of protein compositions of periplasmic and cytoplasmic fractions, a time- and labour-intensive method that is difficult to parallelise. Therefore, approaches for high throughput quantification of periplasmic protein accumulation offer advantages in rapid process development.
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Affiliation(s)
- Alexander Osgerby
- School of Chemical Engineering and Institute of Microbiology and Infection, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Tim W Overton
- School of Chemical Engineering and Institute of Microbiology and Infection, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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Yu X, Li S, Feng H, Liao X, Xing XH, Bai Z, Liu X, Zhang C. CRISPRi-microfluidics screening enables genome-scale target identification for high-titer protein production and secretion. Metab Eng 2023; 75:192-204. [PMID: 36572334 DOI: 10.1016/j.ymben.2022.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 12/16/2022] [Accepted: 12/17/2022] [Indexed: 12/25/2022]
Abstract
Genome-scale target identification promises to guide microbial cell factory engineering for higher-titer production of biomolecules such as recombinant proteins (r-protein), but challenges remain due to the need not only for comprehensive genotypic perturbation but also in conjunction with high-throughput phenotypic screening strategies. Here, we developed a CRISPRi-microfluidics screening platform to systematically identify crucial gene targets that can be engineered to enhance r-protein secretion in Corynebacterium glutamicum. We created a CRISPR interference (CRISPRi) library containing 46,549 single-guide RNAs, where we aimed to unbiasedly target all genes for repression. Meanwhile, we developed a highly efficient droplet-based microfluidics system integrating the FlAsH-tetracysteine assay that enables screening of millions of strains to identify potential knockdowns conducive to nanobody VHH secretion. Among our highest-ranking candidates are a slew of previously unknown targets involved in transmembrane transport, amino-acid metabolism and redox regulation. Guided by these findings, we eventually constructed a hyperproducer for multiple proteins via combinatorial engineering of redox-response transcription factors. As the near-universal applicability of CRISPRi technology and the FlAsH-based screening platform, this procedure might be expanded to include a varied variety of microbial species and recombinant proteins.
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Affiliation(s)
- Xinyu Yu
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Shuang Li
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Huibao Feng
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Xihao Liao
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Xin-Hui Xing
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China; Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, 518055, China
| | - Zhonghu Bai
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Xiuxia Liu
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China.
| | - Chong Zhang
- MOE Key Laboratory for Industrial Biocatalysis, Institute of Biochemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, 100084, China.
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Engineering Ag43 Signal Peptides with Bacterial Display and Selection. Methods Protoc 2022; 6:mps6010001. [PMID: 36648950 PMCID: PMC9844295 DOI: 10.3390/mps6010001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/13/2022] [Accepted: 12/16/2022] [Indexed: 12/28/2022] Open
Abstract
Protein display, secretion, and export in prokaryotes are essential for utilizing microbial systems as engineered living materials, medicines, biocatalysts, and protein factories. To select for improved signal peptides for Escherichia coli protein display, we utilized error-prone polymerase chain reaction (epPCR) coupled with single-cell sorting and microplate titer to generate, select, and detect improved Ag43 signal peptides. Through just three rounds of mutagenesis and selection using green fluorescence from the 56 kDa sfGFP-beta-lactamase, we isolated clones that modestly increased surface display from 1.4- to 3-fold as detected by the microplate plate-reader and native SDS-PAGE assays. To establish that the functional protein was displayed extracellularly, we trypsinized the bacterial cells to release the surface displayed proteins for analysis. This workflow demonstrated a fast and high-throughput method leveraging epPCR and single-cell sorting to augment bacterial surface display rapidly that could be applied to other bacterial proteins.
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Karyolaimos A, de Gier JW. Strategies to Enhance Periplasmic Recombinant Protein Production Yields in Escherichia coli. Front Bioeng Biotechnol 2021; 9:797334. [PMID: 34970535 PMCID: PMC8712718 DOI: 10.3389/fbioe.2021.797334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 11/24/2021] [Indexed: 11/29/2022] Open
Abstract
Main reasons to produce recombinant proteins in the periplasm of E. coli rather than in its cytoplasm are to -i- enable disulfide bond formation, -ii- facilitate protein isolation, -iii- control the nature of the N-terminus of the mature protein, and -iv- minimize exposure to cytoplasmic proteases. However, hampered protein targeting, translocation and folding as well as protein instability can all negatively affect periplasmic protein production yields. Strategies to enhance periplasmic protein production yields have focused on harmonizing secretory recombinant protein production rates with the capacity of the secretory apparatus by transcriptional and translational tuning, signal peptide selection and engineering, increasing the targeting, translocation and periplasmic folding capacity of the production host, preventing proteolysis, and, finally, the natural and engineered adaptation of the production host to periplasmic protein production. Here, we discuss these strategies using notable examples as a thread.
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Affiliation(s)
| | - Jan-Willem de Gier
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
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