1
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Teng Y, Jiang T, Yan Y. The expanded CRISPR toolbox for constructing microbial cell factories. Trends Biotechnol 2024; 42:104-118. [PMID: 37500408 PMCID: PMC10808275 DOI: 10.1016/j.tibtech.2023.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/29/2023]
Abstract
Microbial cell factories (MCFs) convert low-cost carbon sources into valuable compounds. The CRISPR/Cas9 system has revolutionized MCF construction as a remarkable genome editing tool with unprecedented programmability. Recently, the CRISPR toolbox has been significantly expanded through the exploration of new CRISPR systems, the engineering of Cas effectors, and the incorporation of other effectors, enabling multi-level regulation and gene editing free of double-strand breaks. This expanded CRISPR toolbox powerfully promotes MCF construction by facilitating pathway construction, enzyme engineering, flux redistribution, and metabolic burden control. In this article, we summarize different CRISPR tool designs and their applications in MCF construction for gene editing, transcriptional regulation, and enzyme modulation. Finally, we also discuss future perspectives for the development and application of the CRISPR toolbox.
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Affiliation(s)
- Yuxi Teng
- School of Chemical, Materials and Biomedical Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA
| | - Tian Jiang
- School of Chemical, Materials and Biomedical Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA
| | - Yajun Yan
- School of Chemical, Materials and Biomedical Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA.
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2
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Liu N, Dong W, Yang H, Li JH, Chiu TY. Application of artificial scaffold systems in microbial metabolic engineering. Front Bioeng Biotechnol 2023; 11:1328141. [PMID: 38188488 PMCID: PMC10771841 DOI: 10.3389/fbioe.2023.1328141] [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: 10/26/2023] [Accepted: 12/12/2023] [Indexed: 01/09/2024] Open
Abstract
In nature, metabolic pathways are often organized into complex structures such as multienzyme complexes, enzyme molecular scaffolds, or reaction microcompartments. These structures help facilitate multi-step metabolic reactions. However, engineered metabolic pathways in microbial cell factories do not possess inherent metabolic regulatory mechanisms, which can result in metabolic imbalance. Taking inspiration from nature, scientists have successfully developed synthetic scaffolds to enhance the performance of engineered metabolic pathways in microbial cell factories. By recruiting enzymes, synthetic scaffolds facilitate the formation of multi-enzyme complexes, leading to the modulation of enzyme spatial distribution, increased enzyme activity, and a reduction in the loss of intermediate products and the toxicity associated with harmful intermediates within cells. In recent years, scaffolds based on proteins, nucleic acids, and various organelles have been developed and employed to facilitate multiple metabolic pathways. Despite varying degrees of success, synthetic scaffolds still encounter numerous challenges. The objective of this review is to provide a comprehensive introduction to these synthetic scaffolds and discuss their latest research advancements and challenges.
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Affiliation(s)
- Nana Liu
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China
- HIM-BGI Omics Center, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences (CAS), Hangzhou, China
| | - Wei Dong
- HIM-BGI Omics Center, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences (CAS), Hangzhou, China
| | - Huanming Yang
- HIM-BGI Omics Center, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences (CAS), Hangzhou, China
| | - Jing-Hua Li
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China
| | - Tsan-Yu Chiu
- College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou, China
- HIM-BGI Omics Center, Zhejiang Cancer Hospital, Hangzhou Institute of Medicine (HIM), Chinese Academy of Sciences (CAS), Hangzhou, China
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3
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Zhao H, Xiu X, Li M, Dai S, Gou M, Tao L, Zuo X, Fan C, Tian Z, Song P. Programming Super DNA-Enzyme Molecules for On-Demand Enzyme Activity Modulation. Angew Chem Int Ed Engl 2023; 62:e202214450. [PMID: 36756781 DOI: 10.1002/anie.202214450] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/01/2023] [Accepted: 02/07/2023] [Indexed: 02/10/2023]
Abstract
Dynamic interactions of enzymes, including programmable configuration and cycling of enzymes, play important roles in the regulation of cellular metabolism. Here, we constructed a super DNA-enzymes molecule (SDEM) that comprises at least two cascade enzymes and multiple linked DNA strands to control and detect metabolism. We found that the programmable SDEM, which comprises glucose oxidase (GOx) and horseradish peroxidase (HRP), has a 20-fold lower detection limit and a 1.6-fold higher reaction rate than free enzymes. An SDEM can be assembled and disassembled using a hairpin structure and a displacement DNA strand to complete multiple cycles. An entropically driven catalytic assembly (catassembly) enables different SDEMs to switch from an SDEM with GOx and HRP cascades to an SDEM with sarcosine oxidase (SOX) and HRP cascades in over six orders of magnitude less time than without the catassembly to detect different metabolisms (GO and sarcosine) on demand.
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Affiliation(s)
- Haipei Zhao
- State Key Laboratory of Oncogenes and Related Genes, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xuehao Xiu
- State Key Laboratory of Oncogenes and Related Genes, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Mingqiang Li
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shaobo Dai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Mingyang Gou
- State Key Laboratory of Oncogenes and Related Genes, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Leyang Tao
- State Key Laboratory of Oncogenes and Related Genes, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xiaolei Zuo
- Institute of Molecular Medicine Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine Renji Hospital School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, P. R. China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and National Center for Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhongqun Tian
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Ping Song
- State Key Laboratory of Oncogenes and Related Genes, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, China
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4
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Pham A, Bassett S, Chen W, Da Silva NA. Assembly of Metabolons in Yeast Using Cas6-Mediated RNA Scaffolding. ACS Synth Biol 2023; 12:1164-1174. [PMID: 36920425 DOI: 10.1021/acssynbio.2c00650] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Cells often localize pathway enzymes in close proximity to reduce substrate loss via diffusion and to ensure that carbon flux is directed toward the desired product. To emulate this strategy for the biosynthesis of heterologous products in yeast, we have taken advantage of the highly specific Cas6-RNA interaction and the predictability of RNA hybridizations to demonstrate Cas6-mediated RNA-guided protein assembly within the yeast cytosol. The feasibility of this synthetic scaffolding technique for protein localization was first demonstrated using a split luciferase reporter system with each part fused to a different Cas6 protein. In Saccharomyces cerevisiae, the luminescence signal increased 3.6- to 20-fold when the functional RNA scaffold was also expressed. Expression of a trigger RNA, designed to prevent the formation of a functional scaffold by strand displacement, decreased the luminescence signal by nearly 2.3-fold. Temporal control was also possible, with induction of scaffold expression resulting in an up to 11.6-fold increase in luminescence after 23 h. Cas6-mediated assembly was applied to create a two-enzyme metabolon to redirect a branch of the violacein biosynthesis pathway. Localizing VioC and VioE together increased the amount of deoxyviolacein (desired) relative to prodeoxyviolacein (undesired) by 2-fold. To assess the generality of this colocalization method in other yeast systems, the split luciferase reporter system was evaluated in Kluyveromyces marxianus; RNA scaffold expression resulted in an increase in the luminescence signal of up to 1.9-fold. The simplicity and flexibility of the design suggest that this strategy can be used to create metabolons in a wide range of recombinant hosts of interest.
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Affiliation(s)
- Anhuy Pham
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697-2580, United States
| | - Shane Bassett
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697-2580, United States
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Nancy A Da Silva
- Department of Chemical and Biomolecular Engineering, University of California, Irvine, California 92697-2580, United States
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5
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Nucleic acid-based scaffold systems and application in enzyme cascade catalysis. Appl Microbiol Biotechnol 2022; 107:9-23. [DOI: 10.1007/s00253-022-12315-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 12/05/2022]
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6
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Tsai SL, Sun Q, Chen W. Advances in consolidated bioprocessing using synthetic cellulosomes. Curr Opin Biotechnol 2022; 78:102840. [PMID: 36356377 DOI: 10.1016/j.copbio.2022.102840] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/02/2022] [Accepted: 10/10/2022] [Indexed: 11/09/2022]
Abstract
The primary obstacle impeding the more widespread use of biomass for energy and chemical production is the absence of a low-cost technology for overcoming their recalcitrant nature. It has been shown that the overall cost can be reduced by using a 'consolidated' bioprocessing (CBP) approach, in which enzyme production, biomass hydrolysis, and sugar fermentation can be combined. Cellulosomes are enzyme complexes found in many anaerobic microorganisms that are highly efficient for biomass depolymerization. While initial efforts to display synthetic cellulosomes have been successful, the overall conversion is still low for practical use. This limitation has been partially alleviated by displaying more complex cellulsome structures either via adaptive assembly or by using synthetic consortia. Since synthetic cellulosome nanostructures have also been created using either protein nanoparticles or DNA as a scaffold, there is the potential to tether these nanostructures onto living cells in order to further enhance the overall efficiency.
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Affiliation(s)
- Shen-Long Tsai
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei City 106335, Taiwan
| | - Qing Sun
- Department of Chemical Engineering, Texas A&M University, College Station, TX 77843-3122, USA
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, USA.
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7
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Metabolic pathway assembly using docking domains from type I cis-AT polyketide synthases. Nat Commun 2022; 13:5541. [PMID: 36130947 PMCID: PMC9492657 DOI: 10.1038/s41467-022-33272-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 09/09/2022] [Indexed: 11/21/2022] Open
Abstract
Engineered metabolic pathways in microbial cell factories often have no natural organization and have challenging flux imbalances, leading to low biocatalytic efficiency. Modular polyketide synthases (PKSs) are multienzyme complexes that synthesize polyketide products via an assembly line thiotemplate mechanism. Here, we develop a strategy named mimic PKS enzyme assembly line (mPKSeal) that assembles key cascade enzymes to enhance biocatalytic efficiency and increase target production by recruiting cascade enzymes tagged with docking domains from type I cis-AT PKS. We apply this strategy to the astaxanthin biosynthetic pathway in engineered Escherichia coli for multienzyme assembly to increase astaxanthin production by 2.4-fold. The docking pairs, from the same PKSs or those from different cis-AT PKSs evidently belonging to distinct classes, are effective enzyme assembly tools for increasing astaxanthin production. This study addresses the challenge of cascade catalytic efficiency and highlights the potential for engineering enzyme assembly. Assembly artificial pathway in design connecting media can increase biosynthetic efficiency, but the choice of connecting media is limited. Here, the authors develop a new protein assembly strategy using a pool of docking peptides from polyketide synthase and show its application in astaxanthin biosynthesis in E. coli.
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8
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Dynamic modulation of enzyme activity by synthetic CRISPR–Cas6 endonucleases. Nat Chem Biol 2022; 18:492-500. [DOI: 10.1038/s41589-022-01005-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 02/25/2022] [Indexed: 11/08/2022]
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9
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Hunt VM, Chen W. Deciphering the Design Rules of Toehold-Gated sgRNA for Conditional Activation of Gene Expression and Protein Degradation in Mammalian Cells. ACS Synth Biol 2022; 11:397-405. [PMID: 34994551 DOI: 10.1021/acssynbio.1c00479] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A new class of toehold-gated gRNAs (thgRNAs) has been created to provide conditional gene regulation via RNA-mediated activation. However, the detailed design principles remain elusive. Here, we presented an investigation into the design rules for conditional gRNAs by systematically varying the toehold, stem, and flexible loop regions of thgRNA for optimal gene activation in HeLa cells. We determined that nonspecific interactions between the toehold region and the flexible loop are the main driver for the background leak observed in the OFF state. By trimming the toehold length from 15 to 5 nt, the improved thgNT-F design led to a 38-fold increase in the activated ON state with no observable background leak. The same design rule was successfully adapted to target two different regions on the mCherry mRNA with the same impressive fold change. Using the thgRNA to direct conditional protein degradation, we showed up to 8-fold knockdown of a reporter protein through activating expression of a bifunctional ubiquibody GS2-IpaH9.8. This new strategy may find many new applications for cell culture control or cell therapy by removing unwanted proteins in an RNA-responsive manner.
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Affiliation(s)
- Victoria M Hunt
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
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10
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Sun Q, Raeeszadeh-Sarmazdeh M, Tsai SL, Chen W. Strategies for Multienzyme Assemblies. Methods Mol Biol 2022; 2487:113-131. [PMID: 35687232 DOI: 10.1007/978-1-0716-2269-8_7] [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] [Indexed: 06/15/2023]
Abstract
Proteins are not designed to be standalone entities and must coordinate their collective action for optimum performance. Nature has developed through evolution the ability to co-localize the functional partners of a cascade enzymatic reaction in order to ensure efficient exchange of intermediates. Inspired by these natural designs, synthetic scaffolds have been created to enhance the overall biological pathway performance. In this chapter, we describe several DNA- and protein-based scaffold approaches to assemble artificial enzyme cascades for a wide range of applications. We highlight the key benefits and drawbacks of these approaches to provide insights on how to choose the appropriate scaffold for different cascade systems.
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Affiliation(s)
- Qing Sun
- Department of Chemical Engineering, Texas A&M University, College Station, TX, USA
| | | | - Shen-Long Tsai
- Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei City, Taiwan
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA.
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11
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Berckman EA, Chen W. Self-assembling protein nanocages for modular enzyme assembly by orthogonal bioconjugation. Biotechnol Prog 2021; 37:e3190. [PMID: 34173352 DOI: 10.1002/btpr.3190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/03/2021] [Accepted: 06/24/2021] [Indexed: 11/06/2022]
Abstract
The wide variety of enzymatic pathways that can benefit from enzyme scaffolding is astronomical. While enzyme co-localization based on protein, DNA, and RNA scaffolds has been reported, we still lack scaffolds that offer well-defined and uniform three-dimensional structures for enzyme organization. Here we reported a new approach for protein co-localization using naturally occurring protein nanocages as a scaffold. Two different nanocages, the 25 nm E2 and the 34 nm heptatitis B virus, were used to demonstrate the successfully co-localization of the endoglucanase CelA and cellulose binding domain using the robust SpyTag/SpyCatcher bioconjugation chemistry. Because of the simplicity of the assembly, this strategy is useful not only for in vivo enzyme cascading but also the potential for in vivo applications as well.
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Affiliation(s)
- Emily A Berckman
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
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12
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Labun K, Krause M, Torres Cleuren Y, Valen E. CRISPR Genome Editing Made Easy Through the CHOPCHOP Website. Curr Protoc 2021; 1:e46. [PMID: 33905612 DOI: 10.1002/cpz1.46] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The design of optimal guide RNA (gRNA) sequences for CRISPR systems is challenged by the need to achieve highly efficient editing at the desired location (on-target editing) with minimal editing at unintended locations (off-target editing). Although laboratory validation should ideally be used to detect off-target activity, computational predictions are almost always preferred in practice due to their speed and low cost. Several studies have therefore explored gRNA-DNA interactions in order to understand how CRISPR complexes select their genomic targets. CHOPCHOP (https://chopchop.cbu.uib.no/) leverages these developments to build a user-friendly web interface that helps users design optimal gRNAs. CHOPCHOP supports a wide range of CRISPR applications, including gene knock-out, sequence knock-in, and RNA knock-down. Furthermore, CHOPCHOP offers visualization that enables an informed choice of gRNAs and supports experimental validation. In these protocols, we describe the best practices for gRNA design using CHOPCHOP. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Design of gRNAs for gene knock-out Alternate Protocol 1: Design of gRNAs for dCas9 fusion/effector targeting Support Protocol: Design of gRNAs for targeting transgenic or plasmid sequences Basic Protocol 2: Design of gRNAs for RNA targeting Basic Protocol 3: Design of gRNAs for sequence knock-in Alternate Protocol 2: Design of gRNAs for knock-in using non-homologous end joining Basic Protocol 4: Design of gRNAs for knock-in using Cas9 nickases.
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Affiliation(s)
- Kornel Labun
- Department of Informatics, Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Maximilian Krause
- Department of Informatics, Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Yamila Torres Cleuren
- Department of Informatics, Computational Biology Unit, University of Bergen, Bergen, Norway
| | - Eivind Valen
- Department of Informatics, Computational Biology Unit, University of Bergen, Bergen, Norway
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13
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Lim S, Kim J, Kim Y, Xu D, Clark DS. CRISPR/Cas-directed programmable assembly of multi-enzyme complexes. Chem Commun (Camb) 2020; 56:4950-4953. [PMID: 32239050 DOI: 10.1039/d0cc01174f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe a versatile CRISPR/Cas-based strategy to construct multi-enzyme complexes scaffolded on a DNA template in programmable patterns. Catalytically inactive dCas9 nuclease was used in combination with SpyCatcher-SpyTag chemistry to assemble enzymes in a highly modular fashion. Five enzymes comprising the violacein biosynthesis pathway were precisely organized in nanometer proximity; a notable increase in violacein production demonstrated the benefits of scaffolding.
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Affiliation(s)
- Samuel Lim
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
| | - Jiwoo Kim
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
| | - Yujin Kim
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
| | - Dawei Xu
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
| | - Douglas S Clark
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA. and Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
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14
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Berckman EA, Chen W. A modular approach for dCas9-mediated enzyme cascading via orthogonal bioconjugation. Chem Commun (Camb) 2020; 56:11426-11428. [PMID: 32840530 DOI: 10.1039/d0cc04196c] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We report a new modular strategy to assemble dCas9-guided enzyme cascades by employing orthogonal post-translation chemistry. Two orthogonal SpyCatcher and SnoopCatcher pairs were used for the one-pot enzyme bioconjugation onto two different dCas9 proteins to enable their guided assembly onto a DNA scaffold. The resulting two-component cellulosomes exhibited 2.8-fold higher reducing sugar production over unassembled enzymes. This platform retains the high binding affinity afforded by dCas9 proteins for easy control over enzyme assembly while offering the flexibility for both in vivo and in vitro assembly of a wide array of enzyme cascades with minimal optimization.
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Affiliation(s)
- Emily A Berckman
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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15
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Lv Y, Gu Y, Xu J, Zhou J, Xu P. Coupling metabolic addiction with negative autoregulation to improve strain stability and pathway yield. Metab Eng 2020; 61:79-88. [PMID: 32445959 PMCID: PMC7510839 DOI: 10.1016/j.ymben.2020.05.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 05/14/2020] [Indexed: 11/23/2022]
Abstract
Metabolic addiction, an organism that is metabolically addicted with a compound to maintain its growth fitness, is an underexplored area in metabolic engineering. Microbes with heavily engineered pathways or genetic circuits tend to experience metabolic burden leading to degenerated or abortive production phenotype during long-term cultivation or scale-up. A promising solution to combat metabolic instability is to tie up the end-product with an intermediary metabolite that is essential to the growth of the producing host. Here we present a simple strategy to improve both metabolic stability and pathway yield by coupling chemical addiction with negative autoregulatory genetic circuits. Naringenin and lipids compete for the same precursor malonyl-CoA with inversed pathway yield in oleaginous yeast. Negative autoregulation of the lipogenic pathways, enabled by CRISPRi and fatty acid-inducible promoters, repartitions malonyl-CoA to favor flavonoid synthesis and increased naringenin production by 74.8%. With flavonoid-sensing transcriptional activator FdeR and yeast hybrid promoters to control leucine synthesis and cell grwoth fitness, this amino acid feedforward metabolic circuit confers a flavonoid addiction phenotype that selectively enrich the naringenin-producing pupulation in the leucine auxotrophic yeast. The engineered yeast persisted 90.9% of naringenin titer up to 324 generations. Cells without flavonoid addiction regained growth fitness but lost 94.5% of the naringenin titer after cell passage beyond 300 generations. Metabolic addiction and negative autoregulation may be generalized as basic tools to eliminate metabolic heterogeneity, improve strain stability and pathway yield in long-term and large-scale bioproduction.
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Affiliation(s)
- Yongkun Lv
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA; School of Chemical Engineering, Zhengzhou University, Zhengzhou, Henan, 450001, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Yang Gu
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China
| | - Jingliang Xu
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, Henan, 450001, China.
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, Jiangsu, 214122, China.
| | - Peng Xu
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, 21250, USA.
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16
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Controlling metabolic flux by toehold-mediated strand displacement. Curr Opin Biotechnol 2020; 66:150-157. [PMID: 32801094 DOI: 10.1016/j.copbio.2020.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 07/02/2020] [Accepted: 07/05/2020] [Indexed: 01/03/2023]
Abstract
To maximize desired products in engineered cellular factories it is often necessary to optimize metabolic flux. While a number of works have focused on metabolic pathway enhancement through genetic regulators and synthetic scaffolds, these approaches require time-intensive design and optimization with limited versatility and capacity for scale-up. Recently, nucleic-acid nanotechnology has emerged as an encouraging approach to overcome these limitations and create systems for modular programmable control of metabolic flux. Using toehold-mediated strand displacement (TMSD), nucleic acid constructs can be made into dynamic devices that recognize specific biomolecular triggers for conditional control of gene regulation as well as design of dynamic synthetic scaffolds. This review will consider the various approaches that have been used thus far to control metabolic flux using toehold-gated devices.
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17
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Berckman EA, Hartzell EJ, Mitkas AA, Sun Q, Chen W. Biological Assembly of Modular Protein Building Blocks as Sensing, Delivery, and Therapeutic Agents. Annu Rev Chem Biomol Eng 2020; 11:35-62. [PMID: 32155350 DOI: 10.1146/annurev-chembioeng-101519-121526] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nature has evolved a wide range of strategies to create self-assembled protein nanostructures with structurally defined architectures that serve a myriad of highly specialized biological functions. With the advent of biological tools for site-specific protein modifications and de novo protein design, a wide range of customized protein nanocarriers have been created using both natural and synthetic biological building blocks to mimic these native designs for targeted biomedical applications. In this review, different design frameworks and synthetic decoration strategies for achieving these functional protein nanostructures are summarized. Key attributes of these designer protein nanostructures, their unique functions, and their impact on biosensing and therapeutic applications are discussed.
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Affiliation(s)
- Emily A Berckman
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA; .,Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | - Emily J Hartzell
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA;
| | - Alexander A Mitkas
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA;
| | - Qing Sun
- Department of Chemical Engineering, Texas A&M University, College Station, Texas 77843, USA
| | - Wilfred Chen
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA;
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