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OverFlap PCR: A reliable approach for generating plasmid DNA libraries containing random sequences without a template bias. PLoS One 2022; 17:e0262968. [PMID: 35939421 PMCID: PMC9359533 DOI: 10.1371/journal.pone.0262968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 07/17/2022] [Indexed: 11/19/2022] Open
Abstract
Over the decades, practical biotechnology researchers have aimed to improve naturally occurring proteins and create novel ones. It is widely recognized that coupling protein sequence randomization with various effect screening methodologies is one of the most powerful techniques for quickly, efficiently, and purposefully acquiring these desired improvements. Over the years, considerable advancements have been made in this field. However, developing PCR-based or template-guided methodologies has been hampered by resultant template sequence biases. Here, we present a novel whole plasmid amplification-based approach, which we named OverFlap PCR, for randomizing virtually any region of plasmid DNA without introducing a template sequence bias.
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Peng B, Dikdan R, Hill SE, Patterson-Orazem AC, Lieberman RL, Fahrni CJ, Dickson RM. Optically Modulated and Optically Activated Delayed Fluorescent Proteins through Dark State Engineering. J Phys Chem B 2021; 125:5200-5209. [PMID: 33978414 DOI: 10.1021/acs.jpcb.1c00649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modulating fluorescent protein emission holds great potential for increasing readout sensitivity for applications in biological imaging and detection. Here, we identify and engineer optically modulated yellow fluorescent proteins (EYFP, originally 10C, but renamed EYFP later, and mVenus) to yield new emitters with distinct modulation profiles and unique, optically gated, delayed fluorescence. The parent YFPs are individually modulatable through secondary illumination, depopulating a long-lived dark state to dynamically increase fluorescence. A single point mutation introduced near the chromophore in each of these YFPs provides access to a second, even longer-lived modulatable dark state, while a different double mutant renders EYFP unmodulatable. The naturally occurring dark state in the parent YFPs yields strong fluorescence modulation upon long-wavelength-induced dark state depopulation, allowing selective detection at the frequency at which the long wavelength secondary laser is intensity modulated. Distinct from photoswitches, however, this near IR secondary coexcitation repumps the emissive S1 level from the long-lived triplet state, resulting in optically activated delayed fluorescence (OADF). This OADF results from secondary laser-induced, reverse intersystem crossing (RISC), producing additional nanosecond-lived, visible fluorescence that is delayed by many microseconds after the primary excitation has turned off. Mutation of the parent chromophore environment opens an additional modulation pathway that avoids the OADF-producing triplet state, resulting in a second, much longer-lived, modulatable dark state. These Optically Modulated and Optically Activated Delayed Fluorescent Proteins (OMFPs and OADFPs) are thus excellent for background- and reference-free, high sensitivity cellular imaging, but time-gated OADF offers a second modality for true background-free detection. Our combined structural and spectroscopic data not only gives additional mechanistic details for designing optically modulated fluorescent proteins but also provides the opportunity to distinguish similarly emitting OMFPs through OADF and through their unique modulation spectra.
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Affiliation(s)
- Baijie Peng
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Ryan Dikdan
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Shannon E Hill
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Athéna C Patterson-Orazem
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Christoph J Fahrni
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Robert M Dickson
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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Fu X, Zhang Y, Xu Q, Sun X, Meng F. Recent Advances on Sorting Methods of High-Throughput Droplet-Based Microfluidics in Enzyme Directed Evolution. Front Chem 2021; 9:666867. [PMID: 33996758 PMCID: PMC8114877 DOI: 10.3389/fchem.2021.666867] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/02/2021] [Indexed: 11/24/2022] Open
Abstract
Droplet-based microfluidics has been widely applied in enzyme directed evolution (DE), in either cell or cell-free system, due to its low cost and high throughput. As the isolation principles are based on the labeled or label-free characteristics in the droplets, sorting method contributes mostly to the efficiency of the whole system. Fluorescence-activated droplet sorting (FADS) is the mostly applied labeled method but faces challenges of target enzyme scope. Label-free sorting methods show potential to greatly broaden the microfluidic application range. Here, we review the developments of droplet sorting methods through a comprehensive literature survey, including labeled detections [FADS and absorbance-activated droplet sorting (AADS)] and label-free detections [electrochemical-based droplet sorting (ECDS), mass-activated droplet sorting (MADS), Raman-activated droplet sorting (RADS), and nuclear magnetic resonance-based droplet sorting (NMR-DS)]. We highlight recent cases in the last 5 years in which novel enzymes or highly efficient variants are generated by microfluidic DE. In addition, the advantages and challenges of different sorting methods are briefly discussed to provide an outlook for future applications in enzyme DE.
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Affiliation(s)
- Xiaozhi Fu
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Yueying Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Qiang Xu
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Xiaomeng Sun
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Fanda Meng
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Medicine and Health Key Laboratory of Laboratory Medicine, Jinan, China
- School of Basic Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
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Hejlesen R, Füchtbauer EM. Multiple site-directed mutagenesis via simple cloning by prolonged overlap extension. Biotechniques 2020; 68:345-348. [PMID: 32372650 DOI: 10.2144/btn-2019-0104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We describe the application of simple cloning by prolonged overlap extension for multiple site-directed mutagenesis in the same plasmid. We show that it is possible to use this technique with very short PCR templates. The technique is ideally suited for the generation of longer donor DNA sequences for CRISPR/Cas9-mediated homologous repair.
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Affiliation(s)
- Rasmus Hejlesen
- Department of Molecular Biology & Genetics, Aarhus University, C.F. Møllers Allé 3, 8000 Aarhus C, Denmark
| | - Ernst-Martin Füchtbauer
- Department of Molecular Biology & Genetics, Aarhus University, C.F. Møllers Allé 3, 8000 Aarhus C, Denmark
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Janesch B, Baumann L, Mark A, Thompson N, Rahmani S, Sim L, Withers SG, Wakarchuk WW. Directed evolution of bacterial polysialyltransferases. Glycobiology 2020; 29:588-598. [PMID: 30976781 DOI: 10.1093/glycob/cwz021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/15/2019] [Accepted: 03/18/2019] [Indexed: 01/30/2023] Open
Abstract
Polysialyltransferases (polySTs) are glycosyltransferases that synthesize polymers of sialic acid found in vertebrates and some bacterial pathogens. Bacterial polySTs have utility in the modification of therapeutic proteins to improve serum half-life, and the potential for tissue engineering. PolySTs are membrane-associated proteins and as recombinant proteins suffer from inherently low solubility, low expression levels and poor thermal stability. To improve their physicochemical and biochemical properties, we applied a directed evolution approach using a FACS-based ultrahigh-throughput assay as a simple, robust and reliable screening method. We were able to enrich a large mutant library and, in combination with plate-based high-throughput secondary screening, we discovered mutants with increased enzymatic activity and improved stability compared to the wildtype enzyme. This work presents a powerful strategy for the screening of directed evolution libraries of bacterial polySTs to identify better catalysts for in vitro polysialylation of therapeutics.
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Affiliation(s)
- Bettina Janesch
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Lars Baumann
- Departments of Chemistry and Biochemistry, and Michael Smith Laboratory, University of British Columbia, Vancouver, BC, Canada
| | - Alison Mark
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Nicole Thompson
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Sadia Rahmani
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Lyann Sim
- Departments of Chemistry and Biochemistry, and Michael Smith Laboratory, University of British Columbia, Vancouver, BC, Canada
| | - Stephen G Withers
- Departments of Chemistry and Biochemistry, and Michael Smith Laboratory, University of British Columbia, Vancouver, BC, Canada
| | - Warren W Wakarchuk
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
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Identification and characterization of sequence signatures in the Bacillus subtilis promoter P ylb for tuning promoter strength. Biotechnol Lett 2019; 42:115-124. [PMID: 31691164 PMCID: PMC6940355 DOI: 10.1007/s10529-019-02749-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/18/2019] [Indexed: 01/24/2023]
Abstract
Objective To thoroughly characterize the Pylb promoter and identify the elements that affect the promoter activity. Result The sequences flanking the − 35 and − 10 box of the Pylb promoter were divided into six segments, and six random-scanning mutant promoter libraries fused to an enhanced green fluorescent protein EGFP were made and analyzed by flow cytometry. Our results showed that the four nucleotides flanking the − 35 box could mostly influence the promoter activity, and this influence was related to the GC content. The promoters mutated in these regions were successfully used for expressing the gene ophc2 encoding organophosphorus hydrolase (OPHC2) and the gene katA encoding catalase (KatA). Conclusion Our work identified and characterized the sequence signatures of the Pylb promoter that could tune the promoter strength, providing further information for the potential application of this promoter. Meanwhile, the sequence signatures have the potential to be used for tuning gene expression in enzyme production, metabolic engineering, and synthetic biology. Electronic supplementary material The online version of this article (10.1007/s10529-019-02749-4) contains supplementary material, which is available to authorized users.
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Huang R, Chen H, Zhou W, Ma C, Zhang YHP. Engineering a thermostable highly active glucose 6-phosphate dehydrogenase and its application to hydrogen production in vitro. Appl Microbiol Biotechnol 2018; 102:3203-3215. [DOI: 10.1007/s00253-018-8798-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/16/2018] [Accepted: 01/18/2018] [Indexed: 10/17/2022]
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Zhong C, You C, Wei P, Zhang YHP. Simple Cloning by Prolonged Overlap Extension-PCR with Application to the Preparation of Large-Size Random Gene Mutagenesis Library in Escherichia coli. Methods Mol Biol 2017; 1472:49-61. [PMID: 27671931 DOI: 10.1007/978-1-4939-6343-0_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We developed a simple method (simple cloning) for subcloning DNA fragments into any location of a targeted vector without the need of restriction enzyme, ligase, exonuclease, or recombinase in Escherichia coli. This technology can be applied to common E. coli hosts (e.g., DH5α, JM109, TOP10, BL21(DE3)). The protocol includes three steps: (1) generate DNA insert and linear vector backbone by regular high-fidelity PCR, where these two DNA fragments contain 3' and 5' overlapping termini; (2) generate DNA multimers based on these two DNA fragments by using prolonged overlap extension-PCR (POE-PCR) without primers added; and (3) transform POE-PCR product to competent Escherichia coli cells directly, yielding the desired plasmid. Simple cloning provides a new cloning method with great simplicity and flexibility. Furthermore, this new method can be modified for the preparation of a large-size mutant library for directed evolution in E. coli. Using this method, it is very easy to generate a mutant library with a size of more than 10(7) per 50 μL of the POE-PCR product within 1 day.
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Affiliation(s)
- Chao Zhong
- Biological Systems Engineering Department, Virginia Tech, 304 Seitz Hall, Blacksburg, VA, 24061, USA
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30th Puzhu South St, Nanjing, 211800, China
| | - Chun You
- Biological Systems Engineering Department, Virginia Tech, 304 Seitz Hall, Blacksburg, VA, 24061, USA
- Cell Free Bioinnovations Inc., 1800 Kraft Drive, Suite 200, Blacksburg, VA, 24060, USA
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Ping Wei
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30th Puzhu South St, Nanjing, 211800, China
| | - Yi-Heng Percival Zhang
- Biological Systems Engineering Department, Virginia Tech, 304 Seitz Hall, Blacksburg, VA, 24061, USA.
- Cell Free Bioinnovations Inc., 1800 Kraft Drive, Suite 200, Blacksburg, VA, 24060, USA.
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China.
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Kim JE, Huang R, Chen H, You C, Zhang YHP. Facile Construction of Random Gene Mutagenesis Library for Directed Evolution Without the Use of Restriction Enzyme in Escherichia coli. Biotechnol J 2016; 11:1142-50. [PMID: 27367290 DOI: 10.1002/biot.201600121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 06/21/2016] [Accepted: 06/27/2016] [Indexed: 12/16/2022]
Abstract
A foolproof protocol was developed for the construction of mutant DNA library for directed protein evolution. First, a library of linear mutant gene was generated by error-prone PCR or molecular shuffling, and a linear vector backbone was prepared by high-fidelity PCR. Second, the amplified insert and vector fragments were assembled by overlap-extension PCR with a pair of 5'-phosphorylated primers. Third, full-length linear plasmids with phosphorylated 5'-ends were self-ligated with T4 ligase, yielding circular plasmids encoding mutant variants suitable for high-efficiency transformation. Self-made competent Escherichia coli BL21(DE3) showed a transformation efficiency of 2.4 × 10(5) cfu/µg of the self-ligated circular plasmid. Using this method, three mutants of mCherry fluorescent protein were found to alter their colors and fluorescent intensities under visible and UV lights, respectively. Also, one mutant of 6-phosphorogluconate dehydrogenase from a thermophilic bacterium Moorella thermoacetica was found to show the 3.5-fold improved catalytic efficiency (kcat /Km ) on NAD(+) as compared to the wild-type. This protocol is DNA-sequence independent, and does not require restriction enzymes, special E. coli host, or labor-intensive optimization. In addition, this protocol can be used for subcloning the relatively long DNA sequences into any position of plasmids.
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Affiliation(s)
- Jae-Eung Kim
- Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA, USA
| | - Rui Huang
- Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA, USA
| | - Hui Chen
- Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA, USA
| | - Chun You
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Y-H Percival Zhang
- Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA, USA.
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
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Lectin engineering, a molecular evolutionary approach to expanding the lectin utilities. Molecules 2015; 20:7637-56. [PMID: 25923514 PMCID: PMC6272786 DOI: 10.3390/molecules20057637] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 04/20/2015] [Accepted: 04/20/2015] [Indexed: 11/18/2022] Open
Abstract
In the post genomic era, glycomics—the systematic study of all glycan structures of a given cell or organism—has emerged as an indispensable technology in various fields of biology and medicine. Lectins are regarded as “decipherers of glycans”, being useful reagents for their structural analysis, and have been widely used in glycomic studies. However, the inconsistent activity and availability associated with the plant-derived lectins that comprise most of the commercially available lectins, and the limit in the range of glycan structures covered, have necessitated the development of innovative tools via engineering of lectins on existing scaffolds. This review will summarize the current state of the art of lectin engineering and highlight recent technological advances in this field. The key issues associated with the strategy of lectin engineering including selection of template lectin, construction of a mutagenesis library, and high-throughput screening methods are discussed.
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You C, Zhang YHP. Simple cloning and DNA assembly in Escherichia coli by prolonged overlap extension PCR. Methods Mol Biol 2014; 1116:183-92. [PMID: 24395365 DOI: 10.1007/978-1-62703-764-8_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We developed a simple method (Simple Cloning) for subcloning one, two, or three DNA fragments into any location of a targeted vector without the need for restriction enzyme, ligase, exonuclease, or recombinase. This cloning technology can be applied to a few common Escherichia coli hosts (e.g., BL21(DE3), DH5α, JM109, TOP10). The protocol includes three steps: (a) linear DNA fragments (i.e., the insert DNA and the vector backbone) with two overlap ends were generated by regular high-fidelity PCR, (b) the DNA multimers were generated based on these equimolar DNA templates by using prolonged overlap extension PCR (POE-PCR) without primers added, and (c) the POE-PCR product was transformed to E. coli strains directly. Because positive colony efficiencies are very high, it is not necessary to identify desired clones by using colony PCR. Simple Cloning provides a new cloning and DNA assembly method with great simplicity and flexibility.
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Affiliation(s)
- Chun You
- Biological Systems Engineering Department, Virginia Tech, Blacksburg, VA, USA
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Ruff AJ, Dennig A, Schwaneberg U. To get what we aim for - progress in diversity generation methods. FEBS J 2013; 280:2961-78. [DOI: 10.1111/febs.12325] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/23/2013] [Accepted: 04/25/2013] [Indexed: 01/06/2023]
Affiliation(s)
- Anna J. Ruff
- Lehrstuhl für Biotechnologie; RWTH Aachen University; Germany
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