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Hume AJ, Deeney DJ, Smetana JS, Turcinovic J, Connor JH, Belfort M, Mühlberger E, Lennon CW. Improved protein splicing through viral passaging. mBio 2024; 15:e0098424. [PMID: 38780266 PMCID: PMC11237716 DOI: 10.1128/mbio.00984-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
Intervening proteins (inteins) are translated as subdomains within host proteins and removed through an intein-driven splicing reaction where the flanking sequences (exteins) are joined with a peptide bond. Previously, we developed a self-removing translation reporter for labeling Ebola virus (EBOV). In this reporter, an intein (RadA) containing the fluorescent protein ZsGreen (ZsG) is inserted within the EBOV protein VP30. Upon VP30-RadA-ZsG expression from the viral genome, RadA-ZsG is removed from VP30 through the protein splicing activity of RadA, generating functional, non-tagged VP30 and functional ZsGreen. While incorporation of our VP30-RadA-ZsG fusion reporter into recombinant EBOV (rEBOV-RadA-ZsG) resulted in an infectious virus that expresses ZsG upon infection of cells, this virus displayed a replication defect compared to wild-type EBOV, which might be the result of insufficient RadA splicing. Here, we demonstrate that the serial passaging of rEBOV-RadA-ZsG in human cells led to an increase in replication efficiency compared to unpassaged rEBOV-RadA-ZsG. Sequencing of passaged viruses revealed intein-specific mutations. These mutations improve intein activity in both prokaryotic and eukaryotic systems, as well as in multiple extein contexts. Taken together, our findings offer a novel means to select for inteins with enhanced catalytic properties that appear independent of extein context and expression system.IMPORTANCEIntervening proteins (inteins) are self-removing protein elements that have been utilized to develop a variety of innovative protein engineering technologies. Here, we report the isolation of inteins with improved catalytic activity through viral passaging. Specifically, we inserted a highly active intein within an essential protein of Ebola virus and serially passaged this recombinant virus, which led to intein-specific hyper-activity mutations. The identified mutations showed improved intein activity within both bacterial and eukaryotic expression systems and in multiple extein contexts. These results present a new strategy for developing inteins with improved splicing activity.
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Affiliation(s)
- Adam J Hume
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
- Center for Emerging Infectious Diseases Policy & Research, Boston University, Boston, Massachusetts, USA
| | - Dylan J Deeney
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
| | - John S Smetana
- Department of Biological Sciences, Murray State University, Murray, Kentucky, USA
| | - Jacquelyn Turcinovic
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
| | - John H Connor
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
- Center for Emerging Infectious Diseases Policy & Research, Boston University, Boston, Massachusetts, USA
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, New York, USA
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
| | - Christopher W Lennon
- Department of Biological Sciences, Murray State University, Murray, Kentucky, USA
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2
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Schmitz M, Ballestin JB, Liang J, Tomas F, Freist L, Voigt K, Di Ventura B, Öztürk MA. Int&in: A machine learning-based web server for active split site identification in inteins. Protein Sci 2024; 33:e4985. [PMID: 38717278 PMCID: PMC11078102 DOI: 10.1002/pro.4985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 03/06/2024] [Accepted: 03/24/2024] [Indexed: 05/12/2024]
Abstract
Inteins are proteins that excise themselves out of host proteins and ligate the flanking polypeptides in an auto-catalytic process called protein splicing. In nature, inteins are either contiguous or split. In the case of split inteins, the two fragments must first form a complex for the splicing to occur. Contiguous inteins have previously been artificially split in two fragments because split inteins allow for distinct applications than contiguous ones. Even naturally split inteins have been split at unnatural split sites to obtain fragments with reduced affinity for one another, which are useful to create conditional inteins or to study protein-protein interactions. So far, split sites in inteins have been heuristically identified. We developed Int&in, a web server freely available for academic research (https://intein.biologie.uni-freiburg.de) that runs a machine learning model using logistic regression to predict active and inactive split sites in inteins with high accuracy. The model was trained on a dataset of 126 split sites generated using the gp41-1, Npu DnaE and CL inteins and validated using 97 split sites extracted from the literature. Despite the limited data size, the model, which uses various protein structural features, as well as sequence conservation information, achieves an accuracy of 0.79 and 0.78 for the training and testing sets, respectively. We envision Int&in will facilitate the engineering of novel split inteins for applications in synthetic and cell biology.
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Affiliation(s)
- Mirko Schmitz
- BIOSS and CIBSS Research Signalling Centers, University of FreiburgFreiburgGermany
- Institute of Biology II, University of FreiburgFreiburgGermany
- 4HF Biotec GmbHFreiburgGermany
| | - Jara Ballestin Ballestin
- BIOSS and CIBSS Research Signalling Centers, University of FreiburgFreiburgGermany
- Institute of Biology II, University of FreiburgFreiburgGermany
- Bioprocess Innovation Unit, ViraTherapeutics GmbHRumAustria
| | - Junsheng Liang
- BIOSS and CIBSS Research Signalling Centers, University of FreiburgFreiburgGermany
- Institute of Biology II, University of FreiburgFreiburgGermany
| | - Franziska Tomas
- BIOSS and CIBSS Research Signalling Centers, University of FreiburgFreiburgGermany
- Institute of Biology II, University of FreiburgFreiburgGermany
- Department of Molecular Life SciencesUniversity of ZurichZurichSwitzerland
| | - Leon Freist
- Institute of Biology III, University of FreiburgFreiburgGermany
| | - Karsten Voigt
- Institute of Biology III, University of FreiburgFreiburgGermany
| | - Barbara Di Ventura
- BIOSS and CIBSS Research Signalling Centers, University of FreiburgFreiburgGermany
- Institute of Biology II, University of FreiburgFreiburgGermany
| | - Mehmet Ali Öztürk
- BIOSS and CIBSS Research Signalling Centers, University of FreiburgFreiburgGermany
- Institute of Biology II, University of FreiburgFreiburgGermany
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3
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Sarkar D, Galleano I, Heusser SA, Ou SY, Uzun GR, Khoo KK, van der Heden van Noort GJ, Harrison JS, Pless SA. Protein semisynthesis underscores the role of a conserved lysine in activation and desensitization of acid-sensing ion channels. Cell Chem Biol 2024; 31:1000-1010.e6. [PMID: 38113885 DOI: 10.1016/j.chembiol.2023.11.013] [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: 01/24/2023] [Revised: 07/21/2023] [Accepted: 11/28/2023] [Indexed: 12/21/2023]
Abstract
Acid-sensing ion channels (ASICs) are trimeric ion channels that open a cation-conducting pore in response to proton binding. Excessive ASIC activation during prolonged acidosis in conditions such as inflammation and ischemia is linked to pain and stroke. A conserved lysine in the extracellular domain (Lys211 in mASIC1a) is suggested to play a key role in ASIC function. However, the precise contributions are difficult to dissect with conventional mutagenesis, as replacement of Lys211 with naturally occurring amino acids invariably changes multiple physico-chemical parameters. Here, we study the contribution of Lys211 to mASIC1a function using tandem protein trans-splicing (tPTS) to incorporate non-canonical lysine analogs. We conduct optimization efforts to improve splicing and functionally interrogate semisynthetic mASIC1a. In combination with molecular modeling, we show that Lys211 charge and side-chain length are crucial to activation and desensitization, thus emphasizing that tPTS can enable atomic-scale interrogations of membrane proteins in live cells.
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Affiliation(s)
- Debayan Sarkar
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Iacopo Galleano
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark; Department of Cell and Chemical Biology, Leiden University Medical Centre, Leiden, the Netherlands
| | | | - Sofie Yuewei Ou
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Gül Refika Uzun
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Keith K Khoo
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark
| | | | | | - Stephan Alexander Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen, Denmark.
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4
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Abstract
The ability to manipulate the chemical composition of proteins and peptides has been central to the development of improved polypeptide-based therapeutics and has enabled researchers to address fundamental biological questions that would otherwise be out of reach. Protein ligation, in which two or more polypeptides are covalently linked, is a powerful strategy for generating semisynthetic products and for controlling polypeptide topology. However, specialized tools are required to efficiently forge a peptide bond in a chemoselective manner with fast kinetics and high yield. Fortunately, nature has addressed this challenge by evolving enzymatic mechanisms that can join polypeptides using a diverse set of chemical reactions. Here, we summarize how such nature-inspired protein ligation strategies have been repurposed as chemical biology tools that afford enhanced control over polypeptide composition.
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Affiliation(s)
- Rasmus Pihl
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Qingfei Zheng
- Department of Radiation Oncology, College of Medicine, The Ohio State University, Columbus, OH, USA.
- Center for Cancer Metabolism, James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA.
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, USA.
| | - Yael David
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA.
- Department of Physiology, Biophysics and Systems Biology, Weill Cornell Medicine, New York, NY, USA.
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5
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Heterologous expression of hAID in E. coli leads to the production of a splice isoform of AID: hAIDδC, a mystery to be explored. Protein Expr Purif 2022; 199:106149. [PMID: 35952962 DOI: 10.1016/j.pep.2022.106149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 11/21/2022]
Abstract
Activation-induced cytidine deaminase (AID) is a key player that initiates antibody diversification in activated B-cell. AID mediates somatic hypermutation (SHM) and class switch recombination (CSR) via the deamination of cytosine to uracil at the Ig locus, resulting in the production of high-affinity antibodies. AID is predominantly restricted to Ig genes, whereas off-targeting of AID leads to lymphocyte-related malignancies. Interestingly, apart from FL-AID other splice isoforms of AID are highly expressed in the lymphocyte malignancies. In our study, we found that the heterologous expression of hAID-FL in E. coli cells produced two induced bands of hAID as demonstrated by SDS-PAGE and western blotting. Remarkably, peptide mapping data predicted that one band is hAID-FL and the other is its splice isoform, hAIDδE4a. To get an insight into why E. coli cells expressed hAID-FL and hAID variant, we mutated the 5' and 3' splice site of a putative intron of hAID, but it failed to produce only hAID-FL. Incidentally, hAID expressed with fusion partners also displayed two bands, and peptide mapping data strongly suggest that besides hAID-FL, the lower band showed a significant number of amino acids missing towards the C-terminal domain (named as hAIDδC). Our results are the first report to show that expression of recombinant hAID alone or irrespective of solubilization tags in E. coli cells produced hAID-FL and hAIDδC. It will be fascinating to explore the potential mechanism underlying the expression of hAIDδC from recombinant hAID plasmid in E. coli cells.
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6
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Sekar G, Stevens AJ, Mostafavi AZ, Sashi P, Muir TW, Cowburn D. A Conserved Histidine Residue Drives Extein Dependence in an Enhanced Atypically Split Intein. J Am Chem Soc 2022; 144:19196-19203. [PMID: 36194550 PMCID: PMC10241006 DOI: 10.1021/jacs.2c08985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Split intein-mediated protein trans-splicing (PTS) is widely applied in chemical biology and biotechnology to carry out traceless and specific protein ligation. However, the external residues immediately flanking the intein (exteins) can reduce the splicing rate, thereby limiting certain applications of PTS. Splicing by a recently developed intein with atypical split architecture ("Cat") exhibits a stark dependence on the sequence of its N-terminal extein residues. Here, we further developed Cat using error-prone polymerase chain reaction (PCR) and a cell-based selection assay to produce Cat*, which exhibits greatly enhanced PTS activity in the presence of unfavorable N-extein residues. We then applied solution nuclear magnetic resonance spectroscopy and molecular dynamics simulations to explore how the dynamics of a conserved B-block histidine residue (His78) contribute to this extein dependence. The enhanced extein tolerance of Cat* reported here should expand the applicability of atypically split inteins, and the mechanism highlights common principles that contribute to extein dependence.
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Affiliation(s)
- Giridhar Sekar
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Adam J. Stevens
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, USA
| | - Anahita Z. Mostafavi
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, USA
| | - Pulikallu Sashi
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, USA
| | - David Cowburn
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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7
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Allemann RK, Samperio R, Mart R, Luk L, Tsai YH, Jones A, Cruz-Samperio R. Spatio-temporal control of cell death by selective delivery of photo-activatable proteins. Chembiochem 2022; 23:e202200115. [PMID: 35420232 PMCID: PMC9321962 DOI: 10.1002/cbic.202200115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/10/2022] [Indexed: 11/24/2022]
Abstract
Protein therapeutics offer exquisite selectivity in targeting cellular processes and behaviors, but are rarely used against non‐cell surface targets due to their poor cellular uptake. While cell‐penetrating peptides can be used to deliver recombinant proteins to the cytosol, it is generally difficult to selectively deliver active proteins to target cells. Here, we report a recombinantly produced, intracellular protein delivery and targeting platform that uses a photocaged intein to regulate the spatio‐temporal activation of protein activity in selected cells upon irradiation with light. The platform was successfully demonstrated for two cytotoxic proteins to selectively kill cancer cells after photoactivation of intein splicing. This platform can generically be applied to any protein whose activity can be disrupted by a fused intein, allowing it to underpin a wide variety of future protein therapeutics.
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Affiliation(s)
- Rudolf K Allemann
- Cardiff University, School of Chemistry, Main Building, Park Place, CF10 3AT, Cardiff, UNITED KINGDOM
| | - Raquel Samperio
- Cardiff University, Chemistry, SchooCardiff University, Main Building, Park Place, CF10 3AT, Cardiff, UNITED KINGDOM
| | - Robert Mart
- Cardiff University, Chemistry, UNITED KINGDOM
| | - Louis Luk
- Cardiff University, Chemistry, UNITED KINGDOM
| | | | - Arwyn Jones
- Cardiff University, School of Pharmacy and Pharmaceutical Sciences, UNITED KINGDOM
| | - Raquel Cruz-Samperio
- University of Bristol School of Cellular and Molecular Medicine, School of Cellular and Molecular Medicine, UNITED KINGDOM
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8
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Wall DA, Tarrant SP, Wang C, Mills KV, Lennon CW. Intein Inhibitors as Novel Antimicrobials: Protein Splicing in Human Pathogens, Screening Methods, and Off-Target Considerations. Front Mol Biosci 2021; 8:752824. [PMID: 34692773 PMCID: PMC8529194 DOI: 10.3389/fmolb.2021.752824] [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: 08/03/2021] [Accepted: 09/24/2021] [Indexed: 01/20/2023] Open
Abstract
Protein splicing is a post-translational process by which an intervening polypeptide, or intein, catalyzes its own removal from the flanking polypeptides, or exteins, concomitant with extein ligation. Although inteins are highly abundant in the microbial world, including within several human pathogens, they are absent in the genomes of metazoans. As protein splicing is required to permit function of essential proteins within pathogens, inteins represent attractive antimicrobial targets. Here we review key proteins interrupted by inteins in pathogenic mycobacteria and fungi, exciting discoveries that provide proof of concept that intein activity can be inhibited and that this inhibition has an effect on the host organism's fitness, and bioanalytical methods that have been used to screen for intein activity. We also consider potential off-target inhibition of hedgehog signaling, given the similarity in structure and function of inteins and hedgehog autoprocessing domains.
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Affiliation(s)
- Diana A Wall
- Department of Chemistry, College of the Holy Cross, Worcester, MA, United States
| | - Seanan P Tarrant
- Department of Chemistry, College of the Holy Cross, Worcester, MA, United States
| | - Chunyu Wang
- Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States.,Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, Worcester, MA, United States
| | - Christopher W Lennon
- Department of Biological Sciences, Murray State University, Murray, KY, United States
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Woods D, LeSassier DS, Egbunam I, Lennon CW. Construction and Quantitation of a Selectable Protein Splicing Sensor Using Gibson Assembly and Spot Titers. Curr Protoc 2021; 1:e82. [PMID: 33739627 DOI: 10.1002/cpz1.82] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Inteins (intervening proteins) are translated within host proteins and removed through protein splicing. Conditional protein splicing (CPS), where the rate and accuracy of splicing are highly dependent on environmental cues, has emerged as a novel form of post-translational regulation. While CPS has been demonstrated for several inteins in vitro, a comprehensive understanding of inteins requires tools to quantitatively monitor their activity within the cellular context. Here, we describe a method for construction of a splicing-dependent system that can be used to quantitatively assay for conditions that modulate protein splicing. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Construction of an intein-containing KanR2 library using Gibson assembly Basic Protocol 2: Phenotype determination using quantitative spot titers Support Protocol 1: Preparation of LB agar plates for spot titers Support Protocol 2: Preparation and transformation of competent M. smegmatis cells.
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Affiliation(s)
- Daniel Woods
- Wadsworth Center, New York State Department of Health, Albany, New York
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10
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Park J, Lee S, Kim Y, Yoo TH. Methods to generate site-specific conjugates of antibody and protein. Bioorg Med Chem 2021; 30:115946. [DOI: 10.1016/j.bmc.2020.115946] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
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11
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Oeemig JS, Beyer HM, Aranko AS, Mutanen J, Iwaï H. Substrate specificities of inteins investigated by QuickDrop-cassette mutagenesis. FEBS Lett 2020; 594:3338-3355. [PMID: 32805768 DOI: 10.1002/1873-3468.13909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/05/2020] [Accepted: 08/10/2020] [Indexed: 01/21/2023]
Abstract
Inteins catalyze self-excision from host precursor proteins while concomitantly ligating the flanking substrates (exteins) with a peptide bond. Noncatalytic extein residues near the splice junctions, such as the residues at the -1 and +2 positions, often strongly influence the protein-splicing efficiency. The substrate specificities of inteins have not been studied for many inteins. We developed a convenient mutagenesis platform termed "QuickDrop"-cassette mutagenesis for investigating the influences of 20 amino acid types at the -1 and +2 positions of different inteins. We elucidated 17 different profiles of the 20 amino acid dependencies across different inteins. The substrate specificities will accelerate our understanding of the structure-function relationship at the splicing junctions for broader applications of inteins in biotechnology and molecular biosciences.
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Affiliation(s)
- Jesper S Oeemig
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hannes M Beyer
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - A Sesilja Aranko
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Justus Mutanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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12
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Woods D, Vangaveti S, Egbanum I, Sweeney AM, Li Z, Bacot-Davis V, LeSassier DS, Stanger M, Hardison GE, Li H, Belfort M, Lennon CW. Conditional DnaB Protein Splicing Is Reversibly Inhibited by Zinc in Mycobacteria. mBio 2020; 11:e01403-20. [PMID: 32665276 PMCID: PMC7360933 DOI: 10.1128/mbio.01403-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 06/09/2020] [Indexed: 11/20/2022] Open
Abstract
Inteins, as posttranslational regulatory elements, can tune protein function to environmental changes by conditional protein splicing (CPS). Translated as subdomains interrupting host proteins, inteins splice to scarlessly join flanking sequences (exteins). We used DnaB-intein1 (DnaBi1) from a replicative helicase of Mycobacterium smegmatis to build a kanamycin intein splicing reporter (KISR) that links splicing of DnaBi1 to kanamycin resistance. Using expression in heterologous Escherichia coli, we observed phenotypic classes of various levels of splicing-dependent resistance (SDR) and related these to the insertion position of DnaBi1 within the kanamycin resistance protein (KanR). The KanR-DnaBi1 construct demonstrating the most stringent SDR was used to probe for CPS of DnaB in the native host environment, M. smegmatis We show here that zinc, important during mycobacterial pathogenesis, inhibits DnaB splicing in M. smegmatis Using an in vitro reporter system, we demonstrated that zinc potently and reversibly inhibited DnaBi1 splicing, as well as splicing of a comparable intein from Mycobacterium leprae Finally, in a 1.95 Å crystal structure, we show that zinc inhibits splicing through binding to the very cysteine that initiates the splicing reaction. Together, our results provide compelling support for a model whereby mycobacterial DnaB protein splicing, and thus DNA replication, is responsive to environmental zinc.IMPORTANCE Inteins are present in a large fraction of prokaryotes and localize within conserved proteins, including the mycobacterial replicative helicase DnaB. In addition to their extensive protein engineering applications, inteins have emerged as environmentally responsive posttranslational regulators of the genes that encode them. While several studies have shown compelling evidence of conditional protein splicing (CPS), examination of splicing in the native host of the intein has proven to be challenging. Here, we demonstrated through a number of measures, including the use of a splicing-dependent sensor capable of monitoring intein activity in the native host, that zinc is a potent and reversible inhibitor of mycobacterial DnaB splicing. This work also expands our knowledge of site selection for intein insertion within nonnative proteins, demonstrating that splicing-dependent host protein activation correlates with proximity to the active site. Additionally, we surmise that splicing regulation by zinc has mycobacteriocidal and CPS application potential.
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Affiliation(s)
- Daniel Woods
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | - Sweta Vangaveti
- The RNA Institute, University at Albany, Albany, New York, USA
| | - Ikechukwu Egbanum
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | - Allison M Sweeney
- Department of Biology, Murray State University, Murray, Kentucky, USA
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Valjean Bacot-Davis
- Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | | | - Matthew Stanger
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | | | - Hongmin Li
- Department of Biological Sciences, University at Albany, Albany, New York, USA
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Marlene Belfort
- Department of Biological Sciences, University at Albany, Albany, New York, USA
- The RNA Institute, University at Albany, Albany, New York, USA
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13
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Khoo ATT, Kim PJ, Kim HM, Je HS. Neural circuit analysis using a novel intersectional split intein-mediated split-Cre recombinase system. Mol Brain 2020; 13:101. [PMID: 32616061 PMCID: PMC7331137 DOI: 10.1186/s13041-020-00640-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/23/2020] [Indexed: 11/10/2022] Open
Abstract
The defining features of a neuron are its functional and anatomical connections with thousands of other neurons in the brain. Together, these neurons form functional networks that direct animal behavior. Current approaches that allow the interrogation of specific populations of neurons and neural circuits rely heavily on targeting their gene expression profiles or connectivity. However, these approaches are often unable to delineate specific neuronal populations. Here, we developed a novel intersectional split intein-mediated split-Cre recombinase system that can selectively label specific types of neurons based on their gene expression profiles and structural connectivity. We developed this system by splitting Cre recombinase into two fragments with evolved split inteins and subsequently expressed one fragment under the influence of a cell type-specific promoter in a transgenic animal, and delivered the other fragment via retrograde viral gene transfer. This approach results in the reconstitution of Cre recombinase in only specific population of neurons projecting from a specific brain region or in those of a specific neuronal type. Taken together, our split intein-based split-Cre system will be useful for sophisticated characterization of mammalian brain circuits.
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Affiliation(s)
- Audrey Tze Ting Khoo
- Neuroscience and Behavioural Disorders Programme, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Paul Jong Kim
- Neuroscience and Behavioural Disorders Programme, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Ho Min Kim
- Graduate School of Medical Science & Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea.,Center for Biomolecular & Cellular Structure, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - H Shawn Je
- Neuroscience and Behavioural Disorders Programme, Duke-National University of Singapore (NUS) Medical School, 8 College Road, Singapore, 169857, Singapore.
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14
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Abstract
Split inteins are privileged molecular scaffolds for the chemical modification of proteins. Though efficient for in vitro applications, these polypeptide ligases have not been utilized for the semisynthesis of proteins in live cells. Here, we biochemically and structurally characterize the naturally split intein VidaL. We show that this split intein, which features the shortest known N-terminal fragment, supports rapid and efficient protein trans-splicing under a range of conditions, enabling semisynthesis of modified proteins both in vitro and in mammalian cells. The utility of this protein engineering system is illustrated through the traceless assembly of multidomain proteins whose biophysical properties render them incompatible with a single expression system, as well as by the semisynthesis of dual posttranslationally modified histone proteins in live cells. We also exploit the domain swapping function of VidaL to effect simultaneous modification and translocation of the nuclear protein HP1α in live cells. Collectively, our studies highlight the VidaL system as a tool for the precise chemical modification of cellular proteins with spatial and temporal control.
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15
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Seo HN, Bang D. Promiscuous Trans-splicing Activities Revealed by Next Generation Sequencing-based Analysis of 298 Split Inteins. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Abstract
Protein semisynthesis-defined herein as the assembly of a protein from a combination of synthetic and recombinant fragments-is a burgeoning field of chemical biology that has impacted many areas in the life sciences. In this review, we provide a comprehensive survey of this area. We begin by discussing the various chemical and enzymatic methods now available for the manufacture of custom proteins containing noncoded elements. This section begins with a discussion of methods that are more chemical in origin and ends with those that employ biocatalysts. We also illustrate the commonalities that exist between these seemingly disparate methods and show how this is allowing for the development of integrated chemoenzymatic methods. This methodology discussion provides the technical foundation for the second part of the review where we cover the great many biological problems that have now been addressed using these tools. Finally, we end the piece with a short discussion on the frontiers of the field and the opportunities available for the future.
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Affiliation(s)
| | - Tom W. Muir
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, New Jersey 08544, United States
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17
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Ciragan A, Backlund SM, Mikula KM, Beyer HM, Samuli Ollila OH, Iwaï H. NMR Structure and Dynamics of TonB Investigated by Scar-Less Segmental Isotopic Labeling Using a Salt-Inducible Split Intein. Front Chem 2020; 8:136. [PMID: 32266203 PMCID: PMC7098700 DOI: 10.3389/fchem.2020.00136] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/13/2020] [Indexed: 11/22/2022] Open
Abstract
The growing understanding of partially unfolded proteins increasingly points to their biological relevance in allosteric regulation, complex formation, and protein design. However, the structural characterization of disordered proteins remains challenging. NMR methods can access both the dynamics and structures of such proteins, yet suffering from a high degeneracy of NMR signals. Here, we overcame this bottleneck utilizing a salt-inducible split intein to produce segmentally isotope-labeled samples with the native sequence, including the ligation junction. With this technique, we investigated the NMR structure and conformational dynamics of TonB from Helicobacter pylori in the presence of a proline-rich low complexity region. Spin relaxation experiments suggest that the several nano-second time scale dynamics of the C-terminal domain (CTD) is almost independent of the faster pico-to-nanosecond dynamics of the low complexity central region (LCCR). Our results demonstrate the utility of segmental isotopic labeling for proteins with heterogenous dynamics such as TonB and could advance NMR studies of other partially unfolded proteins.
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Affiliation(s)
- Annika Ciragan
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Sofia M Backlund
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Kornelia M Mikula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hannes M Beyer
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - O H Samuli Ollila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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18
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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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19
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Abstract
In recent years, split inteins have seen widespread use as molecular platforms for the design of a variety of peptide and protein chemistry technologies, most notably protein ligation. The development of these approaches is dependent on the identification and/or design of split inteins with robust activity, stability, and solubility. Here, we describe two approaches to characterize and compare the activities of newly identified or engineered split inteins. The first assay employs an E. coli-based selection system to rapidly screen the activities of many inteins and can be repurposed for directed evolution. The second assay utilizes reverse-phase high-performance liquid chromatography (RP-HPLC) to provide insights into individual chemical steps in the protein splicing reaction, information that can guide further engineering efforts. These techniques provide useful alternatives to common assays that utilize SDS-PAGE to analyze splicing reaction progress.
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20
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Tornabene P, Trapani I. Can Adeno-Associated Viral Vectors Deliver Effectively Large Genes? Hum Gene Ther 2020; 31:47-56. [DOI: 10.1089/hum.2019.220] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Patrizia Tornabene
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy
| | - Ivana Trapani
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
- Medical Genetics, Department of Translational Medicine, Federico II University, Naples, Italy
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21
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Olorunniji FJ, Lawson-Williams M, McPherson AL, Paget JE, Stark WM, Rosser SJ. Control of ϕC31 integrase-mediated site-specific recombination by protein trans-splicing. Nucleic Acids Res 2019; 47:11452-11460. [PMID: 31667500 PMCID: PMC6868429 DOI: 10.1093/nar/gkz936] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 09/30/2019] [Accepted: 10/07/2019] [Indexed: 11/13/2022] Open
Abstract
Serine integrases are emerging as core tools in synthetic biology and have applications in biotechnology and genome engineering. We have designed a split-intein serine integrase-based system with potential for regulation of site-specific recombination events at the protein level in vivo. The ϕC31 integrase was split into two extein domains, and intein sequences (Npu DnaEN and Ssp DnaEC) were attached to the two termini to be fused. Expression of these two components followed by post-translational protein trans-splicing in Escherichia coli generated a fully functional ϕC31 integrase. We showed that protein splicing is necessary for recombination activity; deletion of intein domains or mutation of key intein residues inactivated recombination. We used an invertible promoter reporter system to demonstrate a potential application of the split intein-regulated site-specific recombination system in building reversible genetic switches. We used the same split inteins to control the reconstitution of a split Integrase-Recombination Directionality Factor fusion (Integrase-RDF) that efficiently catalysed the reverse attR x attL recombination. This demonstrates the potential for split-intein regulation of the forward and reverse reactions using the integrase and the integrase-RDF fusion, respectively. The split-intein integrase is a potentially versatile, regulatable component for building synthetic genetic circuits and devices.
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Affiliation(s)
- Femi J Olorunniji
- School of Pharmacy and Biomolecular Sciences, Faculty of Science, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, UK
| | - Makeba Lawson-Williams
- School of Pharmacy and Biomolecular Sciences, Faculty of Science, Liverpool John Moores University, James Parsons Building, Byrom Street, Liverpool L3 3AF, UK
| | - Arlene L McPherson
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| | - Jane E Paget
- UK Centre for Mammalian Synthetic Biology at the Institute of Quantitative Biology, Biochemistry, and Biotechnology, SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JD, UK.,Institute for Bioengineering, University of Edinburgh, Faraday Building, The King's Buildings, Edinburgh, 2 EH9 3DW, UK
| | - W Marshall Stark
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Bower Building, Glasgow G12 8QQ, UK
| | - Susan J Rosser
- UK Centre for Mammalian Synthetic Biology at the Institute of Quantitative Biology, Biochemistry, and Biotechnology, SynthSys, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JD, UK.,Institute for Bioengineering, University of Edinburgh, Faraday Building, The King's Buildings, Edinburgh, 2 EH9 3DW, UK
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22
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Gale GAR, Schiavon Osorio AA, Mills LA, Wang B, Lea-Smith DJ, McCormick AJ. Emerging Species and Genome Editing Tools: Future Prospects in Cyanobacterial Synthetic Biology. Microorganisms 2019; 7:E409. [PMID: 31569579 PMCID: PMC6843473 DOI: 10.3390/microorganisms7100409] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/22/2019] [Accepted: 09/24/2019] [Indexed: 12/19/2022] Open
Abstract
Recent advances in synthetic biology and an emerging algal biotechnology market have spurred a prolific increase in the availability of molecular tools for cyanobacterial research. Nevertheless, work to date has focused primarily on only a small subset of model species, which arguably limits fundamental discovery and applied research towards wider commercialisation. Here, we review the requirements for uptake of new strains, including several recently characterised fast-growing species and promising non-model species. Furthermore, we discuss the potential applications of new techniques available for transformation, genetic engineering and regulation, including an up-to-date appraisal of current Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein (CRISPR/Cas) and CRISPR interference (CRISPRi) research in cyanobacteria. We also provide an overview of several exciting molecular tools that could be ported to cyanobacteria for more advanced metabolic engineering approaches (e.g., genetic circuit design). Lastly, we introduce a forthcoming mutant library for the model species Synechocystis sp. PCC 6803 that promises to provide a further powerful resource for the cyanobacterial research community.
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Affiliation(s)
- Grant A R Gale
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
| | - Alejandra A Schiavon Osorio
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
| | - Lauren A Mills
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Baojun Wang
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FF, UK.
| | - David J Lea-Smith
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Alistair J McCormick
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3BF, UK.
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23
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Thompson RE, Stevens AJ, Muir TW. Protein engineering through tandem transamidation. Nat Chem 2019; 11:737-743. [PMID: 31263208 PMCID: PMC6711197 DOI: 10.1038/s41557-019-0281-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/10/2019] [Indexed: 01/01/2023]
Abstract
Semisynthetic proteins engineered to contain non-coded elements such as post-translational modifications (PTMs) represent a powerful class of tools for interrogating biological processes. Here, we introduce a one-pot, chemoenzymatic method that allows broad access to chemically modified proteins. The approach involves a tandem transamidation reaction cascade that integrates intein-mediated protein splicing with enzyme-mediated peptide ligation. We show that this approach can be used to introduce PTMs and biochemical probes into a range of proteins including Cas9 nuclease and the transcriptional regulator MeCP2, which causes Rett syndrome when mutated. The versatility of the approach is further illustrated through the chemical tailoring of histone proteins within a native chromatin setting. We expect our approach will extend the scope of semisynthesis in protein engineering.
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Affiliation(s)
- Robert E Thompson
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Princeton, NJ, USA
| | - Adam J Stevens
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Princeton, NJ, USA
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Tom W Muir
- Department of Chemistry, Princeton University, Frick Chemistry Laboratory, Princeton, NJ, USA.
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24
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Beyer HM, Iwaï H. Off-Pathway-Sensitive Protein-Splicing Screening Based on a Toxin/Antitoxin System. Chembiochem 2019; 20:1933-1938. [PMID: 30963690 PMCID: PMC6771659 DOI: 10.1002/cbic.201900139] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Indexed: 02/04/2023]
Abstract
Protein‐splicing domains are frequently used engineering tools that find application in the in vivo and in vitro ligation of protein domains. Directed evolution is among the most promising technologies used to advance this technology. However, the available screening systems for protein‐splicing activity are associated with bottlenecks such as the selection of pseudo‐positive clones arising from off‐pathway reaction products or fragment complementation. Herein, we report a stringent screening method for protein‐splicing activity in cis and trans, that exclusively selects productively splicing domains. By fusing splicing domains to an intrinsically disordered region of the antidote from the Escherichia coli CcdA/CcdB type II toxin/antitoxin system, we linked protein splicing to cell survival. The screen allows selecting novel cis‐ and trans‐splicing inteins catalyzing productive highly efficient protein splicing, for example, from directed‐evolution approaches or the natural intein sequence space.
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Affiliation(s)
- Hannes M Beyer
- Research Program in Structural Biology and Biophysics, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
| | - Hideo Iwaï
- Research Program in Structural Biology and Biophysics, University of Helsinki, Viikinkaari 1, 00014, Helsinki, Finland
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25
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Kelley DS, Lennon CW, Li Z, Miller MR, Banavali NK, Li H, Belfort M. Mycobacterial DnaB helicase intein as oxidative stress sensor. Nat Commun 2018; 9:4363. [PMID: 30341292 PMCID: PMC6195587 DOI: 10.1038/s41467-018-06554-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 09/10/2018] [Indexed: 11/09/2022] Open
Abstract
Inteins are widespread self-splicing protein elements emerging as potential post-translational environmental sensors. Here, we describe two inteins within one protein, the Mycobacterium smegmatis replicative helicase DnaB. These inteins, DnaBi1 and DnaBi2, have homology to inteins in pathogens, splice with vastly varied rates, and are differentially responsive to environmental stressors. Whereas DnaBi1 splicing is reversibly inhibited by oxidative and nitrosative insults, DnaBi2 is not. Using a reporter that measures splicing in a native intein-containing organism and western blotting, we show that H2O2 inhibits DnaBi1 splicing in M. smegmatis. Intriguingly, upon oxidation, the catalytic cysteine of DnaBi1 forms an intramolecular disulfide bond. We report a crystal structure of the class 3 DnaBi1 intein at 1.95 Å, supporting our findings and providing insight into this splicing mechanism. We propose that this cysteine toggle allows DnaBi1 to sense stress, pausing replication to maintain genome integrity, and then allowing splicing immediately when permissive conditions return.
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Affiliation(s)
- Danielle S Kelley
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA
| | - Christopher W Lennon
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY, 12222, USA
| | - Zhong Li
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208, USA
| | - Michael R Miller
- Department of Chemistry, University at Albany, Albany, NY, 12222, USA
| | - Nilesh K Banavali
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208, USA
| | - Hongmin Li
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA.
- Wadsworth Center, New York State Department of Health, 120 New Scotland Ave, Albany, NY, 12208, USA.
| | - Marlene Belfort
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12222, USA.
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY, 12222, USA.
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26
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Matern JCJ, Friedel K, Binschik J, Becher KS, Yilmaz Z, Mootz HD. Altered Coordination of Individual Catalytic Steps in Different and Evolved Inteins Reveals Kinetic Plasticity of the Protein Splicing Pathway. J Am Chem Soc 2018; 140:11267-11275. [PMID: 30111090 DOI: 10.1021/jacs.8b04794] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Protein splicing performed by inteins provides powerful opportunities to manipulate protein structure and function, however, detailed mechanistic knowledge of the multistep pathway to help engineering optimized inteins remains scarce. A typical intein has to coordinate three steps to maximize the product yield of ligated exteins. We have revealed a new type of coordination in the Ssp DnaB intein, in which the initial N- S acyl shift appears rate-limiting and acts as an up-regulation switch to dramatically accelerate the last step of succinimide formation, which is thus coupled to the first step. The structure-activity relationship at the N-terminal scissile bond was studied with atomic precision using a semisynthetic split intein. We show that the removal of the extein acyl group from the α-amino moiety of the intein's first residue is strictly required and sufficient for the up-regulation switch. Even an acetyl group as the smallest possible extein moiety completely blocked the switch. Furthermore, we investigated the M86 intein, a mutant with faster splicing kinetics previously obtained by laboratory evolution of the Ssp DnaB intein, and the individual impact of its eight mutations. The succinimide formation was decoupled from the first step in the M86 intein, but the acquired H143R mutation acts as a brake to prevent premature C-terminal cleavage and thereby maximizes splicing yields. Together, these results revealed a high degree of plasticity in the kinetic coordination of the splicing pathway. Furthermore, our study led to the rational design of improved M86 mutants with the highest yielding trans-splicing and fastest trans-cleavage activities.
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Affiliation(s)
- Julian C J Matern
- Institute of Biochemistry, Department of Chemistry and Pharmacy , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany
| | - Kristina Friedel
- Institute of Biochemistry, Department of Chemistry and Pharmacy , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany
| | - Jens Binschik
- Institute of Biochemistry, Department of Chemistry and Pharmacy , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany
| | - Kira-Sophie Becher
- Institute of Biochemistry, Department of Chemistry and Pharmacy , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany
| | - Zahide Yilmaz
- Institute of Biochemistry, Department of Chemistry and Pharmacy , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany
| | - Henning D Mootz
- Institute of Biochemistry, Department of Chemistry and Pharmacy , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany
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27
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Xu Y, Zhang L, Ma B, Hu L, Lu H, Dou T, Chen J, Zhu J. Intermolecular disulfide bonds between unpaired cysteines retard the C-terminal trans-cleavage of Npu DnaE. Enzyme Microb Technol 2018; 118:6-12. [PMID: 30143201 DOI: 10.1016/j.enzmictec.2018.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 06/15/2018] [Accepted: 06/27/2018] [Indexed: 10/28/2022]
Abstract
Npu DnaE is a naturally occurred split intein possessing robust trans-splicing activity and could be engineered to perform rapid C-terminal cleavage module by a single mutation D118G. Unfortunately, however, for this modified selfcleaving module, reducing agents were needed to trigger the rapid cleavage, which prevents the utilization in purification of disulfide bonds containing recombinant proteins. In this study, we demonstrated that the unpaired cysteine residues in Npu DnaE tend to form disulfide bonds, and contributed to the reduction of the cleavage under non-reducing conditions. This redox trap can be disrupted by site-directed mutation of these unpaired cysteines. The results further indicated that the position 28 and 59 may play certain roles in the correct folding of the active conformation.
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Affiliation(s)
- Yanran Xu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lei Zhang
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation Program, National Cancer Institute, Frederick, MD, 21702, USA
| | - Lifu Hu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Huili Lu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tonglu Dou
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junsheng Chen
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Jianwei Zhu
- Engineering Research Center of Cell and Therapeutic Antibody, Ministry of Education, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; Jecho Laboratories, Inc., Frederick, MD, USA.
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28
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Ye B, Shen W, Shi M, Zhang Y, Xu C, Zhao Z. Intein-mediated backbone cyclization of entolimod confers enhanced radioprotective activity in mouse models. PeerJ 2018; 6:e5043. [PMID: 29938138 PMCID: PMC6011820 DOI: 10.7717/peerj.5043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 05/31/2018] [Indexed: 12/03/2022] Open
Abstract
Background Entolimod is a Salmonella enterica flagellin derivate. Previous work has demonstrated that entolimod effectively protects mice and non-human primates from ionizing radiation. However, it caused a “flu-like” syndrome after radioprotective and anticancer clinical application, indicating some type of immunogenicity and toxicity. Cyclization is commonly used to improve the in vivo stability and activity of peptides and proteins. Methods We designed and constructed cyclic entolimod using split Nostoc punctiforme DnaE intein with almost 100% cyclization efficiency. We adopted different strategies to purify the linear and circular entolimod due to their different topologies. Both of linear and circular entolimod were first purified by Ni-chelating affinity chromatography, and then the linear and circular entolimod were purified by size-exclusion and ion-exchange chromatography, respectively. Results The circular entolimod showed significantly increased both the in vitro NF-κB signaling and in vivo radioprotective activity in mice. Conclusion Our data indicates that circular entolimod might be a good candidate for further clinical investigation.
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Affiliation(s)
- Bingyu Ye
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, College of Life Science, Henan Normal University, Xinxiang, China.,Beijing Institute of Biotechnology, Beijing, China
| | - Wenlong Shen
- Beijing Institute of Biotechnology, Beijing, China
| | - Minglei Shi
- Beijing Institute of Biotechnology, Beijing, China
| | - Yan Zhang
- Beijing Institute of Biotechnology, Beijing, China
| | - Cunshuan Xu
- College of Life Science, Henan Normal University, Xinxiang, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation, College of Life Science, Henan Normal University, Xinxiang, China
| | - Zhihu Zhao
- Beijing Institute of Biotechnology, Beijing, China
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29
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Gramespacher JA, Stevens AJ, Thompson RE, Muir TW. Improved protein splicing using embedded split inteins. Protein Sci 2018; 27:614-619. [PMID: 29226478 PMCID: PMC5818749 DOI: 10.1002/pro.3357] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 12/01/2017] [Indexed: 01/24/2023]
Abstract
Naturally split inteins mediate a traceless protein ligation process known as protein trans-splicing (PTS). Although frequently used in protein engineering applications, the efficiency of PTS can be reduced by the tendency of some split intein fusion constructs to aggregate; a consequence of the fragmented nature of the split intein itself or the polypeptide to which it is fused (the extein). Here, we report a strategy to help address this liability. This involves embedding the split intein within a protein sequence designed to stabilize either the intein fragment itself or the appended extein. We expect this approach to increase the scope of PTS-based protein engineering efforts.
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Affiliation(s)
| | - Adam J. Stevens
- Department of ChemistryPrinceton University, Frick Laboratory, PrincetonNew Jersey
| | - Robert E. Thompson
- Department of ChemistryPrinceton University, Frick Laboratory, PrincetonNew Jersey
| | - Tom W. Muir
- Department of ChemistryPrinceton University, Frick Laboratory, PrincetonNew Jersey
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30
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Gupta S, Tycko R. Segmental isotopic labeling of HIV-1 capsid protein assemblies for solid state NMR. JOURNAL OF BIOMOLECULAR NMR 2018; 70:103-114. [PMID: 29464399 PMCID: PMC5832360 DOI: 10.1007/s10858-017-0162-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/28/2017] [Indexed: 05/09/2023]
Abstract
Recent studies of noncrystalline HIV-1 capsid protein (CA) assemblies by our laboratory and by Polenova and coworkers (Protein Sci 19:716-730, 2010; J Mol Biol 426:1109-1127, 2014; J Biol Chem 291:13098-13112, 2016; J Am Chem Soc 138:8538-8546, 2016; J Am Chem Soc 138:12029-12032, 2016; J Am Chem Soc 134:6455-6466, 2012; J Am Chem Soc 132:1976-1987, 2010; J Am Chem Soc 135:17793-17803, 2013; Proc Natl Acad Sci USA 112:14617-14622, 2015; J Am Chem Soc 138:14066-14075, 2016) have established the capability of solid state nuclear magnetic resonance (NMR) measurements to provide site-specific structural and dynamical information that is not available from other types of measurements. Nonetheless, the relatively high molecular weight of HIV-1 CA leads to congestion of solid state NMR spectra of fully isotopically labeled assemblies that has been an impediment to further progress. Here we describe an efficient protocol for production of segmentally labeled HIV-1 CA samples in which either the N-terminal domain (NTD) or the C-terminal domain (CTD) is uniformly 15N,13C-labeled. Segmental labeling is achieved by trans-splicing, using the DnaE split intein. Comparisons of two-dimensional solid state NMR spectra of fully labeled and segmentally labeled tubular CA assemblies show substantial improvements in spectral resolution. The molecular structure of HIV-1 assemblies is not significantly perturbed by the single Ser-to-Cys substitution that we introduce between NTD and CTD segments, as required for trans-splicing.
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Affiliation(s)
- Sebanti Gupta
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
- National Institutes of Health, Building 5, Room 409, Bethesda, MD, 20892-0520, USA.
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31
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Kick LM, Harteis S, Koch MF, Schneider S. Mechanistic Insights into Cyclic Peptide Generation by DnaE Split-Inteins through Quantitative and Structural Investigation. Chembiochem 2017; 18:2242-2246. [DOI: 10.1002/cbic.201700503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Leonhard M. Kick
- Center for Integrated Protein Science; Department of Chemistry; Technische Universität München; Lichtenbergstrasse 4 85748 Garching Germany
| | - Sabrina Harteis
- Center for Integrated Protein Science; Department of Chemistry; Technische Universität München; Lichtenbergstrasse 4 85748 Garching Germany
| | - Maximilian F. Koch
- Center for Integrated Protein Science; Department of Chemistry; Technische Universität München; Lichtenbergstrasse 4 85748 Garching Germany
| | - Sabine Schneider
- Center for Integrated Protein Science; Department of Chemistry; Technische Universität München; Lichtenbergstrasse 4 85748 Garching Germany
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32
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A promiscuous split intein with expanded protein engineering applications. Proc Natl Acad Sci U S A 2017; 114:8538-8543. [PMID: 28739907 DOI: 10.1073/pnas.1701083114] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The protein trans-splicing (PTS) activity of naturally split inteins has found widespread use in chemical biology and biotechnology. However, currently used naturally split inteins suffer from an "extein dependence," whereby residues surrounding the splice junction strongly affect splicing efficiency, limiting the general applicability of many PTS-based methods. To address this, we describe a mechanism-guided protein engineering approach that imbues ultrafast DnaE split inteins with minimal extein dependence. The resulting "promiscuous" inteins are shown to be superior reagents for protein cyclization and protein semisynthesis, with the latter illustrated through the modification of native cellular chromatin. The promiscuous inteins reported here thus improve the applicability of existing PTS methods and should enable future efforts to engineer promiscuity into other naturally split inteins.
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33
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Neugebauer M, Böcker JK, Matern JCJ, Pietrokovski S, Mootz HD. Development of a screening system for inteins active in protein splicing based on intein insertion into the LacZα-peptide. Biol Chem 2017; 398:57-67. [PMID: 27632429 DOI: 10.1515/hsz-2016-0229] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/23/2016] [Indexed: 11/15/2022]
Abstract
Protein splicing by inteins has found diverse applications in biotechnology, protein chemistry and chemical biology. Inteins display a wide range of efficiencies and rates unpredictable from their amino acid sequences. Here, we identified positions T22S and S35 in the LacZα peptide as intein insertion sites that strictly require protein splicing, in contrast to cleavage side-reactions, to allow for complementation of β-galactosidase activity. Both the cis-variant of the M86 mutant of the Ssp DnaB intein and a split form undergoing protein trans-splicing gave rise to formation of blue colonies in the β-galactosidase read-out. Furthermore, we report the two novel, naturally split VidaL T4Lh-1 and VidaL UvsX-2 inteins whose N-terminal fragments consist of only 15 and 16 amino acids, respectively. Initial biochemical characterization with the LacZα host system of these inteins further underlines its utility. Finally, we used the LacZα host system to rapidly identify amino acid substitutions from a small randomized library at the structurally conserved intein position 2 next to the catalytic center, that are tolerated for protein splicing activity of the M86 intein. These findings demonstrate the potential of the system for initial testing and directed evolution of inteins.
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34
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Mistry I, Tavassoli A. Reprogramming the Transcriptional Response to Hypoxia with a Chromosomally Encoded Cyclic Peptide HIF-1 Inhibitor. ACS Synth Biol 2017; 6:518-527. [PMID: 27978620 PMCID: PMC6014682 DOI: 10.1021/acssynbio.6b00219] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Indexed: 01/16/2023]
Abstract
The cellular response to hypoxia is orchestrated by HIF-1, a heterodimeric transcription factor composed of an α and a β subunit that enables cell survival under low oxygen conditions by altering the transcription of over 300 genes. There is significant evidence that inhibition of HIF-1 would be beneficial for cancer therapy. We recently reported a cyclic hexapeptide that inhibits the HIF-1α/HIF-1β protein-protein interaction in vitro and prevents HIF-1-mediated hypoxia-response signaling in cells. This cyclic peptide was identified from a library of 3.2 × 106 members generated using SICLOPPS split-intein mediated protein splicing. With a view to demonstrating the potential for encoding the production of a therapeutic agent in response to a disease marker, we have engineered human cells with an additional chromosomal control circuit that conditionally encodes the production of our cyclic peptide HIF-1 inhibitor. We demonstrate the conditional production of our HIF-1 inhibitor in response to hypoxia, and its inhibitory effect on HIF-1 dimerization and downstream hypoxia-response signaling. These engineered cells are used to illustrate the synthetic lethality of inhibiting HIF-1 dimerization and glycolysis in hypoxic cells. Our approach not only eliminates the need for the chemical synthesis and targeted delivery of our HIF-1 inhibitor to cells, it also demonstrates the wider possibility that the production machinery of other bioactive compounds may be incorporated onto the chromosome of human cells. This work demonstrates the potential of sentinel circuits that produce molecular modulators of cellular pathways in response to environmental or cellular disease stimuli.
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Affiliation(s)
- Ishna
N. Mistry
- Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K.
| | - Ali Tavassoli
- Chemistry, University of Southampton, Southampton, SO17 1BJ, U.K.
- Institute
for Life Sciences, University of Southampton, Southampton, SO17 1BJ, U.K.
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35
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Budiardjo SJ, Licknack TJ, Cory MB, Kapros D, Roy A, Lovell S, Douglas J, Karanicolas J. Full and Partial Agonism of a Designed Enzyme Switch. ACS Synth Biol 2016; 5:1475-1484. [PMID: 27389009 DOI: 10.1021/acssynbio.6b00097] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chemical biology has long sought to build protein switches for use in molecular diagnostics, imaging, and synthetic biology. The overarching challenge for any type of engineered protein switch is the ability to respond in a selective and predictable manner that caters to the specific environments and time scales needed for the application at hand. We previously described a general method to design switchable proteins, called "chemical rescue of structure", that builds de novo allosteric control sites directly into a protein's functional domain. This approach entails first carving out a buried cavity in a protein via mutation, such that the protein's structure is disrupted and activity is lost. An exogenous ligand is subsequently added to substitute for the atoms that were removed by mutation, restoring the protein's structure and thus its activity. Here, we begin to ask what principles dictate such switches' response to different activating ligands. Using a redesigned β-glycosidase enzyme as our model system, we find that the designed effector site is quite malleable and can accommodate both larger and smaller ligands, but that optimal rescue comes only from a ligand that perfectly replaces the deleted atoms. Guided by these principles, we then altered the shape of this cavity by using different cavity-forming mutations, and predicted different ligands that would better complement these new cavities. These findings demonstrate how the protein switch's response can be tuned via small changes to the ligand with respect to the binding cavity, and ultimately enabled us to design an improved switch. We anticipate that these insights will help enable the design of future systems that tune other aspects of protein activity, whereby, like evolved protein receptors, remolding the effector site can also adjust additional outputs such as substrate selectivity and activation of downstream signaling pathways.
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Affiliation(s)
- S. Jimmy Budiardjo
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - Timothy J. Licknack
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - Michael B. Cory
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - Dora Kapros
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - Anuradha Roy
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - Scott Lovell
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - Justin Douglas
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
| | - John Karanicolas
- Center for Computational Biology, ‡Department of Molecular
Biosciences, §High Throughput Screening
Laboratory, ∥Protein Structure Laboratory, ⊥Molecular Structures Group The University of Kansas, 2030 Becker Drive, Lawrence, Kansas 66045-7534, United States
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36
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Hackl S, Schmid A, Becker CFW. Semisynthesis of Membrane-Attached Proteins Using Split Inteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2016; 1495:93-109. [PMID: 27714612 DOI: 10.1007/978-1-4939-6451-2_7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The site-selective installation of lipid modifications on proteins is critically important in our understanding of how membrane association influences the biophysical properties of proteins as well as to study certain proteins in their native environment. Here, we describe the use of split inteins for the C-terminal attachment of lipid-modified peptides to virtually any protein of interest (POI) via protein trans-splicing (PTS). To achieve this, the protein of interest is expressed in fusion with the N-terminal split intein segment and the C-terminal split intein segment is prepared by solid phase peptide synthesis. A synthetic peptide carrying two lipid chains is also made chemically to serve as a membrane anchor and subsequently linked to the C-terminal split intein by native chemical ligation. Proteins of interest for our work are the prion protein as well as small GTPases; however, extensions to other POIs are possible. Detailed information for the C-terminal introduction of a lipidated membrane anchor (MA) peptide using split intein systems from Synechocystis spp. and Nostoc punctiforme for the Prion protein (PrP, as a challenging protein of interest) and the enhanced green-fluorescent protein (eGFP, as an easily trackable target protein) are provided here.
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Affiliation(s)
- Stefanie Hackl
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria
| | - Alanca Schmid
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria
| | - Christian F W Becker
- Department of Chemistry, Institute of Biological Chemistry, University of Vienna, Waehringer Str. 38, 1090, Vienna, Austria.
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37
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Abstract
Proteins are nature's building blocks and indispensable in living organisms. Protein-based hydrogels have a wide variety of applications in research and biotechnology. In this chapter, we describe an intein-mediated protein hydrogel that utilizes two synthetic soluble protein block copolymers, each containing a subunit of a trimeric protein that serves as a cross-linker and one half of the naturally split DnaE intein from Nostoc punctiforme. Mixing of these two protein block copolymers initiates an intein trans-splicing reaction that constitutes a self-assembling polypeptide flanked by cross-linkers, triggering protein hydrogel formation. The generated hydrogels are highly stable under both acidic and basic conditions, and at temperatures up to 50 °C. In addition, these hydrogels are able to undergo rapid reassembly after shear-induced rupture. Incorporation of an appropriate binding motif into the protein block copolymers enables the convenient site-specific incorporation of functional globular proteins into the hydrogel network.
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38
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Abstract
Split intein circular ligation of peptides and proteins (SICLOPPS) is a genetically encoded method for the intracellular production of cyclic peptide libraries of around 100 million (10(8)) members that utilizes the Synechocystis sp PCC6803 (Ssp) DnaE split inteins. However, Ssp inteins are relatively slow splicing and intolerant of amino acid variation around the splice junction, potentially limiting the utility and composition of SICLOPPS libraries. In contrast, Nostoc punctiforme (Npu) DnaE split inteins not only splice significantly faster, they are also much more tolerant of amino acid variation around their splice junctions. Here, we report the use of engineered Npu inteins in SICLOPPS for the generation of cyclic peptide libraries and cyclic proteins. Despite their superior splicing characteristics, however, we observed a high level of toxicity from the Npu SICLOPPS constructs in E. coli. The observed toxicity was overcome though incorporation of an SsrA tag to target the spliced Npu inteins to the ClpXP complex for degradation. The resulting traceless Npu SICLOPPS inteins showed no toxicity to E. coli, demonstrating their potential for the production of cyclic peptide libraries for use in a variety of high-throughput screens.
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Affiliation(s)
- Jaime E. Townend
- Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
| | - Ali Tavassoli
- Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom
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39
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Jones DC, Mistry IN, Tavassoli A. Post-translational control of protein function with light using a LOV-intein fusion protein. MOLECULAR BIOSYSTEMS 2016; 12:1388-93. [PMID: 26940144 DOI: 10.1039/c6mb00007j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Methods for the post-translational control of protein function with light hold much value as tools in cell biology. To this end, we report a fusion protein that consists of DnaE split-inteins, flanking the light sensitive LOV2 domain of Avena sativa. The resulting chimera combines the activities of these two unrelated proteins to enable controlled formation of a functional protein via upregulation of intein splicing with blue light in bacterial and human cells.
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Affiliation(s)
- D C Jones
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
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40
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Kis Z, Pereira HS, Homma T, Pedrigi RM, Krams R. Mammalian synthetic biology: emerging medical applications. J R Soc Interface 2016; 12:rsif.2014.1000. [PMID: 25808341 DOI: 10.1098/rsif.2014.1000] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In this review, we discuss new emerging medical applications of the rapidly evolving field of mammalian synthetic biology. We start with simple mammalian synthetic biological components and move towards more complex and therapy-oriented gene circuits. A comprehensive list of ON-OFF switches, categorized into transcriptional, post-transcriptional, translational and post-translational, is presented in the first sections. Subsequently, Boolean logic gates, synthetic mammalian oscillators and toggle switches will be described. Several synthetic gene networks are further reviewed in the medical applications section, including cancer therapy gene circuits, immuno-regulatory networks, among others. The final sections focus on the applicability of synthetic gene networks to drug discovery, drug delivery, receptor-activating gene circuits and mammalian biomanufacturing processes.
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Affiliation(s)
- Zoltán Kis
- Department of Bioengineering, Imperial College London, London, UK
| | | | - Takayuki Homma
- Department of Bioengineering, Imperial College London, London, UK
| | - Ryan M Pedrigi
- Department of Bioengineering, Imperial College London, London, UK
| | - Rob Krams
- Department of Bioengineering, Imperial College London, London, UK
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41
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Jung D, Sato K, Min K, Shigenaga A, Jung J, Otaka A, Kwon Y. Photo-triggered fluorescent labelling of recombinant proteins in live cells. Chem Commun (Camb) 2016; 51:9670-3. [PMID: 25977944 DOI: 10.1039/c5cc01067e] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A method to photo-chemically trigger fluorescent labelling of proteins in live cells is developed. The approach is based on photo-caged split-intein mediated conditional protein trans-splicing reaction and enabled background-free fluorescent labelling of target proteins with the necessary spatiotemporal control.
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Affiliation(s)
- Deokho Jung
- Department of Biomedical Engineering, Dongguk University-Seoul, Pildong 3-ga, Seoul, Korea.
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42
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Bachmann AL, Mootz HD. An Unprecedented Combination of Serine and Cysteine Nucleophiles in a Split Intein with an Atypical Split Site. J Biol Chem 2015; 290:28792-804. [PMID: 26453311 DOI: 10.1074/jbc.m115.677237] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Indexed: 11/06/2022] Open
Abstract
Protein splicing mediated by inteins is a self-processive reaction leading to the excision of the internal intein domain from a precursor protein and the concomitant ligation of the flanking sequences, the extein-N and extein-C parts, thereby reconstituting the host protein. Most inteins employ a splicing pathway in which the upstream scissile peptide bond is consecutively rearranged into two thioester or oxoester intermediates before intein excision and rearrangement into the new peptide bond occurs. The catalytically critical amino acids involved at the two splice junctions are cysteine, serine, or threonine. Notably, the only potential combination not observed so far in any of the known or engineered inteins corresponds to the transesterification from an oxoester to a thioester, which suggested that this formal uphill reaction with regard to the thermodynamic stability might be incompatible with intein-mediated catalysis. We show that corresponding mutations also led to inactive gp41-1 and AceL-TerL inteins. We report the novel GOS-TerL split intein identified from metagenomic databases as the first intein harboring the combination of Ser1 and Cys+1 residues. Mutational analysis showed that its efficient splicing reaction indeed follows the shift from oxoester to thioester and thus represents a rare diversion from the canonical pathway. Furthermore, the GOS-TerL intein has an atypical split site close to the N terminus. The Int(N) fragment could be shortened from 37 to 28 amino acids and exchanged with the 25-amino acid Int(N) fragment from the AceL-TerL intein, indicating a high degree of promiscuity of the Int(C) fragment of the GOS-TerL intein.
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Affiliation(s)
- Anne-Lena Bachmann
- From the Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Muenster, 48149 Münster, Germany
| | - Henning D Mootz
- From the Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Muenster, 48149 Münster, Germany
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43
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De novo assembly and next-generation sequencing to analyse full-length gene variants from codon-barcoded libraries. Nat Commun 2015; 6:8351. [PMID: 26387459 PMCID: PMC4595759 DOI: 10.1038/ncomms9351] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 08/12/2015] [Indexed: 12/13/2022] Open
Abstract
Interpreting epistatic interactions is crucial for understanding evolutionary dynamics of complex genetic systems and unveiling structure and function of genetic pathways. Although high resolution mapping of en masse variant libraries renders molecular biologists to address genotype-phenotype relationships, long-read sequencing technology remains indispensable to assess functional relationship between mutations that lie far apart. Here, we introduce JigsawSeq for multiplexed sequence identification of pooled gene variant libraries by combining a codon-based molecular barcoding strategy and de novo assembly of short-read data. We first validate JigsawSeq on small sub-pools and observed high precision and recall at various experimental settings. With extensive simulations, we then apply JigsawSeq to large-scale gene variant libraries to show that our method can be reliably scaled using next-generation sequencing. JigsawSeq may serve as a rapid screening tool for functional genomics and offer the opportunity to explore evolutionary trajectories of protein variants. This paper described a new and efficient method for de novo assembly of multiple DNA sequence information from mutagenized clone libraries. Using codon-barcoded libraries and calling the method JigsawSeq, the authors overcome limitations of short-read sequencing assembly from next-generation sequencing.
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44
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Li Y. Split-inteins and their bioapplications. Biotechnol Lett 2015; 37:2121-37. [DOI: 10.1007/s10529-015-1905-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 06/29/2015] [Indexed: 01/01/2023]
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45
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Abstract
Protein splicing in trans by split inteins has increasingly become a powerful protein-engineering tool for protein ligation, both in vivo and in vitro. Over 100 naturally occurring and artificially engineered split inteins have been reported for protein ligation using protein trans-splicing. Here, we review the current status of the reported split inteins in order to delineate an empirical or rational strategy for constructing new split inteins suitable for various applications in biotechnology and chemical biology.
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Affiliation(s)
- A Sesilja Aranko
- Research Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, National Cancer Institute-Frederick, MD 21702, USA
| | - Hideo Iwaï
- Research Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland
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46
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Ren W, Ji A, Ai HW. Light Activation of Protein Splicing with a Photocaged Fast Intein. J Am Chem Soc 2015; 137:2155-8. [DOI: 10.1021/ja508597d] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Wei Ren
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Ao Ji
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Hui-wang Ai
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, California 92521, United States
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47
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Cheriyan M, Chan SH, Perler F. Traceless splicing enabled by substrate-induced activation of the Nostoc punctiforme Npu DnaE intein after mutation of a catalytic cysteine to serine. J Mol Biol 2014; 426:4018-4029. [PMID: 25451033 DOI: 10.1016/j.jmb.2014.10.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 10/15/2014] [Accepted: 10/26/2014] [Indexed: 11/24/2022]
Abstract
Inteins self-catalytically cleave out of precursor proteins while ligating the surrounding extein fragments with a native peptide bond. Much attention has been lavished on these molecular marvels with the hope of understanding and harnessing their chemistry for novel biochemical transformations including coupling peptides from synthetic or biological origins and controlling protein function. Despite an abundance of powerful applications, the use of inteins is still hampered by limitations in our understanding of their specificity (defined as flanking sequences that permit splicing) and the challenge of inserting inteins into target proteins. We examined the frequently used Nostoc punctiforme Npu DnaE intein after the C-extein cysteine nucleophile (Cys+1) was mutated to serine or threonine. Previous studies demonstrated reduced rates and/or splicing yields with the Npu DnaE intein after mutation of Cys+1 to Ser+1. In this study, genetic selection identified extein sequences with Ser+1 that enabled the Npu DnaE intein to splice with only a 5-fold reduction in rate compared to the wild-type Cys+1 intein and without mutation of the intein itself to activate Ser+1 as a nucleophile. Three different proteins spliced efficiently after insertion of the intein flanked by the selected sequences. We then used this selected specificity to achieve traceless splicing in a targeted enzyme at a location predicted by primary sequence similarity to only the selected C-extein sequence. This study highlights the latent catalytic potential of the Npu DnaE intein to splice with an alternative nucleophile and enables broader intein utility by increasing insertion site choices.
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Affiliation(s)
- Manoj Cheriyan
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Siu-Hong Chan
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Francine Perler
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA.
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48
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Schaerli Y, Gili M, Isalan M. A split intein T7 RNA polymerase for transcriptional AND-logic. Nucleic Acids Res 2014; 42:12322-8. [PMID: 25262348 PMCID: PMC4231753 DOI: 10.1093/nar/gku884] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Synthetic biology has developed numerous parts for building synthetic gene circuits. However, few parts have been described for prokaryotes to integrate two signals at a promoter in an AND fashion, i.e. the promoter is only activated in the presence of both signals. Here we present a new part for this function: a split intein T7 RNA polymerase. We divide T7 RNA polymerase into two expression domains and fuse each to a split intein. Only when both domains are expressed does the split intein mediate protein trans-splicing, yielding a full-length T7 RNA polymerase that can transcribe genes via a T7 promoter. We demonstrate an AND gate with the new part: the signal-to-background ratio is very high, resulting in an almost digital signal. This has utility for more complex circuits and so we construct a band-pass filter in Escherichia coli. The split intein approach should be widely applicable for engineering artificial gene circuit parts.
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Affiliation(s)
- Yolanda Schaerli
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Magüi Gili
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Mark Isalan
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), Dr. Aiguader 88, 08003 Barcelona, Spain Universitat Pompeu Fabra (UPF), Barcelona, Spain Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
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Subramanyam P, Colecraft HM. Ion channel engineering: perspectives and strategies. J Mol Biol 2014; 427:190-204. [PMID: 25205552 DOI: 10.1016/j.jmb.2014.09.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/01/2014] [Indexed: 01/19/2023]
Abstract
Ion channels facilitate the passive movement of ions down an electrochemical gradient and across lipid bilayers in cells. This phenomenon is essential for life and underlies many critical homeostatic processes in cells. Ion channels are diverse and differ with respect to how they open and close (gating) and to their ionic conductance/selectivity (permeation). Fundamental understanding of ion channel structure-function mechanisms, their physiological roles, how their dysfunction leads to disease, their utility as biosensors, and development of novel molecules to modulate their activity are important and active research frontiers. In this review, we focus on ion channel engineering approaches that have been applied to investigate these aspects of ion channel function, with a major emphasis on voltage-gated ion channels.
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Affiliation(s)
- Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University, NY, 10032, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, NY, 10032, USA.
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50
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Abstract
Inteins are autoprocessing domains that cut themselves out of host proteins in a traceless manner. This process, known as protein splicing, involves multiple chemical steps that must be coordinated to ensure fidelity in the process. The committed step in splicing involves attack of a conserved Asn side-chain amide on the adjacent backbone amide, leading to an intein-succinimide product and scission of that peptide bond. This cleavage reaction is stimulated by formation of a branched intermediate in the splicing process. The mechanism by which the Asn side-chain becomes activated as a nucleophile is not understood. Here we solve the crystal structure of an intein trapped in the branched intermediate step in protein splicing. Guided by this structure, we use protein-engineering approaches to show that intein-succinimide formation is critically dependent on a backbone-to-side-chain hydrogen-bond. We propose that this interaction serves to both position the side-chain amide for attack and to activate its nitrogen as a nucleophile. Collectively, these data provide an unprecedented view of an intein poised to carry out the rate-limiting step in protein splicing, shedding light on how a nominally nonnucleophilic group, a primary amide, can become activated in a protein active site.
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