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Biggs BW, de Paz AM, Bhan NJ, Cybulski TR, Church GM, Tyo KEJ. Engineering Ca 2+-Dependent DNA Polymerase Activity. ACS Synth Biol 2023; 12:3301-3311. [PMID: 37856140 DOI: 10.1021/acssynbio.3c00302] [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: 10/20/2023]
Abstract
Advancements in synthetic biology have provided new opportunities in biosensing, with applications ranging from genetic programming to diagnostics. Next generation biosensors aim to expand the number of accessible environments for measurements, increase the number of measurable phenomena, and improve the quality of the measurement. To this end, an emerging area in the field has been the integration of DNA as an information storage medium within biosensor outputs, leveraging nucleic acids to record the biosensor state over time. However, slow signal transduction steps, due to the time scales of transcription and translation, bottleneck many sensing-DNA recording approaches. DNA polymerases (DNAPs) have been proposed as a solution to the signal transduction problem by operating as both the sensor and responder, but there is presently a lack of DNAPs with functional sensitivity to many desirable target ligands. Here, we engineer components of the Pol δ replicative polymerase complex of Saccharomyces cerevisiae to sense and respond to Ca2+, a metal cofactor relevant to numerous biological phenomena. Through domain insertion and binding site grafting to Pol δ subunits, we demonstrate functional allosteric sensitivity to Ca2+. Together, this work provides an important foundation for future efforts in the development of DNAP-based biosensors.
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Affiliation(s)
- Bradley W Biggs
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Alexandra M de Paz
- Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Namita J Bhan
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Thaddeus R Cybulski
- Interdepartmental Neuroscience Program, Northwestern University, Chicago, Illinois 60611, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Keith E J Tyo
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
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Ren C, Wen X, Mencius J, Quan S. Selection and screening strategies in directed evolution to improve protein stability. BIORESOUR BIOPROCESS 2019. [DOI: 10.1186/s40643-019-0288-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractProtein stability is not only fundamental for experimental, industrial, and therapeutic applications, but is also the baseline for evolving novel protein functions. For decades, stability engineering armed with directed evolution has continued its rapid development and inevitably poses challenges. Generally, in directed evolution, establishing a reliable link between a genotype and any interpretable phenotype is more challenging than diversifying genetic libraries. Consequently, we set forth in a small picture to emphasize the screening or selection techniques in protein stability-directed evolution to secure the link. For a more systematic review, two main branches of these techniques, namely cellular or cell-free display and stability biosensors, are expounded with informative examples.
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Golob-Urbanc A, Rajčević U, Strmšek Ž, Jerala R. Design of split superantigen fusion proteins for cancer immunotherapy. J Biol Chem 2019; 294:6294-6305. [PMID: 30782846 DOI: 10.1074/jbc.ra118.006742] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/26/2019] [Indexed: 11/06/2022] Open
Abstract
Several antibody-targeting cancer immunotherapies have been developed based on T cell activation at the target cells. One of the most potent activators of T cells are bacterial superantigens, which bind to major histocompatibility complex class II on antigen-presenting cells and activate T cells through T cell receptor. Strong T cell activation is also one of the main weaknesses of this strategy as it may lead to systemic T cell activation. To overcome the limitation of conventional antibody-superantigen fusion proteins, we have split a superantigen into two fragments, individually inactive, until both fragments came into close proximity and reassembled into a biologically active form capable of activating T cell response. A screening method based on fusion between SEA and coiled-coil heterodimers was developed that enabled detection of functional split SEA designs. The split SEA design that demonstrated efficacy in fusion with coiled-coil dimer forming polypeptides was fused to a single chain antibody specific for tumor antigen CD20. This design selectively activated T cells by split SEA-scFv fusion binding to target cells.
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Affiliation(s)
- Anja Golob-Urbanc
- From the Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.,Graduate School of Biomedicine, University of Ljubljana, 1000 Ljubljana, Slovenia, and
| | - Uroš Rajčević
- Department of Research and Development, Blood Transfusion Centre of Slovenia, Šlajmerjeva 6, 1000 Ljubljana, Slovenia
| | - Žiga Strmšek
- From the Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.,Graduate School of Biomedicine, University of Ljubljana, 1000 Ljubljana, Slovenia, and
| | - Roman Jerala
- From the Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia,
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Segall-Shapiro TH, Meyer AJ, Ellington AD, Sontag ED, Voigt CA. A 'resource allocator' for transcription based on a highly fragmented T7 RNA polymerase. Mol Syst Biol 2014; 10:742. [PMID: 25080493 PMCID: PMC4299498 DOI: 10.15252/msb.20145299] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Synthetic genetic systems share resources with the host, including machinery for transcription
and translation. Phage RNA polymerases (RNAPs) decouple transcription from the host and generate
high expression. However, they can exhibit toxicity and lack accessory proteins (σ factors
and activators) that enable switching between different promoters and modulation of activity. Here,
we show that T7 RNAP (883 amino acids) can be divided into four fragments that have to be
co-expressed to function. The DNA-binding loop is encoded in a C-terminal 285-aa ‘σ
fragment’, and fragments with different specificity can direct the remaining 601-aa
‘core fragment’ to different promoters. Using these parts, we have built a resource
allocator that sets the core fragment concentration, which is then shared by multiple σ
fragments. Adjusting the concentration of the core fragment sets the maximum transcriptional
capacity available to a synthetic system. Further, positive and negative regulation is implemented
using a 67-aa N-terminal ‘α fragment’ and a null (inactivated) σ
fragment, respectively. The α fragment can be fused to recombinant proteins to make promoters
responsive to their levels. These parts provide a toolbox to allocate transcriptional resources via
different schemes, which we demonstrate by building a system which adjusts promoter activity to
compensate for the difference in copy number of two plasmids.
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Affiliation(s)
- Thomas H Segall-Shapiro
- Department of Biological Engineering, Synthetic Biology Center Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Adam J Meyer
- Institute for Cellular and Molecular Biology University of Texas at Austin, Austin, TX, USA
| | - Andrew D Ellington
- Institute for Cellular and Molecular Biology University of Texas at Austin, Austin, TX, USA
| | - Eduardo D Sontag
- Department of Mathematics, Rutgers University, Piscataway, NJ, USA
| | - Christopher A Voigt
- Department of Biological Engineering, Synthetic Biology Center Massachusetts Institute of Technology, Cambridge, MA, USA
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5
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Improvement of stability of nitrile hydratase via protein fragment swapping. Biochem Biophys Res Commun 2014; 450:401-8. [DOI: 10.1016/j.bbrc.2014.05.127] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 05/27/2014] [Indexed: 11/21/2022]
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Tuning the substrate selectivity of meta-cleavage product hydrolase by domain swapping. Appl Microbiol Biotechnol 2012; 97:5343-50. [DOI: 10.1007/s00253-012-4405-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 08/29/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
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Goldsmith M, Tawfik DS. Directed enzyme evolution: beyond the low-hanging fruit. Curr Opin Struct Biol 2012; 22:406-12. [DOI: 10.1016/j.sbi.2012.03.010] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 03/14/2012] [Accepted: 03/14/2012] [Indexed: 12/26/2022]
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Slaska-Kiss K, Tímár E, Kiss A. Complementation between inactive fragments of SssI DNA methyltransferase. BMC Mol Biol 2012; 13:17. [PMID: 22646482 PMCID: PMC3404938 DOI: 10.1186/1471-2199-13-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/30/2012] [Indexed: 02/01/2023] Open
Abstract
Background Silencing mammalian genes by targeted DNA (cytosine-5) methylation of selected CG sites in the genome would be a powerful technique to analyze epigenomic information and to study the roles of DNA methylation in physiological and pathological states. A promising approach of targeted DNA methylation is based on the ability of split fragments of a monomeric DNA methyltransferase (C5-MTase) to associate and form active enzyme. A few C5-MTases of different specificities have been shown to possess the ability of fragment complementation, but a demonstration of this phenomenon for a C5-MTase, which has CG specificity and thus can be targeted to methylate any CG site, has been lacking. The purpose of this study was to test whether the CG-specific prokaryotic C5-MTase M.SssI shows the phenomenon of fragment complementation. Results We show that truncated inactive N-terminal fragments of M.SssI can assemble with truncated inactive C-terminal fragments to form active enzyme in vivo when produced in the same E. coli cell. Overlapping and non-overlapping fragments as well as fragments containing short appended foreign sequences had complementation capacity. In optimal combinations C-terminal fragments started between conserved motif VIII and the predicted target recognizing domain of M.SssI. DNA methyltransferase activity in crude extracts of cells with the best complementing fragment pairs was ~ 4 per cent of the activity of cells producing the full length enzyme. Fusions of two N-terminal and two C-terminal fragments to 21.6 kDa zinc finger domains only slightly reduced complementation ability of the fragments. Conclusions The CG-specific DNA methyltransferase M.SssI shows the phenomenon of fragment complementation in vivo in E. coli. Fusion of the split fragments to six unit zinc finger domains does not substantially interfere with the formation of active enzyme. These observations and the large number of complementing fragment combinations representing a wide range of MTase activity offer the possibility to develop M.SssI into a programmable DNA methyltransferase of high specificity.
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Affiliation(s)
- Krystyna Slaska-Kiss
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary
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Pétrin D, Hébert TE. Imaging-based approaches to understanding g protein-coupled receptor signalling complexes. Methods Mol Biol 2011; 756:37-60. [PMID: 21870219 DOI: 10.1007/978-1-61779-160-4_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In the last 10 years, imaging assays based on resonance energy transfer (RET) and protein fragment complementation have made it possible to study interactions between components of G protein-coupled receptor (GPCR) signalling complexes in living cells under physiological conditions. Here, we consider the history of such approaches, the current tools available and how they have changed our understanding of GPCR signalling. We also discuss some theoretical and methodological issues important when combining the different types of assay.
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Affiliation(s)
- Darlaine Pétrin
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
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Segall-Shapiro TH, Nguyen PQ, Dos Santos ED, Subedi S, Judd J, Suh J, Silberg JJ. Mesophilic and hyperthermophilic adenylate kinases differ in their tolerance to random fragmentation. J Mol Biol 2010; 406:135-48. [PMID: 21145325 DOI: 10.1016/j.jmb.2010.11.057] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 11/15/2010] [Accepted: 11/30/2010] [Indexed: 02/03/2023]
Abstract
The extent to which thermostability influences the location of protein fragmentation sites that allow retention of function is not known. To evaluate this, we used a novel transposase-based approach to create libraries of vectors that express structurally-related fragments of Bacillus subtilis adenylate kinase (BsAK) and Thermotoga neapolitana adenylate kinase (TnAK) with identical modifications at their termini, and we selected for variants in each library that complement the growth of Escherichia coli with a temperature-sensitive adenylate kinase (AK). Mutants created using the hyperthermophilic TnAK were found to support growth with a higher frequency (44%) than those generated from the mesophilic BsAK (6%), and selected TnAK mutants complemented E. coli growth more strongly than homologous BsAK variants. Sequencing of functional clones from each library also identified a greater dispersion of fragmentation sites within TnAK. Nondisruptive fission sites were observed within the AMP binding and core domains of both AK homologs. However, only TnAK contained sites within the lid domain, which undergoes dynamic fluctuations that are critical for catalysis. These findings implicate the flexible lid domain as having an increased sensitivity to fission events at physiological temperatures. In addition, they provide evidence that comparisons of nondisruptive fission sites in homologous proteins could be useful for finding dynamic regions whose conformational fluctuations are important for function, and they show that the discovery of protein fragments that cooperatively function in mesophiles can be aided by the use of thermophilic enzymes as starting points for protein design.
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Affiliation(s)
- Thomas H Segall-Shapiro
- Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street, MS 140, Houston, TX 77005, USA
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Ketteler R. The Feynman trajectories: determining the path of a protein using fixed-endpoint assays. ACTA ACUST UNITED AC 2010; 15:321-6. [PMID: 20130209 DOI: 10.1177/1087057109357116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Richard Feynman postulated in 1948 that the path of an electron can be best described by the sum or functional integral of all possible trajectories rather than by the notion of a single, unique trajectory. As a consequence, the position of an electron does not harbor any information about the paths that contributed to this position. This observation constitutes a classical endpoint observation. The endpoint assay is the desired type of experiment for high-throughput screening applications, mainly because of limitations in data acquisition and handling. Quite contrary to electrons, it is possible to extract information about the path of a protein using endpoint assays, and these types of applications are reviewed in this article.
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Affiliation(s)
- Robin Ketteler
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom.
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