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Krebs SK, Rakotoarinoro N, Stech M, Zemella A, Kubick S. A CHO-Based Cell-Free Dual Fluorescence Reporter System for the Straightforward Assessment of Amber Suppression and scFv Functionality. Front Bioeng Biotechnol 2022; 10:873906. [PMID: 35573244 PMCID: PMC9098822 DOI: 10.3389/fbioe.2022.873906] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/25/2022] [Indexed: 11/29/2022] Open
Abstract
Incorporation of noncanonical amino acids (ncAAs) with bioorthogonal reactive groups by amber suppression allows the generation of synthetic proteins with desired novel properties. Such modified molecules are in high demand for basic research and therapeutic applications such as cancer treatment and in vivo imaging. The positioning of the ncAA-responsive codon within the protein’s coding sequence is critical in order to maintain protein function, achieve high yields of ncAA-containing protein, and allow effective conjugation. Cell-free ncAA incorporation is of particular interest due to the open nature of cell-free systems and their concurrent ease of manipulation. In this study, we report a straightforward workflow to inquire ncAA positions in regard to incorporation efficiency and protein functionality in a Chinese hamster ovary (CHO) cell-free system. As a model, the well-established orthogonal translation components Escherichia coli tyrosyl-tRNA synthetase (TyrRS) and tRNATyrCUA were used to site-specifically incorporate the ncAA p-azido-l-phenylalanine (AzF) in response to UAG codons. A total of seven ncAA sites within an anti-epidermal growth factor receptor (EGFR) single-chain variable fragment (scFv) N-terminally fused to the red fluorescent protein mRFP1 and C-terminally fused to the green fluorescent protein sfGFP were investigated for ncAA incorporation efficiency and impact on antigen binding. The characterized cell-free dual fluorescence reporter system allows screening for ncAA incorporation sites with high incorporation efficiency that maintain protein activity. It is parallelizable, scalable, and easy to operate. We propose that the established CHO-based cell-free dual fluorescence reporter system can be of particular interest for the development of antibody-drug conjugates (ADCs).
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Affiliation(s)
- Simon K. Krebs
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
- Institute for Biotechnology, Technical University of Berlin, Berlin, Germany
| | - Nathanaël Rakotoarinoro
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
- Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Marlitt Stech
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
| | - Anne Zemella
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
- Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus - Senftenberg, the Brandenburg Medical School Theodor Fontane and the University of Potsdam, Potsdam, Germany
- *Correspondence: Stefan Kubick,
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2
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Assessing Site-specific PEGylation of TEM-1 β-lactamase with Cell-free Protein Synthesis and Coarse-grained Simulation. J Biotechnol 2022; 345:55-63. [PMID: 34995558 DOI: 10.1016/j.jbiotec.2021.12.016] [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: 09/17/2021] [Revised: 12/27/2021] [Accepted: 12/30/2021] [Indexed: 11/21/2022]
Abstract
PEGylation is a broadly used strategy to enhance the pharmacokinetic properties of therapeutic proteins. It is well established that the location and extent of PEGylation have a significant impact on protein properties. However, conventional PEGylation techniques have limited control over PEGylation sites. Emerging site-specific PEGylation technology provides control of PEG placement by conjugating PEG polymers via click chemistry reaction to genetically encoded non-canonical amino acids. Unfortunately, a method to rapidly determine the optimal PEGylation location has yet to be established. Here we seek to address this challenge. In this work, coarse-grained molecular dynamic simulations are paired with high-throughput experimental screening utilizing cell-free protein synthesis to investigate the effect of site-specific PEGylation on the two-state folder protein TEM-1 β-lactamase. Specifically, the conjugation efficiency, thermal stability, and enzymatic activity are studied for the enzyme PEGylated at several different locations. The results of this analysis confirm that the physical properties of the PEGylated protein vary considerably with PEGylation site and that traditional design recommendations are insufficient to predict favorable PEGylation sites. In this study, the best predictor of the most favorable conjugation site is coarse-grained simulation. Thus, we propose a dual combinatorial screening approach in which coarse-grained molecular simulation informs site selection for high-throughput experimental verification.
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3
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Giannakoulias S, Shringari SR, Ferrie JJ, Petersson EJ. Biomolecular simulation based machine learning models accurately predict sites of tolerability to the unnatural amino acid acridonylalanine. Sci Rep 2021; 11:18406. [PMID: 34526629 PMCID: PMC8443755 DOI: 10.1038/s41598-021-97965-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/17/2021] [Indexed: 11/08/2022] Open
Abstract
The incorporation of unnatural amino acids (Uaas) has provided an avenue for novel chemistries to be explored in biological systems. However, the successful application of Uaas is often hampered by site-specific impacts on protein yield and solubility. Although previous efforts to identify features which accurately capture these site-specific effects have been unsuccessful, we have developed a set of novel Rosetta Custom Score Functions and alternative Empirical Score Functions that accurately predict the effects of acridon-2-yl-alanine (Acd) incorporation on protein yield and solubility. Acd-containing mutants were simulated in PyRosetta, and machine learning (ML) was performed using either the decomposed values of the Rosetta energy function, or changes in residue contacts and bioinformatics. Using these feature sets, which represent Rosetta score function specific and bioinformatics-derived terms, ML models were trained to predict highly abstract experimental parameters such as mutant protein yield and solubility and displayed robust performance on well-balanced holdouts. Model feature importance analyses demonstrated that terms corresponding to hydrophobic interactions, desolvation, and amino acid angle preferences played a pivotal role in predicting tolerance of mutation to Acd. Overall, this work provides evidence that the application of ML to features extracted from simulated structural models allow for the accurate prediction of diverse and abstract biological phenomena, beyond the predictivity of traditional modeling and simulation approaches.
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Affiliation(s)
- Sam Giannakoulias
- Department of Chemistry, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA, 19104, USA
| | - Sumant R Shringari
- Department of Chemistry, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA, 19104, USA
| | - John J Ferrie
- Department of Molecular & Cell Biology, University of California, Berkeley, 475B Li Ka Shing Center, Berkeley, CA, 94720, USA.
| | - E James Petersson
- Department of Chemistry, University of Pennsylvania, 231 S. 34th St, Philadelphia, PA, 19104, USA.
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4
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Johnson RL, Blaber HG, Evans T, Worthy HL, Pope JR, Jones DD. Designed Artificial Protein Heterodimers With Coupled Functions Constructed Using Bio-Orthogonal Chemistry. Front Chem 2021; 9:733550. [PMID: 34422774 PMCID: PMC8371201 DOI: 10.3389/fchem.2021.733550] [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: 06/30/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
The formation of protein complexes is central to biology, with oligomeric proteins more prevalent than monomers. The coupling of functionally and even structurally distinct protein units can lead to new functional properties not accessible by monomeric proteins alone. While such complexes are driven by evolutionally needs in biology, the ability to link normally functionally and structurally disparate proteins can lead to new emergent properties for use in synthetic biology and the nanosciences. Here we demonstrate how two disparate proteins, the haem binding helical bundle protein cytochrome b 562 and the β-barrel green fluorescent protein can be combined to form a heterodimer linked together by an unnatural triazole linkage. The complex was designed using computational docking approaches to predict compatible interfaces between the two proteins. Models of the complexes where then used to engineer residue coupling sites in each protein to link them together. Genetic code expansion was used to incorporate azide chemistry in cytochrome b 562 and alkyne chemistry in GFP so that a permanent triazole covalent linkage can be made between the two proteins. Two linkage sites with respect to GFP were sampled. Spectral analysis of the new heterodimer revealed that haem binding and fluorescent protein chromophore properties were retained. Functional coupling was confirmed through changes in GFP absorbance and fluorescence, with linkage site determining the extent of communication between the two proteins. We have thus shown here that is possible to design and build heterodimeric proteins that couple structurally and functionally disparate proteins to form a new complex with new functional properties.
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Affiliation(s)
- Rachel L. Johnson
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Hayley G. Blaber
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
- The Henry Wellcome Building for Biocatalysis, Exeter University, Exeter, United Kingdom
| | - Tomas Evans
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Harley L. Worthy
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
- The Henry Wellcome Building for Biocatalysis, Exeter University, Exeter, United Kingdom
| | - Jacob R. Pope
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - D. Dafydd Jones
- Molecular Biosciences Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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5
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Pagar AD, Patil MD, Flood DT, Yoo TH, Dawson PE, Yun H. Recent Advances in Biocatalysis with Chemical Modification and Expanded Amino Acid Alphabet. Chem Rev 2021; 121:6173-6245. [PMID: 33886302 DOI: 10.1021/acs.chemrev.0c01201] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The two main strategies for enzyme engineering, directed evolution and rational design, have found widespread applications in improving the intrinsic activities of proteins. Although numerous advances have been achieved using these ground-breaking methods, the limited chemical diversity of the biopolymers, restricted to the 20 canonical amino acids, hampers creation of novel enzymes that Nature has never made thus far. To address this, much research has been devoted to expanding the protein sequence space via chemical modifications and/or incorporation of noncanonical amino acids (ncAAs). This review provides a balanced discussion and critical evaluation of the applications, recent advances, and technical breakthroughs in biocatalysis for three approaches: (i) chemical modification of cAAs, (ii) incorporation of ncAAs, and (iii) chemical modification of incorporated ncAAs. Furthermore, the applications of these approaches and the result on the functional properties and mechanistic study of the enzymes are extensively reviewed. We also discuss the design of artificial enzymes and directed evolution strategies for enzymes with ncAAs incorporated. Finally, we discuss the current challenges and future perspectives for biocatalysis using the expanded amino acid alphabet.
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Affiliation(s)
- Amol D Pagar
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea
| | - Mahesh D Patil
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea
| | - Dillon T Flood
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Tae Hyeon Yoo
- Department of Molecular Science and Technology, Ajou University, 206 World cup-ro, Yeongtong-gu, Suwon 16499, Korea
| | - Philip E Dawson
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Hyungdon Yun
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Korea
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6
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Auhim HS, Grigorenko BL, Harris TK, Aksakal OE, Polyakov IV, Berry C, Gomes GDP, Alabugin IV, Rizkallah PJ, Nemukhin AV, Jones DD. Stalling chromophore synthesis of the fluorescent protein Venus reveals the molecular basis of the final oxidation step. Chem Sci 2021; 12:7735-7745. [PMID: 34168826 PMCID: PMC8188506 DOI: 10.1039/d0sc06693a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/26/2021] [Indexed: 11/24/2022] Open
Abstract
Fluorescent proteins (FPs) have revolutionised the life sciences, but the mechanism of chromophore maturation is still not fully understood. Here we show that incorporation of a photo-responsive non-canonical amino acid within the chromophore stalls maturation of Venus, a yellow FP, at an intermediate stage; a crystal structure indicates the presence of O2 located above a dehydrated enolate form of the imidazolone ring, close to the strictly conserved Gly67 that occupies a twisted conformation. His148 adopts an "open" conformation so forming a channel that allows O2 access to the immature chromophore. Absorbance spectroscopy supported by QM/MM simulations suggests that the first oxidation step involves formation of a hydroperoxyl intermediate in conjunction with dehydrogenation of the methylene bridge. A fully conjugated mature chromophore is formed through release of H2O2, both in vitro and in vivo. The possibility of interrupting and photochemically restarting chromophore maturation and the mechanistic insights open up new approaches for engineering optically controlled fluorescent proteins.
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Affiliation(s)
- Husam Sabah Auhim
- School of Biosciences, Molecular Biosciences Division, Cardiff University Sir Martin Evans Building Cardiff CF10 3AX UK +44 (0)29 2087 4290
- Department of Biology, College of Science, University of Baghdad Baghdad Iraq
| | - Bella L Grigorenko
- Chemistry Department, Lomonosov Moscow State University Leninskie Gory, 1-3 Moscow Russian Federation +7 495 939 1096
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences Moscow Russian Federation
| | - Tessa K Harris
- School of Biosciences, Molecular Biosciences Division, Cardiff University Sir Martin Evans Building Cardiff CF10 3AX UK +44 (0)29 2087 4290
| | - Ozan E Aksakal
- School of Biosciences, Molecular Biosciences Division, Cardiff University Sir Martin Evans Building Cardiff CF10 3AX UK +44 (0)29 2087 4290
| | - Igor V Polyakov
- Chemistry Department, Lomonosov Moscow State University Leninskie Gory, 1-3 Moscow Russian Federation +7 495 939 1096
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences Moscow Russian Federation
| | - Colin Berry
- School of Biosciences, Molecular Biosciences Division, Cardiff University Sir Martin Evans Building Cardiff CF10 3AX UK +44 (0)29 2087 4290
| | - Gabriel Dos Passos Gomes
- Department of Chemistry, University of Toronto 80 St. George Street Toronto ON M5S 3H6 Canada
- Department of Computer Science, University of Toronto 214 College St. Toronto Ontario M5T 3A1 Canada
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University Tallahassee Fl 32306 USA +1 850 644 5795
| | | | - Alexander V Nemukhin
- Chemistry Department, Lomonosov Moscow State University Leninskie Gory, 1-3 Moscow Russian Federation +7 495 939 1096
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences Moscow Russian Federation
| | - D Dafydd Jones
- School of Biosciences, Molecular Biosciences Division, Cardiff University Sir Martin Evans Building Cardiff CF10 3AX UK +44 (0)29 2087 4290
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7
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Hostetler ZM, Ferrie JJ, Bornstein MR, Sungwienwong I, Petersson EJ, Kohli RM. Systematic Evaluation of Soluble Protein Expression Using a Fluorescent Unnatural Amino Acid Reveals No Reliable Predictors of Tolerability. ACS Chem Biol 2018; 13:2855-2861. [PMID: 30216041 PMCID: PMC6195468 DOI: 10.1021/acschembio.8b00696] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Improvements in genetic code expansion have made preparing proteins with diverse functional groups almost routine. Nonetheless, unnatural amino acids (Uaas) pose theoretical burdens on protein solubility, and determinants of position-specific tolerability to Uaas remain underexplored. To broadly examine associations, we systematically assessed the effect of substituting the fluorescent Uaa, acridonylalanine, at more than 50 chemically, evolutionarily, and structurally diverse residues in two bacterial proteins: LexA and RecA. Surprisingly, properties that ostensibly contribute to Uaa tolerability-such as conservation, hydrophobicity, or accessibility-demonstrated no consistent correlations with resulting protein solubility. Instead, solubility is closely dependent on the location of the substitution within the overall tertiary structure, suggesting that intrinsic properties of protein domains, and not individual positions, are stronger determinants of Uaa tolerability. Consequently, those who seek to install Uaas in new target proteins should consider broadening, rather than narrowing, the types of residues screened for Uaa incorporation.
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Affiliation(s)
- Zachary M. Hostetler
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - John J. Ferrie
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Marc R. Bornstein
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Itthipol Sungwienwong
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Rahul M. Kohli
- Department of Medicine, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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8
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Wilding KM, Smith AK, Wilkerson JW, Bush DB, Knotts TA, Bundy BC. The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation. ACS Synth Biol 2018; 7:510-521. [PMID: 29295615 DOI: 10.1021/acssynbio.7b00316] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here.
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Affiliation(s)
- Kristen M. Wilding
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, United States
| | - Addison K. Smith
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, United States
| | - Joshua W. Wilkerson
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, United States
| | - Derek B. Bush
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, United States
| | - Thomas A. Knotts
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, United States
| | - Bradley C. Bundy
- Department of Chemical Engineering, Brigham Young University, Provo, Utah 84602, United States
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9
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Zaki AJ, Hartley A, Reddington SC, Thomas SK, Watson P, Hayes A, Moskalenko AV, Craciun MF, Macdonald JE, Jones DD, Elliott M. Defined covalent assembly of protein molecules on graphene using a genetically encoded photochemical reaction handle. RSC Adv 2018; 8:5768-5775. [PMID: 35539607 PMCID: PMC9078156 DOI: 10.1039/c7ra11166e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/11/2018] [Indexed: 11/27/2022] Open
Abstract
We have created modified protein variants by introducing a non-canonical amino acid p-azido-l-phenylalanine (azF) into defined positions for photochemically-induced covalent attachment to graphene. Attachment of GFP, TEM and cyt b562 proteins was verified through a combination of atomic force and scanning tunnelling microscopy, resistance measurements, Raman data and fluorescence measurements. This method can in principle be extended to any protein which can be engineered in this way without adversely affecting its structural stability. We demonstrate a general method for photochemically-induced covalent attachment of proteins to graphene through the introduction of a non-canonical amino acid p-azido-l-phenylalanine into defined residue positions.![]()
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Affiliation(s)
- Athraa J. Zaki
- School of Physics and Astronomy
- Cardiff University
- Cardiff CF24 3AA
- UK
| | | | | | | | | | | | | | | | | | | | - Martin Elliott
- School of Physics and Astronomy
- Cardiff University
- Cardiff CF24 3AA
- UK
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10
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Approaches to single-molecule studies of metalloprotein electron transfer using scanning probe-based techniques. Biochem Soc Trans 2017; 46:1-9. [DOI: 10.1042/bst20170229] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/17/2017] [Accepted: 11/21/2017] [Indexed: 01/30/2023]
Abstract
The single-molecule properties of metalloproteins have provided an intensely active research area in recent years. This brief review covers some of the techniques used to prepare, measure and analyse the electron transfer properties of metalloproteins, concentrating on scanning tunnelling microscopy-based techniques and advances in attachment of proteins to electrodes.
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11
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Chen Y, Lu L, Ye S. Genetic Code Expansion and Optoproteomics. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2017; 90:599-610. [PMID: 29259524 PMCID: PMC5733852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Nature has invented photoreceptor proteins that are involved in sensing and response to light in living organisms. Genetic code expansion (GCE) technology has provided new tools to transform light insensitive proteins into novel photoreceptor proteins. It is achieved by the site-specific incorporation of unnatural amino acids (Uaas) that carry light sensitive moieties serving as "pigments" that react to light via photo-decaging, cross-linking, or isomerization. Over the last two decades, various proteins including ion channels, GPCRs, transporters, and kinases have been successfully rendered light responsive owing to the functionalities of Uaas. Very recently, Cas9 protein has been engineered to enable light activation of genomic editing by CRISPR. Those novel proteins have not only led to discoveries of dynamic protein conformational changes with implications in diseases, but also facilitated the screening of ligand-protein and protein-protein interactions of pharmacological significance. This review covers the genetic editing principles for genetic code expansion and design concepts that guide the engineering of light-sensitive proteins. The applications have brought up a new concept of "optoproteomics" that, in contrast to "optogenetics," aims to combine optical methods and site-specific proteomics for investigating and intervening in biological functions.
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Affiliation(s)
- Yuting Chen
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University (ECNU), Shanghai, China
| | - Linjie Lu
- Université Pierre-et-Marie-Curie, Laboratory of Computational and Quantitative Biology (LCQB), Institute of Biology Paris-Seine, Paris, France
| | - Shixin Ye
- Université Pierre-et-Marie-Curie, Laboratory of Computational and Quantitative Biology (LCQB), Institute of Biology Paris-Seine, Paris, France,Institut National de la Santé et de la Recherche Médicale, Paris, France,Centre National de la Recherche Scientifique, Paris, France,To whom all correspondence should be addressed: Shixin Ye-Lehmann, Laboratory of Computational and Quantitative Biology, Institute of Biology Paris-Seine, University of Pierre and Marie Curie, Bldg. C, 3rd floor, Room 311a, 4 Place Jussieu, 75006 Paris, France, Tel: 33.(0)1.44.27.60.57, .
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12
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Liu SS, Wei X, Ji Q, Xin X, Jiang B, Liu J. A facile and efficient transposon mutagenesis method for generation of multi-codon deletions in protein sequences. J Biotechnol 2016; 227:27-34. [DOI: 10.1016/j.jbiotec.2016.03.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 03/17/2016] [Accepted: 03/21/2016] [Indexed: 12/17/2022]
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13
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Liu SS, Wei X, Dong X, Xu L, Liu J, Jiang B. Structural plasticity of green fluorescent protein to amino acid deletions and fluorescence rescue by folding-enhancing mutations. BMC BIOCHEMISTRY 2015. [PMID: 26206151 PMCID: PMC4513630 DOI: 10.1186/s12858-015-0046-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Green fluorescent protein (GFP) and its derivative fluorescent proteins (FPs) are among the most commonly used reporter systems for studying gene expression and protein interaction in biomedical research. Most commercially available FPs have been optimized for their oligomerization state to prevent potential structural constraints that may interfere with the native function of fused proteins. Other approach to reducing structural constraints may include minimizing the structure of GFPs. Previous studies in an enhanced GFP variant (EGFP) identified a series of deletions that can retain GFP fluorescence. In this study, we interrogated the structural plasticity of a UV-optimized GFP variant (GFP(UV)) to amino acid deletions, characterized the effects of deletions and explored the feasibility of rescuing the fluorescence of deletion mutants using folding-enhancing mutations. METHODS Transposon mutagenesis was used to screen amino acid deletions in GFP that led to fluorescent and nonfluorescent phenotypes. The fluorescent GFP mutants were characterized for their whole-cell fluorescence and fraction soluble. Fluorescent GFP mutants with internal deletions were purified and characterized for their spectral and folding properties. Folding-ehancing mutations were introduced to deletion mutants to rescue their compromised fluorescence. RESULTS We identified twelve amino acid deletions that can retain the fluorescence of GFP(UV). Seven of these deletions are either at the N- or C- terminus, while the other five are located at internal helices or strands. Further analysis suggested that the five internal deletions diminished the efficiency of protein folding and chromophore maturation. Protein expression under hypothermic condition or incorporation of folding-enhancing mutations could rescue the compromised fluorescence of deletion mutants. In addition, we generated dual deletion mutants that can retain GFP fluorescence. CONCLUSION Our results suggested that a "size-minimized" GFP may be developed by iterative incorporation of amino acid deletions, followed by fluorescence rescue with folding-enhancing mutations.
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Affiliation(s)
- Shu-su Liu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China.
| | - Xuan Wei
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China.
| | - Xue Dong
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China.
| | - Liang Xu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China.
| | - Jia Liu
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China. .,Department of Chemistry and Biochemistry, University of Maryland, College Park, USA.
| | - Biao Jiang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China.
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