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Nordahl L, Akkuratov EE, Heimgärtner J, Schach K, Meineke B, Elsässer S, Wennmalm S, Brismar H. Detection and quantification of Na,K-ATPase dimers in the plasma membrane of living cells by FRET-FCS. Biochim Biophys Acta Gen Subj 2024; 1868:130619. [PMID: 38643888 DOI: 10.1016/j.bbagen.2024.130619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/25/2024] [Accepted: 04/12/2024] [Indexed: 04/23/2024]
Abstract
The sodium potassium pump, Na,K-ATPase (NKA), is an integral plasma membrane protein, expressed in all eukaryotic cells. It is responsible for maintaining the transmembrane Na+ gradient and is the major determinant of the membrane potential. Self-interaction and oligomerization of NKA in cell membranes has been proposed and discussed but is still an open question. Here, we have used a combination of FRET and Fluorescence Correlation Spectroscopy, FRET-FCS, to analyze NKA in the plasma membrane of living cells. Click chemistry was used to conjugate the fluorescent labels Alexa 488 and Alexa 647 to non-canonical amino acids introduced in the NKA α1 and β1 subunits. We demonstrate that FRET-FCS can detect an order of magnitude lower concentration of green-red labeled protein pairs in a single-labeled red and green background than what is possible with cross-correlation (FCCS). We show that a significant fraction of NKA is expressed as a dimer in the plasma membrane. We also introduce a method to estimate not only the number of single and double labeled NKA, but the number of unlabeled, endogenous NKA and estimate the density of endogenous NKA at the plasma membrane to 1400 ± 800 enzymes/μm2.
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Affiliation(s)
- Linnea Nordahl
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Box 1031, 171 21 Solna, Sweden
| | - Evgeny E Akkuratov
- University of Oxford, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, Oxford OX3 9DS, UK
| | - Johannes Heimgärtner
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Box 1031, 171 21 Solna, Sweden
| | - Katja Schach
- Graduate Training Centre of Neuroscience, University of Tübingen, Otfried-Müller-Str. 27, 72076 Tübingen, Germany
| | - Birthe Meineke
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Box 1031, 171 21 Solna, Sweden
| | - Simon Elsässer
- Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Box 1031, 171 21 Solna, Sweden
| | - Stefan Wennmalm
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Box 1031, 171 21 Solna, Sweden.
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, Box 1031, 171 21 Solna, Sweden; Science for Life Laboratory, Department of Women's and Children's Health, Karolinska Institutet, Box 1031, 171 21 Solna, Sweden
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2
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Kaushik V, Chadda R, Kuppa S, Pokhrel N, Vayyeti A, Grady S, Arnatt C, Antony E. Fluorescent human RPA to track assembly dynamics on DNA. Methods 2024; 223:95-105. [PMID: 38301751 PMCID: PMC10923064 DOI: 10.1016/j.ymeth.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/25/2024] [Accepted: 01/29/2024] [Indexed: 02/03/2024] Open
Abstract
DNA metabolic processes including replication, repair, recombination, and telomere maintenance occur on single-stranded DNA (ssDNA). In each of these complex processes, dozens of proteins function together on the ssDNA template. However, when double-stranded DNA is unwound, the transiently open ssDNA is protected and coated by the high affinity heterotrimeric ssDNA binding Replication Protein A (RPA). Almost all downstream DNA processes must first remodel/remove RPA or function alongside to access the ssDNA occluded under RPA. Formation of RPA-ssDNA complexes trigger the DNA damage checkpoint response and is a key step in activating most DNA repair and recombination pathways. Thus, in addition to protecting the exposed ssDNA, RPA functions as a gatekeeper to define functional specificity in DNA maintenance and genomic integrity. RPA achieves functional dexterity through a multi-domain architecture utilizing several DNA binding and protein-interaction domains connected by flexible linkers. This flexible and modular architecture enables RPA to adopt a myriad of configurations tailored for specific DNA metabolic roles. To experimentally capture the dynamics of the domains of RPA upon binding to ssDNA and interacting proteins we here describe the generation of active site-specific fluorescent versions of human RPA (RPA) using 4-azido-L-phenylalanine (4AZP) incorporation and click chemistry. This approach can also be applied to site-specific modifications of other multi-domain proteins. Fluorescence-enhancement through non-canonical amino acids (FEncAA) and Förster Resonance Energy Transfer (FRET) assays for measuring dynamics of RPA on DNA are also described. The fluorescent human RPA described here will enable high-resolution structure-function analysis of RPA-ssDNA interactions.
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Affiliation(s)
- Vikas Kaushik
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Rahul Chadda
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Sahiti Kuppa
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Nilisha Pokhrel
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Abhinav Vayyeti
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA
| | - Scott Grady
- Department of Chemistry, St. Louis University, St. Louis, MO 63103, USA
| | - Chris Arnatt
- Department of Chemistry, St. Louis University, St. Louis, MO 63103, USA
| | - Edwin Antony
- Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, MO 63104, USA.
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3
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Natter Perdiguero A, Deliz Liang A. Practical Approaches to Genetic Code Expansion with Aminoacyl-tRNA Synthetase/tRNA Pairs. Chimia (Aarau) 2024; 78:22-31. [PMID: 38430060 DOI: 10.2533/chimia.2024.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 03/03/2024] Open
Abstract
Genetic code expansion (GCE) can enable the site-selective incorporation of non-canonical amino acids (ncAAs) into proteins. GCE has advanced tremendously in the last decade and can be used to create biorthogonal handles, monitor and control proteins inside cells, study post-translational modifications, and engineer new protein functions. Since establishing our laboratory, our research has focused on applications of GCE in protein and enzyme engineering using aminoacyl-tRNA synthetase/tRNA (aaRS/tRNA) pairs. This topic has been reviewed extensively, leaving little doubt that GCE is a powerful tool for engineering proteins and enzymes. Therefore, for this young faculty issue, we wanted to provide a more technical look into the methods we use and the challenges we think about in our laboratory. Since starting the laboratory, we have successfully engineered over a dozen novel aaRS/tRNA pairs tailored for various GCE applications. However, we acknowledge that the field can pose challenges even for experts. Thus, herein, we provide a review of methodologies in ncAA incorporation with some practical commentary and a focus on challenges, emerging solutions, and exciting developments.
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Hanaee-Ahvaz H, Cserjan-Puschmann M, Mayer F, Tauer C, Albrecht B, Furtmüller PG, Wiltschi B, Hahn R, Striedner G. Antibody fragments functionalized with non-canonical amino acids preserving structure and functionality - A door opener for new biological and therapeutic applications. Heliyon 2023; 9:e22463. [PMID: 38046162 PMCID: PMC10686840 DOI: 10.1016/j.heliyon.2023.e22463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 12/05/2023] Open
Abstract
Functionalization of proteins by incorporating reactive non-canonical amino acids (ncAAs) has been widely applied for numerous biological and therapeutic applications. The requirement not to lose the intrinsic properties of these proteins is often underestimated and not considered. Main purpose of this study was to answer the question whether functionalization via residue-specific incorporation of the ncAA N6-[(2-Azidoethoxy) carbonyl]-l-lysine (Azk) influences the properties of the anti-tumor-necrosis-factor-α-Fab (FTN2). Therefore, FTN2Azk variants with different Azk incorporation sites were designed and amber codon suppression was used for production. The functionalized FTN2Azk variants were efficiently produced in fed-batch like μ-bioreactor cultivations in the periplasm of E. coli displaying correct structure and antigen binding affinities comparable to those of wild-type FTN2. Our FTN2Azk variants with reactive handles for diverse conjugates enable tracking of recombinant protein in the production cell, pharmacological studies and translation into new pharmaceutical applications.
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Affiliation(s)
- Hana Hanaee-Ahvaz
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
| | - Florian Mayer
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
| | - Christopher Tauer
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
| | - Bernd Albrecht
- Biopharma Austria, Process Science, Boehringer Ingelheim Regional Center Vienna GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, A-1121, Vienna, Austria
| | - Paul G. Furtmüller
- University of Natural Resources and Life Sciences, Vienna, Department of Chemistry, Institute of Biochemistry, Muthgasse 18, 1190, Vienna, Austria
| | - Birgit Wiltschi
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
| | - Rainer Hahn
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, University of Natural Resources and Life Sciences, Vienna, Department of Biotechnology, Institute of Bioprocess Science and Engineering, Muthgasse 18, 1190, Vienna, Austria
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Chen W, Gunther TR, Baughman HER, Komives EA. Site-specific incorporation of biophysical probes into NF-ĸB with non-canonical amino acids. Methods 2023; 213:18-25. [PMID: 36940840 PMCID: PMC10688598 DOI: 10.1016/j.ymeth.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/14/2023] [Accepted: 03/16/2023] [Indexed: 03/23/2023] Open
Abstract
The transcription factor NF-ĸB is a central mediator of immune and inflammatory responses. To understand the regulation of NF-ĸB, it is important to probe the underlying thermodynamics, kinetics, and conformational dynamics of the NF-ĸB/IĸBα/DNA interaction network. The development of genetic incorporation of non-canonical amino acids (ncAA) has enabled the installation of biophysical probes into proteins with site specificity. Recent single-molecule FRET (smFRET) studies of NF-ĸB with site-specific labeling via ncAA incorporation revealed the conformational dynamics for kinetic control of DNA-binding mediated by IĸBα. Here we report the design and protocols for incorporating the ncAA p-azidophenylalanine (pAzF) into NF-ĸB and site-specific fluorophore labeling with copper-free click chemistry for smFRET. We also expanded the ncAA toolbox of NF-ĸB to include p-benzoylphenylalanine (pBpa) for UV crosslinking mass spectrometry (XL-MS) and incorporated both pAzF and pBpa into the full-length NF-ĸB RelA subunit which includes the intrinsically disordered transactivation domain.
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Affiliation(s)
- Wei Chen
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA.
| | - Tristan R Gunther
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Hannah E R Baughman
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA.
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Saleh AM, VanDyk TG, Jacobson KR, Khan SA, Calve S, Kinzer-Ursem TL. An Integrative Biology Approach to Quantify the Biodistribution of Azidohomoalanine In Vivo. Cell Mol Bioeng 2023; 16:99-115. [PMID: 37096070 PMCID: PMC10121978 DOI: 10.1007/s12195-023-00760-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 02/22/2023] [Indexed: 04/26/2023] Open
Abstract
Background Identification and quantitation of newly synthesized proteins (NSPs) are critical to understanding protein dynamics in development and disease. Probing the nascent proteome can be achieved using non-canonical amino acids (ncAAs) to selectively label the NSPs utilizing endogenous translation machinery, which can then be quantitated with mass spectrometry. We have previously demonstrated that labeling the in vivo murine proteome is feasible via injection of azidohomoalanine (Aha), an ncAA and methionine (Met) analog, without the need for Met depletion. Aha labeling can address biological questions wherein temporal protein dynamics are significant. However, accessing this temporal resolution requires a more complete understanding of Aha distribution kinetics in tissues. Results To address these gaps, we created a deterministic, compartmental model of the kinetic transport and incorporation of Aha in mice. Model results demonstrate the ability to predict Aha distribution and protein labeling in a variety of tissues and dosing paradigms. To establish the suitability of the method for in vivo studies, we investigated the impact of Aha administration on normal physiology by analyzing plasma and liver metabolomes following various Aha dosing regimens. We show that Aha administration induces minimal metabolic alterations in mice. Conclusions Our results demonstrate that we can reproducibly predict protein labeling and that the administration of this analog does not significantly alter in vivo physiology over the course of our experimental study. We expect this model to be a useful tool to guide future experiments utilizing this technique to study proteomic responses to stimuli. Supplementary Information The online version contains supplementary material available at 10.1007/s12195-023-00760-4.
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Affiliation(s)
- Aya M. Saleh
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr, West Lafayette, IN 47906 USA
| | - Tyler G. VanDyk
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr, West Lafayette, IN 47906 USA
| | - Kathryn R. Jacobson
- Purdue University Interdisciplinary Life Science Program, 155 S. Grant Street, West Lafayette, IN 47907 USA
| | - Shaheryar A. Khan
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr, West Lafayette, IN 47906 USA
| | - Sarah Calve
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr, West Lafayette, IN 47906 USA
- Purdue University Interdisciplinary Life Science Program, 155 S. Grant Street, West Lafayette, IN 47907 USA
- Paul M. Rady Department of Mechanical Engineering, University of Colorado – Boulder, 1111 Engineering Center, 427 UCB, Boulder, CO 80309 USA
| | - Tamara L. Kinzer-Ursem
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr, West Lafayette, IN 47906 USA
- Purdue University Interdisciplinary Life Science Program, 155 S. Grant Street, West Lafayette, IN 47907 USA
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Landor LAI, Bratbak G, Larsen A, Tjendra J, Våge S. Differential toxicity of bioorthogonal non-canonical amino acids (BONCAT) in Escherichia coli. J Microbiol Methods 2023; 206:106679. [PMID: 36720393 DOI: 10.1016/j.mimet.2023.106679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/02/2023]
Abstract
Single-cell methods allow studying the activity of single bacterial cells, potentially shedding light on regulatory mechanisms involved in services like biochemical cycling. Bioorthogonal non-canonical amino acid tagging (BONCAT) is a promising method for studying bacterial activity in natural communities, using the methionine analogues L-azidohomoalanine (AHA) and L-homopropargylglycine (HPG) to track protein production in single cells. Both AHA and HPG have been deemed non-toxic, but recent findings suggest that HPG affects bacterial metabolism. In this study we examined the effect of AHA and HPG on Escherichia coli with respect to acute toxicity and growth. E. coli exposed to 5.6-90 μM HPG showed no growth, and the growth rate was significantly reduced at >0.35 μM HPG, compared to the HPG-free control. In contrast, E. coli showed growth at concentrations up to 9 mM AHA. In assays where AHA or HPG were added during the exponential growth phase, the growth sustained but the growth rate was immediately reduced at the highest concentrations (90 μM HPG and 10 mM AHA). Prolonged incubations (20h) with apparently non-toxic concentrations suggest that the cells incorporating NCAAs fail to divide and do not contribute to the next generation resulting in the relative abundance of labelled cells to decrease over time. These results show that HPG and AHA have different impact on the growth of E. coli. Both concentration and incubation time affect the results and need to be considered when designing BONCAT experiments and evaluating results. Time course incubations are suggested as a possible way to obtain more reliable results.
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Affiliation(s)
| | - Gunnar Bratbak
- Department of Biological Sciences, University of Bergen, Norway
| | - Aud Larsen
- NORCE Environment and Climate, Bergen, Norway
| | - Jesslyn Tjendra
- Department of Biological Sciences, University of Bergen, Norway
| | - Selina Våge
- Department of Biological Sciences, University of Bergen, Norway.
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Jiang HK, Tharp JM. Reprogramming Initiator and Nonsense Codons to Simultaneously Install Three Distinct Noncanonical Amino Acids into Proteins in E. coli. Methods Mol Biol 2023; 2676:101-116. [PMID: 37277627 DOI: 10.1007/978-1-0716-3251-2_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Multiple noncanonical amino acids can be installed into proteins in E. coli using mutually orthogonal aminoacyl-tRNA synthetase and tRNA pairs. Here we describe a protocol for simultaneously installing three distinct noncanonical amino acids into proteins for site-specific bioconjugation at three sites. This method relies on an engineered, UAU-suppressing, initiator tRNA, which is aminoacylated with a noncanonical amino acid by Methanocaldococcus jannaschii tyrosyl-tRNA synthetase. Using this initiator tRNA/aminoacyl-tRNA synthetase pair, together with the pyrrolysyl-tRNA synthetase/tRNAPyl pairs from Methanosarcina mazei and Ca. Methanomethylophilus alvus, three noncanonical amino acids can be installed into proteins in response to the UAU, UAG, and UAA codons.
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Affiliation(s)
- Han-Kai Jiang
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT, USA
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Chemical Biology & Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Jeffery M Tharp
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Wang Y, Cai W, Han B, Liu T. Protein Expression with Biosynthesized Noncanonical Amino Acids. Methods Mol Biol 2023; 2676:87-100. [PMID: 37277626 DOI: 10.1007/978-1-0716-3251-2_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Natural proteins are normally made by 20 canonical amino acids. Genetic code expansion (GCE) enables incorporation of diverse chemically synthesized noncanonical amino acids (ncAAs) by orthogonal aminoacyl-tRNA synthetase (aaRS)/tRNA pairs using nonsense codons, which could significantly expand new functionalities of proteins in both scientific and biomedical applications. Here, by hijacking the cysteine biosynthetic enzymes, we describe a method combining amino acid biosynthesis and GCE to introduce around 50 structurally novel ncAAs into proteins by supplementation of commercially available aromatic thiol precursors, thus eliminating the need to chemically synthesize these ncAAs. A screening method is also provided for improving the incorporation efficiency of a particular ncAA. Furthermore, we demonstrate bioorthogonal groups, such as azide and ketone, that are compatible with our system and can be easily introduced into protein for subsequent site-specific labeling.
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Affiliation(s)
- Yong Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Wenkang Cai
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Boyang Han
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China
| | - Tao Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Chemical Biology Center, Department of Molecular and Cellular Pharmacology, Pharmaceutical Sciences, Peking University, Beijing, China.
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Wu Z, Wang J. Genetic Code Expansion in Mammalian Cells. Methods Mol Biol 2023; 2676:159-167. [PMID: 37277631 DOI: 10.1007/978-1-0716-3251-2_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The expansion of the genetic code has enabled the incorporation of noncanonical amino acids (ncAAs) into a defined site of proteins. By introducing such a unique handle into the protein of interest (POI), bioorthogonal reactions can be utilized in live cells to monitor or manipulate the interaction, translocation, function, and modification of the POI. Here, we describe a basic protocol outlining the necessary steps to incorporate a ncAA into a POI in mammalian cells.
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Affiliation(s)
- Zhigang Wu
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, China
| | - Jie Wang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen, China.
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11
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Zheng Z, Xia Q. Noncanonical Amino Acid Incorporation in Mice. Methods Mol Biol 2023; 2676:265-284. [PMID: 37277639 DOI: 10.1007/978-1-0716-3251-2_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Genetic code expansion enables in cellulo biosynthesis of curative proteins with enhanced specificity, improved stability, and even novel functions, due to the incorporation of artificial, designed, noncanonical amino acids (ncAAs). In addition, this orthogonal system also holds great potential for in vivo suppressing nonsense mutations during protein translation, providing an alternative strategy for alleviating inherited diseases caused by premature termination codons (PTCs). Here we describe the approach to explore the therapeutic efficacy and long-term safety of this strategy in transgenic mdx mice with stably expanded genetic codes. Theoretically, this method is applicable to about 11% of monogenic diseases involving nonsense mutations.
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Affiliation(s)
- Zhetao Zheng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Qing Xia
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, China.
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Meineke B, Elsässer SJ. Generation of Amber Suppression Cell Lines Using CRISPR-Cas9. Methods Mol Biol 2023; 2676:169-180. [PMID: 37277632 DOI: 10.1007/978-1-0716-3251-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Genetic code expansion via amber suppression allows cotranslational, site-specific introduction of nonnatural chemical groups into proteins in the living cell. The archaeal pyrrolysine-tRNA/pyrrolysine-tRNA synthetase (PylT/RS) pair from Methanosarcina mazei (Mma) has been established for incorporation of a wide range of noncanonical amino acids (ncAAs) in mammalian cells. Once integrated in an engineered protein, ncAAs allow for simple click-chemistry derivatization, photo-cage control of enzyme activity, and site-specific placement of posttranslational modifications. We previously described a modular amber suppression plasmid system for generating stable cell lines via piggyBac transposition in a range of mammalian cells. Here we detail a general protocol for the generation of CRISPR-Cas9 knock-in cell lines using the same plasmid system. The knock-in strategy relies on CRISPR-Cas9-induced double-strand breaks (DSBs) and nonhomologous end joining (NHEJ) repair to target the PylT/RS expression cassette to the AAVS1 safe harbor locus in human cells. MmaPylRS expression from this single locus is sufficient for efficient amber suppression when the cells are subsequently transfected transiently with a PylT/gene of interest plasmid.
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Affiliation(s)
- Birthe Meineke
- Laboratory of Synthetic and Systems Biology, Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Division of Genome Biology, Karolinska Institutet, Solna, Stockholm, Sweden.
| | - Simon J Elsässer
- Laboratory of Synthetic and Systems Biology, Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Division of Genome Biology, Karolinska Institutet, Solna, Stockholm, Sweden
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13
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Hiefinger C, Mandl S, Wieland M, Kneuttinger A. Rational design, production and in vitro analysis of photoxenoproteins. Methods Enzymol 2023; 682:247-288. [PMID: 36948704 DOI: 10.1016/bs.mie.2022.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In synthetic biology, the artificial control of proteins by light is of growing interest since it enables the spatio-temporal regulation of downstream molecular processes. This precise photocontrol can be established by the site-directed incorporation of photo-sensitive non-canonical amino acids (ncAAs) into proteins, which generates so-called photoxenoproteins. Photoxenoproteins can be engineered using ncAAs that facilitate the irreversible activation or reversible regulation of their activity upon irradiation. In this chapter, we provide a general outline of the engineering process based on the current methodological state-of-the-art to obtain artificial photocontrol in proteins using the ncAAs o-nitrobenzyl-O-tyrosine as example for photocaged ncAAs (irreversible), and phenylalanine-4'-azobenzene as example for photoswitchable ncAAs (reversible). We thereby focus on the initial design as well as the production and characterization of photoxenoproteins in vitro. Finally, we outline the analysis of photocontrol under steady-state and non-steady-state conditions using the allosteric enzyme complexes imidazole glycerol phosphate synthase and tryptophan synthase as examples.
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Affiliation(s)
- Caroline Hiefinger
- Institute of Biophysics and Physical Biochemistry & Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sabrina Mandl
- Institute of Biophysics and Physical Biochemistry & Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Mona Wieland
- Institute of Biophysics and Physical Biochemistry & Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Andrea Kneuttinger
- Institute of Biophysics and Physical Biochemistry & Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany.
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14
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Giri P, Pagar AD, Patil MD, Yun H. Chemical modification of enzymes to improve biocatalytic performance. Biotechnol Adv 2021; 53:107868. [PMID: 34774927 DOI: 10.1016/j.biotechadv.2021.107868] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 12/23/2022]
Abstract
Improvement in intrinsic enzymatic features is in many instances a prerequisite for the scalable applicability of many industrially important biocatalysts. To this end, various strategies of chemical modification of enzymes are maturing and now considered as a distinct way to improve biocatalytic properties. Traditional chemical modification methods utilize reactivities of amine, carboxylic, thiol and other side chains originating from canonical amino acids. On the other hand, noncanonical amino acid- mediated 'click' (bioorthogoal) chemistry and dehydroalanine (Dha)-mediated modifications have emerged as an alternate and promising ways to modify enzymes for functional enhancement. This review discusses the applications of various chemical modification tools that have been directed towards the improvement of functional properties and/or stability of diverse array of biocatalysts.
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Affiliation(s)
- Pritam Giri
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Amol D Pagar
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Mahesh D Patil
- Department of Nanomaterials and Application Technology, Center of Innovative and Applied Bioprocessing (CIAB), Sector-81, PO Manauli, S.A.S. Nagar, Mohali 140306, Punjab, India
| | - Hyungdon Yun
- Department of Systems Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
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15
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Tharp JM, Walker JA, Söll D, Schepartz A. Initiating protein synthesis with noncanonical monomers in vitro and in vivo. Methods Enzymol 2021; 656:495-519. [PMID: 34325796 DOI: 10.1016/bs.mie.2021.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
With few exceptions, ribosomal protein synthesis begins with methionine (or its derivative N-formyl-methionine) across all domains of life. The role of methionine as the initiating amino acid is dictated by the unique structure of its cognate tRNA known as tRNAfMet. By mis-acylating tRNAfMet, we and others have shown that protein synthesis can be initiated with a variety of canonical and noncanonical amino acids both in vitro and in vivo. Furthermore, because the α-amine of the initiating amino acid is not required for peptide bond formation, translation can be initiated with a variety of structurally disparate carboxylic acids that bear little resemblance to traditional α-amino acids. Herein, we provide a detailed protocol to initiate in vitro protein synthesis with substituted benzoic acid and 1,3-dicarbonyl compounds. These moieties are introduced at the N-terminus of peptides by mis-acylated tRNAfMet, prepared by flexizyme-catalyzed tRNA acylation. In addition, we describe a protocol to initiate in vivo protein synthesis with aromatic noncanonical amino acids (ncAAs). This method relies on an engineered chimeric initiator tRNA that is acylated with ncAAs by an orthogonal aminoacyl-tRNA synthetase. Together, these systems are useful platforms for producing N-terminally modified proteins and for engineering the protein synthesis machinery of Escherichia coli to accept additional nonproteinogenic carboxylic acid monomers.
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16
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Galles GD, Infield DT, Mehl RA, Ahern CA. Selection and validation of orthogonal tRNA/synthetase pairs for the encoding of unnatural amino acids across kingdoms. Methods Enzymol 2021; 654:3-18. [PMID: 34120719 DOI: 10.1016/bs.mie.2021.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As an increasing number of protein structures are resolved at atomic and near-atomic resolution, conventional amino acid mutagenesis may be insufficient to test many mechanistic hypotheses. As a result, the development of new tRNA/aminoacyl-tRNA synthetase (aaRS) pairs has become an important tool for determining intricate molecular interactions and understanding protein structures. This chapter describes in detail the directed evolution of new tRNA/aaRS pairs in Escherichia coli for the incorporation of non-canonical amino acids (ncAA). Section 1 describes the selection of new tRNA/aaRS pairs in E. coli. Section 2 details the use of a synthetase to incorporate an ncAA into a mammalian cell line, and Sections 1 and 2 both include methods on the determination of synthetase efficacy and fidelity.
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Affiliation(s)
- Grace D Galles
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, United States; Unnatural Protein Facility, Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States
| | - Daniel T Infield
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, United States
| | - Ryan A Mehl
- Unnatural Protein Facility, Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, IA, United States.
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17
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Abstract
Fluorescence spectroscopy and microscopy are non-destructive methods that provide real-time measurements of ion channel structural dynamics. As such, they constitute a direct path linking the high-resolution structural models from X-ray crystallography and cryo-electron microscopy with the high-resolution functional data from ionic current measurements. The utility of fluorescence as a reporter of channel structure is limited by the palette of available fluorophores. Thiol-reactive fluorophores are small and bright, but are restricted in terms of the positions on a protein that can be labeled and present significant issues with background incorporation. Genetically encoded fluorescent protein tags are specific to a protein of interest, but are very large and usually only used to label the free N- and C-termini of proteins. L-3-(6-acetylnaphthalen-2-ylamino)-2-aminopropionic acid (ANAP) is a fluorescent amino acid that can be specifically incorporated into virtually any site on a protein of interest using amber stop-codon suppression. Due to its environmental sensitivity and potential as a donor in fluorescence resonance energy transfer experiments, it has been adopted by numerous investigators to study voltage, ligand, and temperature-dependent activation of a host of ion channels. Simultaneous measurements of ionic currents and ANAP fluorescence yield exceptional mechanistic insights into channel function. In this chapter, I will summarize the current literature regarding ANAP and ion channels and discuss the practical aspects of using ANAP, including potential pitfalls and confounds.
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18
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Naowarojna N, Cheng R, Lopez J, Wong C, Qiao L, Liu P. Chemical modifications of proteins and their applications in metalloenzyme studies. Synth Syst Biotechnol 2021; 6:32-49. [PMID: 33665390 PMCID: PMC7897936 DOI: 10.1016/j.synbio.2021.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/14/2020] [Accepted: 01/03/2021] [Indexed: 12/21/2022] Open
Abstract
Protein chemical modifications are important tools for elucidating chemical and biological functions of proteins. Several strategies have been developed to implement these modifications, including enzymatic tailoring reactions, unnatural amino acid incorporation using the expanded genetic codes, and recognition-driven transformations. These technologies have been applied in metalloenzyme studies, specifically in dissecting their mechanisms, improving their enzymatic activities, and creating artificial enzymes with non-natural activities. Herein, we summarize some of the recent efforts in these areas with an emphasis on a few metalloenzyme case studies.
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Affiliation(s)
| | | | - Juan Lopez
- Department of Chemistry, Boston University, Boston, MA, 02215, United States
| | - Christina Wong
- Department of Chemistry, Boston University, Boston, MA, 02215, United States
| | - Lu Qiao
- Department of Chemistry, Boston University, Boston, MA, 02215, United States
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, MA, 02215, United States
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19
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Abstract
Lysine acetylation is a ubiquitous modification permeating the proteomes of organisms from all domains of life. Lysine deacetylases (KDACs) reverse this modification by following two fundamentally different enzymatic mechanisms, which differ mainly by the need for NAD+ as stoichiometric co-substrate. KDACs are often found as catalytic subunit in protein complexes involved in cell cycle regulation, chromatin organization and transcription. Their promiscuity with respect to sequence context and type of lysine acylation convolutes the network of functional and physical connections.Here we present an efficient selection method for KDACs in E. coli, which allows for the creation of acyl-type specific KDAC variants, which greatly facilitate the investigation of their physiological function . The selection system builds on the incorporation of acylated lysines by genetic code expansion in reporter enzymes with essential lysine residues. We describe the creation of KDAC mutant libraries by saturation mutagenesis of active site residues, the isolation of individual mutants from this library using the selection system, and their biochemical characterization with acylated firefly luciferase.
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Affiliation(s)
- Martin Spinck
- Department of Structural Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - Maria Ecke
- Department of Structural Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - Damian Schiller
- Department of Structural Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - Heinz Neumann
- Department of Structural Biochemistry, Max-Planck-Institute of Molecular Physiology, Dortmund, Germany.
- Department of Chemical Engineering and Biotechnology, University of Applied Sciences, Darmstadt, Germany.
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20
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Zambaldo C, Koh M, Nasertorabi F, Han GW, Chatterjee A, Stevens RC, Schultz PG. An orthogonal seryl-tRNA synthetase/tRNA pair for noncanonical amino acid mutagenesis in Escherichia coli. Bioorg Med Chem 2020; 28:115662. [PMID: 33069069 DOI: 10.1016/j.bmc.2020.115662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/18/2020] [Indexed: 11/24/2022]
Abstract
We report the development of the orthogonal amber-suppressor pair Archaeoglobus fulgidus seryl-tRNA (Af-tRNASer)/Methanosarcina mazei seryl-tRNA synthetase (MmSerRS) in Escherichia coli. Furthermore, the crystal structure of MmSerRS was solved at 1.45 Å resolution, which should enable structure-guided engineering of its active site to genetically encode small, polar noncanonical amino acids (ncAAs).
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21
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Zemella A, Richter T, Thoring L, Kubick S. A Combined Cell-Free Protein Synthesis and Fluorescence-Based Approach to Investigate GPCR Binding Properties. Methods Mol Biol 2019; 1947:57-77. [PMID: 30969411 DOI: 10.1007/978-1-4939-9121-1_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fluorescent labeling of de novo synthesized proteins is in particular a valuable tool for functional and structural studies of membrane proteins. In this context, we present two methods for the site-specific fluorescent labeling of difficult-to-express membrane proteins in combination with cell-free protein synthesis. The cell-free protein synthesis system is based on Chinese Hamster Ovary Cells (CHO) since this system contains endogenous membrane structures derived from the endoplasmic reticulum. These so-called microsomes enable a direct integration of membrane proteins into a biological membrane. In this protocol the first part describes the fluorescent labeling by using a precharged tRNA, loaded with a fluorescent amino acid. The second part describes the preparation of a modified aminoacyl-tRNA-synthetase and a suppressor tRNA that are applied to the CHO cell-free system to enable the incorporation of a non-canonical amino acid. The reactive group of the non-canonical amino acid is further coupled to a fluorescent dye. Both methods utilize the amber stop codon suppression technology. The successful fluorescent labeling of the model G protein-coupled receptor adenosine A2A (Adora2a) is analyzed by in-gel-fluorescence, a reporter protein assay, and confocal laser scanning microscopy (CLSM). Moreover, a ligand-dependent conformational change of the fluorescently labeled Adora2a was analyzed by bioluminescence resonance energy transfer (BRET).
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22
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Zou H, Li L, Zhang T, Shi M, Zhang N, Huang J, Xian M. Biosynthesis and biotechnological application of non-canonical amino acids: Complex and unclear. Biotechnol Adv 2018; 36:1917-1927. [PMID: 30063950 DOI: 10.1016/j.biotechadv.2018.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/22/2018] [Accepted: 07/27/2018] [Indexed: 01/05/2023]
Abstract
Compared with the better-studied canonical amino acids, the distribution, metabolism and functions of natural non-canonical amino acids remain relatively obscure. Natural non-canonical amino acids have been mainly discovered in plants as secondary metabolites that perform diversified physiological functions. Due to their specific characteristics, a broader range of natural and artificial non-canonical amino acids have recently been applied in the development of functional materials and pharmaceutical products. With the rapid development of advanced methods in biotechnology, non-canonical amino acids can be incorporated into peptides, proteins and enzymes to improve the function and performance relative to their natural counterparts. Therefore, biotechnological application of non-canonical amino acids in artificial bio-macromolecules follows the central goal of synthetic biology to: create novel life forms and functions. However, many of the non-canonical amino acids are synthesized via chemo- or semi-synthetic methods, and few non-canonical amino acids can be synthesized using natural in vivo pathways. Therefore, further research is needed to clarify the metabolic pathways and key enzymes of the non-canonical amino acids. This will lead to the discovery of more candidate non-canonical amino acids, especially for those that are derived from microorganisms and are naturally bio-compatible with chassis strains for in vivo biosynthesis. In this review, we summarize representative natural and artificial non-canonical amino acids, their known information regarding associated metabolic pathways, their characteristics and their practical applications. Moreover, this review summarizes current barriers in developing in vivo pathways for the synthesis of non-canonical amino acids, as well as other considerations, future trends and potential applications of non-canonical amino acids in advanced biotechnology.
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Affiliation(s)
- Huibin Zou
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China; CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
| | - Lei Li
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Tongtong Zhang
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Mengxun Shi
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Nan Zhang
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Jingling Huang
- College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China
| | - Mo Xian
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
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23
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Schmidt M, Pei L, Budisa N. Xenobiology: State-of-the-Art, Ethics, and Philosophy of New-to-Nature Organisms. Adv Biochem Eng Biotechnol 2018; 162:301-315. [PMID: 28567486 DOI: 10.1007/10_2016_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The basic chemical constitution of all living organisms in the context of carbon-based chemistry consists of a limited number of small molecules and polymers. Until the twenty-first century, biology was mainly an analytical science and has now reached a point where it merges with engineering science, paving the way for synthetic biology. One of the objectives of synthetic biology is to try to change the chemical compositions of living cells, that is, to create an artificial biological diversity, which in turn fosters a new sub-field of synthetic biology, xenobiology. In particular, the genetic code in living systems is based on highly standardized chemistry composed of the same "letters" or nucleotides as informational polymers (DNA, RNA) and the 20 amino acids which serve as basic building blocks for proteins. The universality of the genetic code enables not only vertical gene transfer within the same species but also horizontal gene transfer across biological taxa, which require a high degree of standardization and interconnectivity. Although some minor alterations of the standard genetic code are found in nature (e.g., proteins containing non-conical amino acids exist in nature, and some organisms use alternated coding systems), all structurally deep chemistry changes within living systems are generally lethal, making the creation of artificial biological system an extremely difficult challenge.In this context, one of the great challenges for bioscience is the development of a strategy for expanding the standard basic chemical repertoire of living cells. Attempts to alter the meaning of the genetic information stored in DNA as an informational polymer by changing the chemistry of the polymer (i.e., xeno-nucleic acids) or by changes in the genetic code have already yielded successful results. In the future this should enable the partial or full redirection of the biological information flow to generate "new" version(s) of the genetic code derived from the "old" biological world.In addition to the scientific challenges, the attempt to increase biochemical diversity also raises important ethical and philosophical issues. Although promotors of this branch of synthetic biology highlight the many potential applications to come (e.g., novel tools for diagnostics and fighting infection diseases), such developments could also bring risks affecting social, political, and other structures of nearly all societies.
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Affiliation(s)
- Markus Schmidt
- Biofaction KG, Kundmanngasse 39/12, Vienna, 1030, Austria.
| | - Lei Pei
- Biofaction KG, Kundmanngasse 39/12, Vienna, 1030, Austria
| | - Nediljko Budisa
- AK Biokatalyse, Institut für Chemie, Technische Universität Berlin, Müller-Breslau-Straße 10, 10623, Berlin, Germany
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24
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Abstract
Non-canonical amino acids are finding increasing use in basic and applied research. Proteins that evolved naturally for biological function did so by exploiting the chemistries of the canonical amino acids; however, when proteins are repurposed for biomedical and pharmacological applications, they are often subject to conditions different from those characteristic of their original biological environments. Non-canonical amino acids can impart properties that are inaccessible within canonical protein sequence space, and can thereby lead to improved or new functionality. We describe simple methods for global replacement of canonical amino acids by their non-canonical counterparts in recombinant proteins made in high yield in bacterial expression hosts. These methods can be used to engineer both chemical and physical properties of recombinant proteins.
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Affiliation(s)
- Katharine Y Fang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Seth A Lieblich
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA
| | - David A Tirrell
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, USA.
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25
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Abstract
Pyrrolysine is the 22nd proteinogenic amino acid encoded into proteins in response to amber (TAG) codons in a small number of archaea and bacteria. The incorporation of pyrrolysine is facilitated by a specialized aminoacyl-tRNA synthetase (PylRS) and its cognate tRNA (tRNAPyl). The secondary structure of tRNAPyl contains several unique features not found in canonical tRNAs. Numerous studies have demonstrated that the PylRS/tRNAPyl pair from archaea is orthogonal in E. coli and eukaryotic hosts, which has led to the widespread use of this pair for the genetic incorporation of non-canonical amino acids. In this brief review we examine the work that has been done to elucidate the structure of tRNAPyl, its interaction with PylRS, and survey recent progress on the use of tRNAPyl as a tool for genetic code expansion.
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Affiliation(s)
- Jeffery M Tharp
- a Department of Chemistry , Texas A&M University , College Station , TX , USA
| | - Andreas Ehnbom
- a Department of Chemistry , Texas A&M University , College Station , TX , USA
| | - Wenshe R Liu
- a Department of Chemistry , Texas A&M University , College Station , TX , USA
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Post MR, Tender GS, Lester HA, Dougherty DA. Secondary Ammonium Agonists Make Dual Cation-π Interactions in α4β2 Nicotinic Receptors. eNeuro 2017; 4:ENEURO. [PMID: 28589175 DOI: 10.1523/ENEURO.0032-17.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 11/21/2022] Open
Abstract
A cation-π interaction between the ammonium group of an agonist and a conserved tryptophan termed TrpB is a near universal feature of agonist binding to nicotinic acetylcholine receptors (nAChRs). TrpB is one of five residues that form the aromatic box of the agonist binding site, and for the prototype agonists ACh and nicotine, only TrpB makes a functional cation-π interaction. We report that, in addition to TrpB, a significant cation-π interaction is made to a second aromatic, TyrC2, by the agonists metanicotine, TC299423, varenicline, and nornicotine. A common structural feature of these agonists, and a distinction from ACh and nicotine, is a protonated secondary amine that provides the cation for the cation-π interaction. These results indicate a distinction in binding modes between agonists with subtly different structures that may provide guidance for the development of subtype-selective agonists of nAChRs.
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Reynolds NM, Vargas-Rodriguez O, Söll D, Crnković A. The central role of tRNA in genetic code expansion. Biochim Biophys Acta Gen Subj 2017; 1861:3001-3008. [PMID: 28323071 DOI: 10.1016/j.bbagen.2017.03.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/14/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND The development of orthogonal translation systems (OTSs) for genetic code expansion (GCE) has allowed for the incorporation of a diverse array of non-canonical amino acids (ncAA) into proteins. Transfer RNA, the central molecule in the translation of the genetic message into proteins, plays a significant role in the efficiency of ncAA incorporation. SCOPE OF REVIEW Here we review the biochemical basis of OTSs for genetic code expansion. We focus on the role of tRNA and discuss strategies used to engineer tRNA for the improvement of ncAA incorporation into proteins. MAJOR CONCLUSIONS The engineering of orthogonal tRNAs for GCE has significantly improved the incorporation of ncAAs. However, there are numerous unintended consequences of orthogonal tRNA engineering that cannot be predicted ab initio. GENERAL SIGNIFICANCE Genetic code expansion has allowed for the incorporation of a great diversity of ncAAs and novel chemistries into proteins, making significant contributions to our understanding of biological molecules and interactions. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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Affiliation(s)
- Noah M Reynolds
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA; Department of Chemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Ana Crnković
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
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28
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Englert M, Vargas-Rodriguez O, Reynolds NM, Wang YS, Söll D, Umehara T. A genomically modified Escherichia coli strain carrying an orthogonal E. coli histidyl-tRNA synthetase•tRNA His pair. Biochim Biophys Acta Gen Subj 2017; 1861:3009-3015. [PMID: 28288813 DOI: 10.1016/j.bbagen.2017.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/01/2017] [Indexed: 01/23/2023]
Abstract
BACKGROUND Development of new aminoacyl-tRNA synthetase (aaRS)•tRNA pairs is central for incorporation of novel non-canonical amino acids (ncAAs) into proteins via genetic code expansion (GCE). The Escherichia coli and Caulobacter crescentus histidyl-tRNA synthetases (HisRS) evolved divergent mechanisms of tRNAHis recognition that prevent their cross-reactivity. Although the E. coli HisRS•tRNAHis pair is a good candidate for GCE, its use in C. crescentus is limited by the lack of established genetic selection methods and by the low transformation efficiency of C. crescentus. METHODS E. coli was genetically engineered to use a C. crescentus HisRS•tRNAHis pair. Super-folder green fluorescent protein (sfGFP) and chloramphenicol acetyltransferase (CAT) were used as reporters for read-through assays. A library of 313 ncAAs coupled with the sfGFP reporter system was employed to investigate the specificity of E. coli HisRS in vivo. RESULTS A genomically modified E. coli strain (named MEOV1) was created. MEVO1 requires an active C. crescentus HisRS•tRNAHis pair for growth, and displays a similar doubling time as the parental E. coli strain. sfGFP- and CAT-based assays showed that the E. coli HisRS•tRNAHis pair is orthogonal in MEOV1 cells. A mutation in the anticodon loop of E. coli tRNAHisCUA elevated its suppression efficiency by 2-fold. CONCLUSIONS The C. crescentus HisRS•tRNAHis pair functionally complements an E. coli ΔhisS strain. The E. coli HisRS•tRNAHis is orthogonal in MEOV1 cells. E. coli tRNAHisCUA is an efficient amber suppressor in MEOV1. GENERAL SIGNIFICANCE We developed a platform that allows protein engineering of E. coli HisRS that should facilitate GCE in E. coli. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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Affiliation(s)
- Markus Englert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Oscar Vargas-Rodriguez
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Noah M Reynolds
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Yane-Shih Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Dieter Söll
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Chemistry, Yale University, New Haven, CT 06520, USA.
| | - Takuya Umehara
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
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Völler JS, Biava H, Hildebrandt P, Budisa N. An expanded genetic code for probing the role of electrostatics in enzyme catalysis by vibrational Stark spectroscopy. Biochim Biophys Acta Gen Subj 2017; 1861:3053-3059. [PMID: 28229928 DOI: 10.1016/j.bbagen.2017.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/03/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND To find experimental validation for electrostatic interactions essential for catalytic reactions represents a challenge due to practical limitations in assessing electric fields within protein structures. SCOPE OF REVIEW This review examines the applications of non-canonical amino acids (ncAAs) as genetically encoded probes for studying the role of electrostatic interactions in enzyme catalysis. MAJOR CONCLUSIONS ncAAs constitute sensitive spectroscopic probes to detect local electric fields by exploiting the vibrational Stark effect (VSE) and thus have the potential to map the protein electrostatics. GENERAL SIGNIFICANCE Mapping the electrostatics in proteins will improve our understanding of natural catalytic processes and, in beyond, will be helpful for biocatalyst engineering. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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Affiliation(s)
- Jan-Stefan Völler
- Department of Chemistry, Technische Universität Berlin, Müller-Breslau-Strasse 10, D-10623 Berlin, Germany.
| | - Hernan Biava
- Department of Chemistry, Technische Universität Berlin, Müller-Breslau-Strasse 10, D-10623 Berlin, Germany; Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany.
| | - Nediljko Budisa
- Department of Chemistry, Technische Universität Berlin, Müller-Breslau-Strasse 10, D-10623 Berlin, Germany.
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Adumeau P, Sharma SK, Brent C, Zeglis BM. Site-Specifically Labeled Immunoconjugates for Molecular Imaging--Part 2: Peptide Tags and Unnatural Amino Acids. Mol Imaging Biol 2016; 18:153-65. [PMID: 26754791 DOI: 10.1007/s11307-015-0920-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular imaging using radioisotope- or fluorophore-labeled antibodies is increasingly becoming a critical component of modern precision medicine. Yet despite this promise, the vast majority of these immunoconjugates are synthesized via the random coupling of amine-reactive bifunctional probes to lysines within the antibody, a process that can result in heterogeneous and poorly defined constructs with suboptimal pharmacological properties. In an effort to circumvent these issues, the last 5 years have played witness to a great deal of research focused on the creation of effective strategies for the site-specific attachment of payloads to antibodies. These chemoselective modification methods yield immunoconjugates that are more homogenous and better defined than constructs created using traditional synthetic approaches. Moreover, site-specifically labeled immunoconjugates have also been shown to exhibit superior in vivo behavior compared to their randomly modified cousins. The over-arching goal of this two-part review is to provide a broad yet detailed account of the various site-specific bioconjugation approaches that have been used to create immunoconjugates for positron emission tomography (PET), single photon emission computed tomography (SPECT), and fluorescence imaging. In Part 1, we covered site-specific bioconjugation techniques based on the modification of cysteine residues and the chemoenzymatic manipulation of glycans. In Part 2, we will detail two families of bioconjugation approaches that leverage biochemical tools to achieve site-specificity. First, we will discuss modification methods that employ peptide tags either as sites for enzyme-catalyzed ligations or as radiometal coordination architectures. And second, we will examine bioconjugation strategies predicated on the incorporation of unnatural or non-canonical amino acids into antibodies via genetic engineering. Finally, we will compare the advantages and disadvantages of the modification strategies covered in both parts of the review and offer a brief discussion of the overall direction of the field.
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Affiliation(s)
- Pierre Adumeau
- Department of Chemistry and Biochemistry, Hunter College and the Graduate Center of the City University of New York, 413 East 69th Street, New York, NY, 10021, USA
| | - Sai Kiran Sharma
- Department of Chemistry and Biochemistry, Hunter College and the Graduate Center of the City University of New York, 413 East 69th Street, New York, NY, 10021, USA
| | - Colleen Brent
- Department of Chemistry and Biochemistry, Hunter College and the Graduate Center of the City University of New York, 413 East 69th Street, New York, NY, 10021, USA
| | - Brian M Zeglis
- Department of Chemistry and Biochemistry, Hunter College and the Graduate Center of the City University of New York, 413 East 69th Street, New York, NY, 10021, USA. .,Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY, 10065, USA.
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31
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Zhou L, Shao J, Li Q, van Heel AJ, de Vries MP, Broos J, Kuipers OP. Incorporation of tryptophan analogues into the lantibiotic nisin. Amino Acids 2016; 48:1309-18. [PMID: 26872656 DOI: 10.1007/s00726-016-2186-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 01/22/2016] [Indexed: 11/08/2022]
Abstract
Lantibiotics are posttranslationally modified peptides with efficient inhibitory activity against various Gram-positive bacteria. In addition to the original modifications, incorporation of non-canonical amino acids can render new properties and functions to lantibiotics. Nisin is the most studied lantibiotic and contains no tryptophan residues. In this study, a system was constructed to incorporate tryptophan analogues into nisin, which included the modification machinery (NisBTC) and the overexpression of tryptophanyl-tRNA synthetase (TrpRS). Tryptophan and three different tryptophan analogues (5-fluoroTrp (5FW), 5-hydroxyTrp (5HW) and 5-methylTrp (5MeW)) were successfully incorporated at four different positions of nisin (I1W, I4W, M17W and V32W). The incorporation efficiency of tryptophan analogues into mutants I1W, M17W and V32W was over 97 %, while the mutant I4W showed relatively low incorporation efficiency (69–93 %). The variants with 5FW showed relatively higher production yield, while 5MeW-containing variants showed the lowest yield. The dehydration efficiency of serines or threonines was affected by the tryptophan mutants of I4W and V32W. The affinity of the peptides for the cation-ion exchange and reverse phase chromatography columns was significantly reduced when 5HW was incorporated. The antimicrobial activity of IIW and its 5FW analogue both decreased two times compared to that of nisin, while that of its 5HW analogue decreased four times. The 5FW analogue of I4W also showed two times decreased activity than nisin. However, the mutant M17W and its 5HW analogue both showed 32 times reduced activity relative to that of nisin.
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Post MR, Limapichat W, Lester HA, Dougherty DA. Heterologous expression and nonsense suppression provide insights into agonist behavior at α6β2 nicotinic acetylcholine receptors. Neuropharmacology 2015; 97:376-82. [PMID: 25908401 DOI: 10.1016/j.neuropharm.2015.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/27/2015] [Accepted: 04/10/2015] [Indexed: 10/23/2022]
Abstract
The α6-containing subtypes of the nicotinic acetylcholine receptor (nAChR) are localized to presynaptic terminals of the dopaminergic pathways of the central nervous system. Selective ligands for these nAChRs are potentially useful in both Parkinson's disease and addiction. For these and other goals, it is important to distinguish the binding behavior of agonists at the α6-β2 binding site versus other subtypes. To study this problem, we apply nonsense suppression-based non-canonical amino acid mutagenesis. We report a combination of four mutations in α6β2 that yield high-level heterologous expression in Xenopus oocytes. By varying mRNA injection ratios, two populations were observed with unique characteristics, likely due to differing stoichiometries. Responses to nine known nAChR agonists were analyzed at the receptor, and their corresponding EC50 values and efficacies are reported. The system is compatible with nonsense suppression, allowing structure-function studies between Trp149 - a conserved residue on loop B found to make a cation-π interaction at several nAChR subtypes - and several agonists. These studies reveal that acetylcholine forms a strong cation-π interaction with the conserved tryptophan, while nicotine and TC299423 do not, suggesting a unique pharmacology for the α6β2 nAChR.
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Affiliation(s)
- Michael R Post
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Walrati Limapichat
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA
| | - Henry A Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Dennis A Dougherty
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125, USA.
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Wan W, Tharp JM, Liu WR. Pyrrolysyl-tRNA synthetase: an ordinary enzyme but an outstanding genetic code expansion tool. Biochim Biophys Acta 2014; 1844:1059-70. [PMID: 24631543 DOI: 10.1016/j.bbapap.2014.03.002] [Citation(s) in RCA: 280] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/01/2014] [Accepted: 03/05/2014] [Indexed: 11/16/2022]
Abstract
The genetic incorporation of the 22nd proteinogenic amino acid, pyrrolysine (Pyl) at amber codon is achieved by the action of pyrrolysyl-tRNA synthetase (PylRS) together with its cognate tRNA(Pyl). Unlike most aminoacyl-tRNA synthetases, PylRS displays high substrate side chain promiscuity, low selectivity toward its substrate α-amine, and low selectivity toward the anticodon of tRNA(Pyl). These unique but ordinary features of PylRS as an aminoacyl-tRNA synthetase allow the Pyl incorporation machinery to be easily engineered for the genetic incorporation of more than 100 non-canonical amino acids (NCAAs) or α-hydroxy acids into proteins at amber codon and the reassignment of other codons such as ochre UAA, opal UGA, and four-base AGGA codons to code NCAAs.
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Affiliation(s)
- Wei Wan
- Department of Chemistry, Texas A&M University, College Station, TX 77845, USA
| | - Jeffery M Tharp
- Department of Chemistry, Texas A&M University, College Station, TX 77845, USA
| | - Wenshe R Liu
- Department of Chemistry, Texas A&M University, College Station, TX 77845, USA.
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