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Daniilidis M, Sperl LE, Müller BS, Babl A, Hagn F. Efficient Segmental Isotope Labeling of Integral Membrane Proteins for High-Resolution NMR Studies. J Am Chem Soc 2024; 146:15403-15410. [PMID: 38787792 PMCID: PMC11157531 DOI: 10.1021/jacs.4c03294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
High-resolution structural NMR analyses of membrane proteins are challenging due to their large size, resulting in broad resonances and strong signal overlap. Among the isotope labeling methods that can remedy this situation, segmental isotope labeling is a suitable strategy to simplify NMR spectra and retain high-resolution structural information. However, protein ligation within integral membrane proteins is complicated since the hydrophobic protein fragments are insoluble, and the removal of ligation side-products is elaborate. Here, we show that a stabilized split-intein system can be used for rapid and high-yield protein trans-splicing of integral membrane proteins under denaturing conditions. This setup enables segmental isotope labeling experiments within folded protein domains for NMR studies. We show that high-quality NMR spectra of markedly reduced complexity can be obtained in detergent micelles and lipid nanodiscs. Of note, the nanodisc insertion step specifically selects for the ligated and correctly folded membrane protein and simultaneously removes ligation byproducts. Using this tailored workflow, we show that high-resolution NMR structure determination is strongly facilitated with just two segmentally isotope-labeled membrane protein samples. The presented method will be broadly applicable to structural and dynamical investigations of (membrane-) proteins and their complexes by solution and solid-state NMR but also other structural methods where segmental labeling is beneficial.
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Affiliation(s)
- Melina Daniilidis
- Bavarian
NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
| | - Laura E. Sperl
- Bavarian
NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
| | - Benedikt S. Müller
- Bavarian
NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
| | - Antonia Babl
- Bavarian
NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
| | - Franz Hagn
- Bavarian
NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85748 Garching, Germany
- Institute
of Structural Biology, Helmholtz Munich, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
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2
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Berkeley RF, Debelouchina GT. Chemical tools for study and modulation of biomolecular phase transitions. Chem Sci 2022; 13:14226-14245. [PMID: 36545140 PMCID: PMC9749140 DOI: 10.1039/d2sc04907d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 11/21/2022] [Indexed: 11/23/2022] Open
Abstract
Biomolecular phase transitions play an important role in organizing cellular processes in space and time. Methods and tools for studying these transitions, and the intrinsically disordered proteins (IDPs) that often drive them, are typically less developed than tools for studying their folded protein counterparts. In this perspective, we assess the current landscape of chemical tools for studying IDPs, with a specific focus on protein liquid-liquid phase separation (LLPS). We highlight methodologies that enable imaging and spectroscopic studies of these systems, including site-specific labeling with small molecules and the diverse range of capabilities offered by inteins and protein semisynthesis. We discuss strategies for introducing post-translational modifications that are central to IDP and LLPS function and regulation. We also investigate the nascent field of noncovalent small-molecule modulators of LLPS. We hope that this review of the state-of-the-art in chemical tools for interrogating IDPs and LLPS, along with an associated perspective on areas of unmet need, can serve as a valuable and timely resource for these rapidly expanding fields of study.
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Affiliation(s)
- Raymond F. Berkeley
- Department of Chemistry and Biochemistry, University of California San DiegoLa JollaCAUSA
| | - Galia T. Debelouchina
- Department of Chemistry and Biochemistry, University of California San DiegoLa JollaCAUSA
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3
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Clark ET, Sievers EE, Debelouchina GT. A Chemical Biology Primer for NMR Spectroscopists. JOURNAL OF MAGNETIC RESONANCE OPEN 2022; 10-11:100044. [PMID: 35494416 PMCID: PMC9053072 DOI: 10.1016/j.jmro.2022.100044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Among structural biology techniques, NMR spectroscopy offers unique capabilities that enable the atomic resolution studies of dynamic and heterogeneous biological systems under physiological and native conditions. Complex biological systems, however, often challenge NMR spectroscopists with their low sensitivity, crowded spectra or large linewidths that reflect their intricate interaction patterns and dynamics. While some of these challenges can be overcome with the development of new spectroscopic approaches, chemical biology can also offer elegant and efficient solutions at the sample preparation stage. In this tutorial, we aim to present several chemical biology tools that enable the preparation of selectively and segmentally labeled protein samples, as well as the introduction of site-specific spectroscopic probes and post-translational modifications. The four tools covered here, namely cysteine chemistry, inteins, native chemical ligation, and unnatural amino acid incorporation, have been developed and optimized in recent years to be more efficient and applicable to a wider range of proteins than ever before. We briefly introduce each tool, describe its advantages and disadvantages in the context of NMR experiments, and offer practical advice for sample preparation and analysis. We hope that this tutorial will introduce beginning researchers in the field to the possibilities chemical biology can offer to NMR spectroscopists, and that it will inspire new and exciting applications in the quest to understand protein function in health and disease.
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Affiliation(s)
- Evan T. Clark
- Department of Chemistry and Biochemistry, Division of Physical Sciences, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Elanor E. Sievers
- Department of Chemistry and Biochemistry, Division of Physical Sciences, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Galia T. Debelouchina
- Department of Chemistry and Biochemistry, Division of Physical Sciences, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Corresponding author: Galia Debelouchina, University of California, San Diego, Natural Sciences Building 4322, 9500 Gilman Dr., La Jolla, CA 92093, 858-534-3038,
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4
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Heikkinen HA, Aranko AS, Iwaï H. The NMR structure of the engineered halophilic DnaE intein for segmental isotopic labeling using conditional protein splicing. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 338:107195. [PMID: 35398651 DOI: 10.1016/j.jmr.2022.107195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 03/02/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
Protein trans-splicing catalyzed by split inteins has been used for segmental isotopic labeling of proteins for alleviating the complexity of NMR signals. Whereas inteins spontaneously trigger protein splicing upon protein folding, inteins from extremely halophilic organisms require a high salinity condition to induce protein splicing. We designed and created a salt-inducible intein from the widely used DnaE intein from Nostoc punctiforme by introducing 29 mutations, which required a lower salt concentration than naturally occurring halo-obligate inteins. We determined the NMR solution structure of the engineered salt-inducible DnaE intein in 2 M NaCl, showing the essentially identical three-dimensional structure to the original one, albeit it unfolds without salts. The NMR structure of a halo-obligate intein under high salinity suggests that the stabilization of the active folded conformation is not a mere result of various intramolecular interactions but the subtle energy balance from the complex interactions, including the solvation energy, which involve waters, ions, co-solutes, and protein polypeptide chains.
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Affiliation(s)
- Harri A Heikkinen
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland
| | - A Sesilja Aranko
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland.
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland.
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5
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Development of ULYSSIS, a Tool for the Biosynthesis of Cyclotides and Cyclic Knottins. Int J Pept Res Ther 2021. [DOI: 10.1007/s10989-021-10336-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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6
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Camporesi G, Minzoni A, Morasso L, Ciurli S, Musiani F. Nickel import and export in the human pathogen Helicobacter pylori, perspectives from molecular modelling. Metallomics 2021; 13:6427379. [PMID: 34791340 DOI: 10.1093/mtomcs/mfab066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/11/2021] [Indexed: 12/11/2022]
Abstract
The uptake of essential metal ions and the ability to extrude them when their excess causes toxicity are crucial processes for all living beings. Nickel is a virulence factor for several human pathogens and in particular for the human gastric pathogen Helicobacter pylori because of its crucial role in the catalytic activity of two Ni-dependent enzymes, urease and hydrogenase. H. pylori requires efficient uptake mechanisms to import Ni(II) because of its scarcity in the human body, but the molecular details of Ni(II) homeostasis are not fully known. Here we offer a structural framework for the machinery of Ni(II) import/export in H. pylori, obtained through comparative modelling and macromolecular docking. The model structures reported in this perspective are initial steps towards the understanding of these processes at the molecular level and in the direction to exploit them to eradicate infections caused by this family of pathogens. The differences between the structural models obtained by using both the recently released neural network-based approach implemented in AlphaFold2 and a more classical user-driven modelling procedure are also discussed.
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Affiliation(s)
- Giulia Camporesi
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, I-40127 Bologna, Italy
| | - Arianna Minzoni
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, I-40127 Bologna, Italy
| | - Luca Morasso
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, I-40127 Bologna, Italy
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, I-40127 Bologna, Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, I-40127 Bologna, Italy
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7
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Ackermann BE, Debelouchina GT. Emerging Contributions of Solid-State NMR Spectroscopy to Chromatin Structural Biology. Front Mol Biosci 2021; 8:741581. [PMID: 34708075 PMCID: PMC8544521 DOI: 10.3389/fmolb.2021.741581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
The eukaryotic genome is packaged into chromatin, a polymer of DNA and histone proteins that regulates gene expression and the spatial organization of nuclear content. The repetitive character of chromatin is diversified into rich layers of complexity that encompass DNA sequence, histone variants and post-translational modifications. Subtle molecular changes in these variables can often lead to global chromatin rearrangements that dictate entire gene programs with far reaching implications for development and disease. Decades of structural biology advances have revealed the complex relationship between chromatin structure, dynamics, interactions, and gene expression. Here, we focus on the emerging contributions of magic-angle spinning solid-state nuclear magnetic resonance spectroscopy (MAS NMR), a relative newcomer on the chromatin structural biology stage. Unique among structural biology techniques, MAS NMR is ideally suited to provide atomic level information regarding both the rigid and dynamic components of this complex and heterogenous biological polymer. In this review, we highlight the advantages MAS NMR can offer to chromatin structural biologists, discuss sample preparation strategies for structural analysis, summarize recent MAS NMR studies of chromatin structure and dynamics, and close by discussing how MAS NMR can be combined with state-of-the-art chemical biology tools to reconstitute and dissect complex chromatin environments.
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Affiliation(s)
| | - Galia T. Debelouchina
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, United States
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8
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The Inducible Intein-Mediated Self-Cleaving Tag (IIST) System: A Novel Purification and Amidation System for Peptides and Proteins. Molecules 2021; 26:molecules26195948. [PMID: 34641492 PMCID: PMC8512742 DOI: 10.3390/molecules26195948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 12/12/2022] Open
Abstract
An efficient self-cleavable purification tag could be a powerful tool for purifying recombinant proteins and peptides without additional proteolytic processes using specific proteases. Thus, the intein-mediated self-cleavage tag was developed and has been commercially available as the IMPACT™ system. However, uncontrolled cleavages of the purification tag by the inteins in the IMPACT™ system have been reported, thereby reducing final yields. Therefore, controlling the protein-splicing activity of inteins has become critical. Here we utilized conditional protein splicing by salt conditions. We developed the inducible intein-mediated self-cleaving tag (IIST) system based on salt-inducible protein splicing of the MCM2 intein from the extremely halophilic archaeon, Halorhabdus utahensis and applied it to small peptides. Moreover, we described a method for the amidation using the same IIST system and demonstrated 15N-labeling of the C-terminal amide group of a single domain antibody (VHH).
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Tang TMS, Luk LYP. Asparaginyl endopeptidases: enzymology, applications and limitations. Org Biomol Chem 2021; 19:5048-5062. [PMID: 34037066 PMCID: PMC8209628 DOI: 10.1039/d1ob00608h] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/12/2021] [Indexed: 12/15/2022]
Abstract
Asparaginyl endopeptidases (AEP) are cysteine proteases found in mammalian and plant cells. Several AEP isoforms from plant species were found to exhibit transpeptidase activity which is integral for the key head-to-tail cyclisation reaction during the biosynthesis of cyclotides. Since many plant AEPs exhibit excellent enzyme kinetics for peptide ligation via a relatively short substrate recognition sequence, they have become appealing tools for peptide and protein modification. In this review, research focused on the enzymology of AEPs and their applications in polypeptide cyclisation and labelling will be presented. Importantly, the limitations of using AEPs and opportunities for future research and innovation will also be discussed.
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Affiliation(s)
- T M Simon Tang
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
| | - Louis Y P Luk
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK. and Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
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10
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Dyson HJ, Wright PE. NMR illuminates intrinsic disorder. Curr Opin Struct Biol 2021; 70:44-52. [PMID: 33951592 DOI: 10.1016/j.sbi.2021.03.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023]
Abstract
Nuclear magnetic resonance (NMR) has long been instrumental in the characterization of intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs). This method continues to offer rich insights into the nature of IDPs in solution, especially in combination with other biophysical methods such as small-angle scattering, single-molecule fluorescence, electron paramagnetic resonance (EPR), and mass spectrometry. Substantial advances have been made in recent years in studies of proteins containing both ordered and disordered domains and in the characterization of problematic sequences containing repeated tracts of a single or a few amino acids. These sequences are relevant to disease states such as Alzheimer's, Parkinson's, and Huntington's diseases, where disordered proteins misfold into harmful amyloid. Innovative applications of NMR are providing novel insights into mechanisms of protein aggregation and the complexity of IDP interactions with their targets. As a basis for understanding the solution structural ensembles, dynamic behavior, and functional mechanisms of IDPs and IDRs, NMR continues to prove invaluable.
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Affiliation(s)
- H Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, 92037, California, USA
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, 92037, California, USA.
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11
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Virtanen SI, Kiirikki AM, Mikula KM, Iwaï H, Ollila OHS. Heterogeneous dynamics in partially disordered proteins. Phys Chem Chem Phys 2021; 22:21185-21196. [PMID: 32929427 DOI: 10.1039/d0cp03473h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Importance of disordered protein regions is increasingly recognized in biology, but their characterization remains challenging due to the lack of suitable experimental and theoretical methods. NMR experiments can detect multiple timescale dynamics and structural details of disordered protein regions, but their detailed interpretation is often difficult. Here we combine protein backbone 15N spin relaxation data with molecular dynamics (MD) simulations to detect not only heterogeneous dynamics of large partially disordered proteins but also their conformational ensembles. We observed that the rotational dynamics of folded regions in partially disordered proteins is dominated by similar rigid body rotation as in globular proteins, thereby being largely independent of flexible disordered linkers. Disordered regions, on the other hand, exhibit complex rotational motions with multiple timescales below ∼30 ns which are difficult to detect from experimental data alone, but can be captured by MD simulations. Combining MD simulations and backbone 15N spin relaxation data, measured applying segmental isotopic labeling with salt-inducible split intein, we resolved the conformational ensemble and dynamics of partially disordered periplasmic domain of TonB protein from Helicobacter pylori containing 250 residues. To demonstrate the universality of our approach, it was applied also to the partially disordered region of chicken Engrailed 2. Our results pave the way in understanding how TonB transfers energy from inner membrane to the outer membrane receptors in Gram-negative bacteria, as well as the function of other proteins with disordered domains.
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Affiliation(s)
- Salla I Virtanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Anne M Kiirikki
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Kornelia M Mikula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - O H Samuli Ollila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
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12
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Oeemig JS, Beyer HM, Aranko AS, Mutanen J, Iwaï H. Substrate specificities of inteins investigated by QuickDrop-cassette mutagenesis. FEBS Lett 2020; 594:3338-3355. [PMID: 32805768 DOI: 10.1002/1873-3468.13909] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 08/05/2020] [Accepted: 08/10/2020] [Indexed: 01/21/2023]
Abstract
Inteins catalyze self-excision from host precursor proteins while concomitantly ligating the flanking substrates (exteins) with a peptide bond. Noncatalytic extein residues near the splice junctions, such as the residues at the -1 and +2 positions, often strongly influence the protein-splicing efficiency. The substrate specificities of inteins have not been studied for many inteins. We developed a convenient mutagenesis platform termed "QuickDrop"-cassette mutagenesis for investigating the influences of 20 amino acid types at the -1 and +2 positions of different inteins. We elucidated 17 different profiles of the 20 amino acid dependencies across different inteins. The substrate specificities will accelerate our understanding of the structure-function relationship at the splicing junctions for broader applications of inteins in biotechnology and molecular biosciences.
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Affiliation(s)
- Jesper S Oeemig
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hannes M Beyer
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - A Sesilja Aranko
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Justus Mutanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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