1
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Hoffmann S, Terhorst TME, Singh RK, Kümmel D, Pietrokovski S, Mootz HD. Biochemical and Structural Characterization of an Unusual and Naturally Split Class 3 Intein. Chembiochem 2020; 22:364-373. [PMID: 32813312 PMCID: PMC7891396 DOI: 10.1002/cbic.202000509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/19/2020] [Indexed: 12/31/2022]
Abstract
Split inteins are indispensable tools for protein engineering because their ligation and cleavage reactions enable unique modifications of the polypeptide backbone. Three different classes of inteins have been identified according to the nature of the covalent intermediates resulting from the acyl rearrangements in the multistep protein‐splicing pathway. Class 3 inteins employ a characteristic internal cysteine for a branched thioester intermediate. A bioinformatic database search of non‐redundant protein sequences revealed the absence of split variants in 1701 class 3 inteins. We have discovered the first reported split class 3 intein in a metagenomics data set and report its biochemical, mechanistic and structural analysis. The AceL NrdHF intein exhibits low sequence conservation with other inteins and marked deviations in residues at conserved key positions, including a variation of the typical class‐3 WCT triplet motif. Nevertheless, functional analysis confirmed the class 3 mechanism of the intein and revealed excellent splicing yields within a few minutes over a wide range of conditions and with barely detectable cleavage side reactions. A high‐resolution crystal structure of the AceL NrdHF precursor and a mutagenesis study explained the importance and roles of several residues at the key positions. Tolerated substitutions in the flanking extein residues and a high affinity between the split intein fragments further underline the intein's future potential as a ligation tool.
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Affiliation(s)
- Simon Hoffmann
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Tobias M E Terhorst
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Rohit K Singh
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Daniel Kümmel
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
| | - Shmuel Pietrokovski
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Henning D Mootz
- Institute of Biochemistry, University of Muenster, Corrensstraße 36, 48149, Münster, Germany
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2
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Pearson CS, Nemati R, Liu B, Zhang J, Scalabrin M, Li Z, Li H, Fabris D, Belfort M, Belfort G. Structure of an engineered intein reveals thiazoline ring and provides mechanistic insight. Biotechnol Bioeng 2018; 116:709-721. [PMID: 30450538 DOI: 10.1002/bit.26875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/18/2018] [Accepted: 10/26/2018] [Indexed: 11/08/2022]
Abstract
We have engineered an intein which spontaneously and reversibly forms a thiazoline ring at the native N-terminal Lys-Cys splice junction. We identified conditions to stablize the thiazoline ring and provided the first crystallographic evidence, at 1.54 Å resolution, for its existence at an intein active site. The finding bolsters evidence for a tetrahedral oxythiazolidine splicing intermediate. In addition, the pivotal mutation maps to a highly conserved B-block threonine, which is now seen to play a causative role not only in ground-state destabilization of the scissile N-terminal peptide bond, but also in steering the tetrahedral intermediate toward thioester formation, giving new insight into the splicing mechanism. We demonstrated the stability of the thiazoline ring at neutral pH as well as sensitivity to hydrolytic ring opening under acidic conditions. A pH cycling strategy to control N-terminal cleavage is proposed, which may be of interest for biotechnological applications requiring a splicing activity switch, such as for protein recovery in bioprocessing.
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Affiliation(s)
- C Seth Pearson
- Howard P Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
| | - Reza Nemati
- Department of Chemistry, State University of New York, Albany, New York
| | - Binbin Liu
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Jing Zhang
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Matteo Scalabrin
- Department of Chemistry, State University of New York, Albany, New York
| | - Zhong Li
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York
| | - Hongmin Li
- Laboratory of Computational & Structural Biology, Wadsworth Center, New York State Department of Health, Albany, New York.,Department of Biomedical Sciences, School of Public Health, Albany, State University of New York, Albany, New York
| | - Dan Fabris
- Department of Chemistry, State University of New York, Albany, New York
| | - Marlene Belfort
- Department of Biomedical Sciences, School of Public Health, Albany, State University of New York, Albany, New York.,Department of Biological Sciences, Albany, State University of New York, Albany, New York
| | - Georges Belfort
- Howard P Isermann Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York
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3
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Friedel K, Popp MA, Matern JCJ, Gazdag EM, Thiel IV, Volkmann G, Blankenfeldt W, Mootz HD. A functional interplay between intein and extein sequences in protein splicing compensates for the essential block B histidine. Chem Sci 2018; 10:239-251. [PMID: 30713635 PMCID: PMC6333167 DOI: 10.1039/c8sc01074a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/03/2018] [Indexed: 01/28/2023] Open
Abstract
Steric bulk can compensate for a catalytically critical histidine in an intein's active site and promote the N–S acyl shift.
Inteins remove themselves from a precursor protein by protein splicing. Due to the concomitant structural changes of the host protein, this self-processing reaction has enabled many applications in protein biotechnology and chemical biology. We show that the evolved M86 mutant of the Ssp DnaB intein displays a significantly improved tolerance towards non-native amino acids at the N-terminally flanking (–1) extein position compared to the parent intein, in the form of both an artificially trans-splicing split intein and the cis-splicing mini-intein. Surprisingly, side chains with increased steric bulk compared to the native Gly(–1) residue, including d-amino acids, were found to compensate for the essential block B histidine in His73Ala mutants in the initial N–S acyl shift of the protein splicing pathway. In the case of the M86 intein, large (–1) side chains can even rescue protein splicing activity as a whole. With the comparison of three crystal structures, namely of the M86 intein as well as of its Gly(–1)Phe and Gly(–1)Phe/His73Ala mutants, our data supports a model in which the intein's active site can exert a strain by varying mechanisms on the different angles of the scissile bond at the extein–intein junction to effect a ground-state destabilization. The compensatory mechanism of the block B histidine is the first example for the direct functional role of an extein residue in protein splicing. It sheds new light on the extein–intein interplay and on possible consequences of their co-evolution as well as on the laboratory engineering of improved inteins.
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Affiliation(s)
- Kristina Friedel
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Monika A Popp
- Structure and Function of Proteins , Helmholtz Centre for Infection Research , Inhoffenstraße 7 , 38124 , Braunschweig , Germany
| | - Julian C J Matern
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Emerich M Gazdag
- Structure and Function of Proteins , Helmholtz Centre for Infection Research , Inhoffenstraße 7 , 38124 , Braunschweig , Germany
| | - Ilka V Thiel
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Gerrit Volkmann
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
| | - Wulf Blankenfeldt
- Structure and Function of Proteins , Helmholtz Centre for Infection Research , Inhoffenstraße 7 , 38124 , Braunschweig , Germany.,Institute for Biochemistry, Biotechnology and Bioinformatics , Technische Universität Braunschweig , Spielmannstraße 7 , 38106 Braunschweig , Germany
| | - Henning D Mootz
- Institute of Biochemistry , University of Muenster , Wilhelm-Klemm-Str. 2 , 48149 Münster , Germany .
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4
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Ramsoomair CK, Yakely AE, Urbanski LM, Karanja K, Giaccone ZT, Siegart NM, Wang C, Gomez AV, Reitter JN, Mills KV. Coordination of the third step of protein splicing in two cyanobacterial inteins. FEBS Lett 2017. [PMID: 28649707 DOI: 10.1002/1873-3468.12730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The third step of protein splicing is cyclization of Asn coupled to peptide bond cleavage. In two related cyanobacterial inteins, this step is facilitated by Asn or Gln. For a Synechococcus sp. PCC7002 intein, the isolated third step of protein splicing is more efficient with its native Asn than with substitution to Gln. For a Trichodesmium erythraeum intein, its native Gln facilitates the third step as efficiently as with Asn. Despite these differences, the yield of splicing is not affected, suggesting that the third step is influenced by mechanism-linked conformational changes. A conserved catalytic His and the penultimate residue also play roles in promoting side-chain cyclization.
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Affiliation(s)
| | - Anthony E Yakely
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
| | - Laura M Urbanski
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
| | - Kevin Karanja
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
| | | | - Nicolle M Siegart
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
| | - Chunyu Wang
- Department of Chemistry and Chemical Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Department of Biological Sciences, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alvin V Gomez
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
| | - Julie N Reitter
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
| | - Kenneth V Mills
- Department of Chemistry, College of the Holy Cross, Worcester, MA, USA
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5
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NMDA receptors are selectively partitioned into complexes and supercomplexes during synapse maturation. Nat Commun 2016; 7:11264. [PMID: 27117477 PMCID: PMC5227094 DOI: 10.1038/ncomms11264] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/04/2016] [Indexed: 01/29/2023] Open
Abstract
How neuronal proteomes self-organize is poorly understood because of their inherent molecular and cellular complexity. Here, focusing on mammalian synapses we use blue-native PAGE and ‘gene-tagging' of GluN1 to report the first biochemical purification of endogenous NMDA receptors (NMDARs) directly from adult mouse brain. We show that NMDARs partition between two discrete populations of receptor complexes and ∼1.5 MDa supercomplexes. We tested the assembly mechanism with six mouse mutants, which indicates a tripartite requirement of GluN2B, PSD93 and PSD95 gate the incorporation of receptors into ∼1.5 MDa supercomplexes, independent of either canonical PDZ-ligands or GluN2A. Supporting the essential role of GluN2B, quantitative gene-tagging revealed a fourfold molar excess of GluN2B over GluN2A in adult forebrain. NMDAR supercomplexes are assembled late in postnatal development and triggered by synapse maturation involving epigenetic and activity-dependent mechanisms. Finally, screening the quaternary organization of 60 native proteins identified numerous discrete supercomplexes that populate the mammalian synapse. NMDARs and MAGUK proteins are capable of forming higher-order protein assemblies, however their organisation in the intact brain is unclear. Here, Frank et al. identify mouse and human supercomplexes and discover their mechanism of assembly using genetic tagging and affinity purification.
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6
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Ulasan M, Yavuz E, Bagriacik EU, Cengeloglu Y, Yavuz MS. Biocompatible thermoresponsive PEGMA nanoparticles crosslinked with cleavable disulfide-based crosslinker for dual drug release. J Biomed Mater Res A 2014; 103:243-51. [DOI: 10.1002/jbm.a.35146] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/25/2014] [Accepted: 02/18/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Mehmet Ulasan
- Department of Chemistry; Selcuk University; Konya Turkey
- Advanced Technology Research and Application Center, Selcuk University; Konya Turkey
| | - Emine Yavuz
- Advanced Technology Research and Application Center, Selcuk University; Konya Turkey
- Department of Immunology; Gazi University; Ankara Turkey
| | | | | | - Mustafa Selman Yavuz
- Advanced Technology Research and Application Center, Selcuk University; Konya Turkey
- Metallurgy and Materials Engineering; Selcuk University; Konya Turkey
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7
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Abstract
Inteins are nature's escape artists; they facilitate their excision from flanking polypeptides (exteins) concomitant with extein ligation to produce a mature host protein. Splicing requires sequential nucleophilic displacement reactions catalyzed by strategies similar to proteases and asparagine lyases. Inteins require precise reaction coordination rather than rapid turnover or tight substrate binding because they are single turnover enzymes with covalently linked substrates. This has allowed inteins to explore alternative mechanisms with different steps or to use different methods for activation and coordination of the steps. Pressing issues include understanding the underlying details of catalysis and how the splicing steps are controlled.
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Affiliation(s)
- Kenneth V Mills
- From the Department of Chemistry, College of the Holy Cross, Worcester, Massachusetts 01610
| | - Margaret A Johnson
- the Department of Chemistry, University of Alabama at Birmingham, Birmingham, Alabama 35294, and
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8
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Volkmann G, Mootz HD. Recent progress in intein research: from mechanism to directed evolution and applications. Cell Mol Life Sci 2013; 70:1185-206. [PMID: 22926412 PMCID: PMC11113529 DOI: 10.1007/s00018-012-1120-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 07/23/2012] [Accepted: 08/06/2012] [Indexed: 10/27/2022]
Abstract
Inteins catalyze a post-translational modification known as protein splicing, where the intein removes itself from a precursor protein and concomitantly ligates the flanking protein sequences with a peptide bond. Over the past two decades, inteins have risen from a peculiarity to a rich source of applications in biotechnology, biomedicine, and protein chemistry. In this review, we focus on developments of intein-related research spanning the last 5 years, including the three different splicing mechanisms and their molecular underpinnings, the directed evolution of inteins towards improved splicing in exogenous protein contexts, as well as novel applications of inteins for cell biology and protein engineering, which were made possible by a clearer understanding of the protein splicing mechanism.
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Affiliation(s)
- Gerrit Volkmann
- Institute of Biochemistry, University of Münster, Wilhelm-Klemm-Str. 2, 48149 Münster, Germany
| | - Henning D. Mootz
- Institute of Biochemistry, University of Münster, Wilhelm-Klemm-Str. 2, 48149 Münster, Germany
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