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Guan D, Chen Z. Affinity Purification of Proteins in Tag-Free Form: Split Intein-Mediated Ultrarapid Purification (SIRP). Methods Mol Biol 2017; 1495:1-12. [PMID: 27714606 DOI: 10.1007/978-1-4939-6451-2_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Proteins purified using affinity-based chromatography often exploit a recombinant affinity tag. Existing methods for the removal of the extraneous tag, needed for many applications, suffer from poor efficiency and/or high cost. Here we describe a simple, efficient, and potentially low-cost approach-split intein-mediated ultrarapid purification (SIRP)-for both the purification of the desired tagged protein from Escherichia coli lysate and removal of the tag in less than 1 h. The N- and C-fragment of a self-cleaving variant of a naturally split DnaE intein from Nostoc punctiforme are genetically fused to the N-terminus of an affinity tag and a protein of interest (POI), respectively. The N-intein/affinity tag is used to functionalize an affinity resin. The high affinity between the N- and C-fragment of DnaE intein enables the POI to be purified from the lysate via affinity to the resin, and the intein-mediated C-terminal cleavage reaction causes tagless POI to be released into the flow-through. The intein cleavage reaction is strongly inhibited by divalent ions (e.g., Zn2+) under non-reducing conditions and is significantly enhanced by reducing conditions. The POI is cleaved efficiently regardless of the identity of the N-terminal amino acid except in the cases of threonine and proline, and the N-intein-functionalized affinity resin can be regenerated for multiple cycles of use.
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Affiliation(s)
- Dongli Guan
- Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA
| | - Zhilei Chen
- Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843, USA.
- Department of Microbial and Molecular Pathogenesis, Texas A&M University Health Science Center, College Station, TX, 77843, USA.
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2
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Postsynthetic Domain Assembly with NpuDnaE and SspDnaB Split Inteins. Appl Biochem Biotechnol 2015; 177:1137-51. [DOI: 10.1007/s12010-015-1802-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/04/2015] [Indexed: 10/23/2022]
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3
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Abstract
Protein splicing in trans by split inteins has increasingly become a powerful protein-engineering tool for protein ligation, both in vivo and in vitro. Over 100 naturally occurring and artificially engineered split inteins have been reported for protein ligation using protein trans-splicing. Here, we review the current status of the reported split inteins in order to delineate an empirical or rational strategy for constructing new split inteins suitable for various applications in biotechnology and chemical biology.
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Affiliation(s)
- A Sesilja Aranko
- Research Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland
| | - Alexander Wlodawer
- Macromolecular Crystallography Laboratory, National Cancer Institute-Frederick, MD 21702, USA
| | - Hideo Iwaï
- Research Program in Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, P.O. Box 65, Helsinki FIN-00014, Finland
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4
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Sorci M, Dassa B, Liu H, Anand G, Dutta AK, Pietrokovski S, Belfort M, Belfort G. Oriented covalent immobilization of antibodies for measurement of intermolecular binding forces between zipper-like contact surfaces of split inteins. Anal Chem 2013; 85:6080-8. [PMID: 23679912 PMCID: PMC3760192 DOI: 10.1021/ac400949t] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In order to measure the intermolecular binding forces between two halves (or partners) of naturally split protein splicing elements called inteins, a novel thiol-hydrazide linker was designed and used to orient immobilized antibodies specific for each partner. Activation of the surfaces was achieved in one step, allowing direct intermolecular force measurement of the binding of the two partners of the split intein (called protein trans-splicing). Through this binding process, a whole functional intein is formed resulting in subsequent splicing. Atomic force microscopy (AFM) was used to directly measure the split intein partner binding at 1 μm/s between native (wild-type) and mixed pairs of C- and N-terminal partners of naturally occurring split inteins from three cyanobacteria. Native and mixed pairs exhibit similar binding forces within the error of the measurement technique (~52 pN). Bioinformatic sequence analysis and computational structural analysis discovered a zipper-like contact between the two partners with electrostatic and nonpolar attraction between multiple aligned ion pairs and hydrophobic residues. Also, we tested the Jarzynski's equality and demonstrated, as expected, that nonequilibrium dissipative measurements obtained here gave larger energies of interaction as compared with those for equilibrium. Hence, AFM coupled with our immobilization strategy and computational studies provides a useful analytical tool for the direct measurement of intermolecular association of split inteins and could be extended to any interacting protein pair.
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Affiliation(s)
- Mirco Sorci
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Bareket Dassa
- Molecular Genetics Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Hongwei Liu
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Gaurav Anand
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Amit K. Dutta
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Shmuel Pietrokovski
- Molecular Genetics Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Marlene Belfort
- Department of Biological Sciences, University at Albany, SUNY, Albany, NY 12222
| | - Georges Belfort
- Howard P. Isermann Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies Rensselaer Polytechnic Institute, Troy, NY 12180
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5
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Guan D, Ramirez M, Chen Z. Split intein mediated ultra‐rapid purification of tagless protein (SIRP). Biotechnol Bioeng 2013; 110:2471-81. [DOI: 10.1002/bit.24913] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 02/15/2013] [Accepted: 03/22/2013] [Indexed: 11/11/2022]
Affiliation(s)
- Dongli Guan
- Department of Chemical Engineering, 3122 TAMU, Artie McFerrinTexas A&M UniversityCollege StationTX 77843
| | - Miguel Ramirez
- Department of Chemical Engineering, 3122 TAMU, Artie McFerrinTexas A&M UniversityCollege StationTX 77843
| | - Zhilei Chen
- Department of Chemical Engineering, 3122 TAMU, Artie McFerrinTexas A&M UniversityCollege StationTX 77843
- Department of Microbial and Molecular PathogenesisTexas A&M Health Science CenterCollege StationTX
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6
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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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Ramirez M, Valdes N, Guan D, Chen Z. Engineering split intein DnaE from Nostoc punctiforme for rapid protein purification. Protein Eng Des Sel 2012; 26:215-23. [PMID: 23223807 DOI: 10.1093/protein/gzs097] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the engineering of a DnaE intein able to catalyze rapid C-terminal cleavage in the absence of N-terminal cleavage. A single mutation in DnaE intein from Nostoc punctiforme PCC73102 (NpuDnaE), Asp118Gly, was introduced based on sequence alignment with a previously engineered C-terminal cleaving intein mini-MtuRecA. This mutation was able to both suppress N-terminal cleavage and significantly elevate C-terminal cleavage efficiency. Molecular modeling suggests that in NpuDnaE Asp118 forms a hydrogen bond with the penultimate Asn, preventing its spontaneous cyclization prior to N-terminal cleavage. Mutation of Asp118 to Gly essentially abolishes this restriction leading to subsequent C-terminal cleavage in the absence of N-terminal cleavage. The Gly118 NpuDnaE mutant exhibits rapid thio-dependent C-terminal cleavage kinetics with 80% completion within 3 h at room temperature. We used this newly engineered intein to develop both column-free and chromatography-based protein purification methods utilizing the elastin-like-polypeptide and chitin-binding protein as removable purification tags, respectively. We demonstrate rapid target protein purification to electrophoretic purity at yields up to 84 mg per liter of Escherichia coli culture.
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Affiliation(s)
- Miguel Ramirez
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, USA
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Garbe D, Thiel IV, Mootz HD. Protein trans-splicing on an M13 bacteriophage: towards directed evolution of a semisynthetic split intein by phage display. J Pept Sci 2010; 16:575-81. [DOI: 10.1002/psc.1243] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Volkmann G, Sun W, Liu XQ. Controllable protein cleavages through intein fragment complementation. Protein Sci 2010; 18:2393-402. [PMID: 19768808 DOI: 10.1002/pro.249] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intein-based protein cleavages, if carried out in a controllable way, can be useful tools of recombinant protein purification, ligation, and cyclization. However, existing methods using contiguous inteins were often complicated by spontaneous cleavages, which could severely reduce the yield of the desired protein product. Here we demonstrate a new method of controllable cleavages without any spontaneous cleavage, using an artificial S1 split-intein consisting of an 11-aa N-intein (I(N)) and a 144-aa C-intein (I(C)). In a C-cleavage design, the I(C) sequence was embedded in a recombinant precursor protein, and the small I(N) was used as a synthetic peptide to trigger a cleavage at the C-terminus of I(C). In an N-cleavage design, the short I(N) sequence was embedded in a recombinant precursor protein, and the separately produced I(C) protein was used to catalyze a cleavage at the N-terminus of I(N). These N- and C-cleavages showed >95% efficiency, and both successfully avoided any spontaneous cleavage during expression and purification of the precursor proteins. The N-cleavage design also revealed an unexpected and interesting structural flexibility of the I(C) protein. These findings significantly expand the effectiveness of intein-based protein cleavages, and they also reveal important insights of intein structural flexibility and fragment complementation.
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Affiliation(s)
- Gerrit Volkmann
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
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Affiliation(s)
- Henning D Mootz
- Technische Universität Dortmund, Fakultät Chemie, Chemische Biologie, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany.
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Zettler J, Schütz V, Mootz HD. The naturally split Npu DnaE intein exhibits an extraordinarily high rate in the protein trans-splicing reaction. FEBS Lett 2009; 583:909-14. [PMID: 19302791 DOI: 10.1016/j.febslet.2009.02.003] [Citation(s) in RCA: 200] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Revised: 02/02/2009] [Accepted: 02/03/2009] [Indexed: 10/21/2022]
Abstract
We have studied the naturally split alpha subunit of the DNA polymerase III (DnaE) intein from Nostoc punctiforme PCC73102 (Npu) using purified proteins and determined an apparent first-order rate constant of (1.1+/-0.2)x10(-2) s(-1) at 37 degrees C. This represents the highest rate reported for the protein trans-splicing reaction so far (t(1/2) of approximately 60s). Furthermore, the reaction was very robust and high-yielding with respect to different extein sequences, temperatures from 6 to 37 degrees C, and the presence of up to 6 M urea. Given these outstanding properties, the Npu DnaE intein appears to be the intein of choice for many applications in protein and cellular chemistry.
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Affiliation(s)
- Joachim Zettler
- Technische Universität Dortmund, Fakultät Chemie-Chemische Biologie, Dortmund, Germany
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12
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Ludwig C, Schwarzer D, Zettler J, Garbe D, Janning P, Czeslik C, Mootz HD. Semisynthesis of proteins using split inteins. Methods Enzymol 2009; 462:77-96. [PMID: 19632470 DOI: 10.1016/s0076-6879(09)62004-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Protein splicing is an autocatalytic reaction in which an internal protein domain, the intein, excises itself out of a precursor protein and concomitantly links the two flanking sequences, the exteins, with a native peptide bond. In split inteins, the intein domain is divided into two parts that undergo fragment association followed by protein splicing in trans. Thus, the extein sequences joined in the process originate from two separate molecules. The specificity and sequence promiscuity of split inteins make this approach a generally useful tool for the preparation of semisynthetic proteins. To this end, the recombinant part of the protein of interest is expressed as a fusion protein with one split intein fragment. The synthetic part is extended by the other, complementary fragment of the split intein. A recently introduced split intein, in which the N-terminal fragment consists of only 11 native amino acids, has greatly facilitated preparation of the synthetic part by solid-phase peptide synthesis. This intein enables the chemoenzymatic synthesis of N-terminally modified semisynthetic proteins. The reaction can be performed under native conditions and at protein and peptide concentrations in the low micromolar range. In contrast to chemical ligation procedures like native chemical ligation and expressed protein ligation, the incorporation of a thioester group and an aminoterminal cysteine into the two polypeptides to be linked is not necessary. We discuss properties of useful inteins, design rules for split inteins and intein insertion sites and we describe selected examples in detail.
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Affiliation(s)
- Christina Ludwig
- Fakultät Chemie - Chemische Biologie, Technische Universität Dortmund, Dortmund, Germany
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13
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Ludwig C, Pfeiff M, Linne U, Mootz HD. Ligation of a synthetic peptide to the N terminus of a recombinant protein using semisynthetic protein trans-splicing. Angew Chem Int Ed Engl 2007; 45:5218-21. [PMID: 16823791 DOI: 10.1002/anie.200600570] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Christina Ludwig
- Philipps-Universität Marburg, Fachbereich Chemie/Biochemie, Hans-Meerwein-Strasse, 35032 Marburg, Germany
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14
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Ludwig C, Pfeiff M, Linne U, Mootz HD. Ligation eines synthetischen Peptids an den N-Terminus eines rekombinanten Proteins durch semisynthetischestrans-Proteinspleißen. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600570] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Abstract
The introduction of noncanonical amino acids and biophysical probes into peptides and proteins, and total or segmental isotopic labelling has the potential to greatly aid the determination of protein structure, function and protein-protein interactions. To obtain a peptide as large as possible by solid-phase peptide synthesis, native chemical ligation was introduced to enable synthesis of proteins of up to 120 amino acids in length. After the discovery of inteins, with their self-splicing properties and their application in protein synthesis, the semisynthetic methodology, expressed protein ligation, was developed to circumvent size limitation problems. Today, diverse expression vectors are available that allow the production of N- and C-terminal fragments that are needed for ligation to produce large amounts and high purity protein(s) (protein alpha-thioesters and peptides or proteins with N-terminal Cys). Unfortunately, expressed protein ligation is still limited mainly by the requirement of a Cys residue. Of course, additional Cys residues can be introduced into the sequence by site directed mutagenesis or synthesis, however, those mutations may disturb protein structure and function. Recently, alternative ligation approaches have been developed that do not require Cys residues. Accordingly, it is theoretically possible to obtain each modified protein using ligation strategies.
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Affiliation(s)
- Ralf David
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Germany
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16
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Paulmurugan R, Umezawa Y, Gambhir SS. Noninvasive imaging of protein-protein interactions in living subjects by using reporter protein complementation and reconstitution strategies. Proc Natl Acad Sci U S A 2002; 99:15608-13. [PMID: 12438689 PMCID: PMC137764 DOI: 10.1073/pnas.242594299] [Citation(s) in RCA: 254] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study we have developed bioluminescence-imaging strategies to noninvasively and quantitatively image protein-protein interactions in living mice by using a cooled charge-coupled device camera and split reporter technology. We validate both complementation and intein-mediated reconstitution of split firefly luciferase proteins driven by the interaction of two strongly interacting proteins, MyoD and Id. We use transient transfection of cells and image MyoD-Id interaction after induction of gene expression in cell culture and in cells implanted into living mice. Techniques to study protein-protein interactions in living subjects will allow the study of cellular networks, including signal transduction pathways, as well as development and optimization of pharmaceuticals for modulating protein-protein interactions.
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Affiliation(s)
- R Paulmurugan
- Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California Los Angeles-Jonsson Comprehensive Cancer Center, 90095-1770, USA
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17
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Siebold C, Erni B. Intein-mediated cyclization of a soluble and a membrane protein in vivo: function and stability. Biophys Chem 2002; 96:163-71. [PMID: 12034438 DOI: 10.1016/s0301-4622(02)00012-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cyclized subunits of the E. coli glucose transporter were produced in vivo by intein mediated trans-splicing. IIA(Glc) is a beta-sandwich protein, IICB(Glc) spans the membrane eight times. Genes encoding the circularly permuted precursors U(Cdelta)-IIA(Glc)-U(Ndelta) and U(Cdelta)-IICB(Glc)-U(Ndelta) were assembled from DNA fragments encoding the 3' and 5' segments of the recA intein of M. tuberculosis and crr and ptsG of E. coli, respectively. A 20-residues long, Ala-Pro rich linker peptide and/or a histidine tag were used to join the native N- and C-termini in the cyclized proteins. The cyclized proteins complemented growth of glucose auxotrophic strains. Purified, cyclized IIA(Glc) and IICB(Glc) had 100 and 25%, respectively, of wild-type glucose phosphotransferase activity. They had an increased electrophoretic mobility, which decreased upon linearization of the proteins with chymotrypsin. Cyclized IIA(Glc) displayed increased stability against temperature and GuHCl-induced unfolding (75 vs. 70 degrees C; 1.52 vs. 1.05 M).
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Affiliation(s)
- Christian Siebold
- Departement für Chemie und Biochemie, Universität Bern, Bern, Switzerland
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18
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Affiliation(s)
- I Giriat
- Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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Siebold C, Flükiger K, Beutler R, Erni B. Carbohydrate transporters of the bacterial phosphoenolpyruvate: sugar phosphotransferase system (PTS). FEBS Lett 2001; 504:104-11. [PMID: 11532441 DOI: 10.1016/s0014-5793(01)02705-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The glucose transporter of Escherichia coli couples translocation with phosphorylation of glucose. The IICB(Glc) subunit spans the membrane eight times. Split, circularly permuted and cyclized forms of IICB(Glc) are described. The split variant was 30 times more active when the two proteins were encoded by a dicistronic mRNA than by two genes. The stability and activity of circularly permuted forms was improved when they were expressed as fusion proteins with alkaline phosphatase. Cyclized IICB(Glc) and IIA(Glc) were produced in vivo by RecA intein-mediated trans-splicing. Purified, cyclized IIA(Glc) and IICB(Glc) had 100% and 30% of wild-type glucose phosphotransferase activity, respectively. Cyclized IIA(Glc) displayed increased stability against temperature and GuHCl-induced unfolding.
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Affiliation(s)
- C Siebold
- Departement für Chemie und Biochemie, Universität Bern, CH-3012, Bern, Switzerland
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Abstract
Protein splicing is a posttranslational processing event that releases an internal protein sequence from a protein precursor. During the splicing process the internal protein sequence, termed an intein, embedded in the protein precursor self-catalyzes its excision and the ligation of the flanking protein regions, termed exteins. The dissection of the splicing pathway, which involves the precise cleavage and formation of peptide bonds, and the identification of key catalytic residues at the splice junctions have led to the modulation of the protein splicing process as a protein engineering tool. Novel strategies have been developed to use intein-catalyzed reactions for the production and manipulation of proteins and peptides. These new approaches have broken down the size limitation barrier of chemical synthetic methods and are less technically demanding. The purpose of this article is to describe how to use self-splicing inteins in protein semisynthesis and backbone cyclization. The first two sections of the article provide a brief review of the distinct chemical steps that underlie protein splicing and intein enabled technology.
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Affiliation(s)
- M Q Xu
- New England Biolabs, Inc., 32 Tozer Road, Beverly, Massachusetts 01915, USA
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21
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Abstract
Protein splicing is a form of posttranslational processing that consists of the excision of an intervening polypeptide sequence, the intein, from a protein, accompanied by the concomitant joining of the flanking polypeptide sequences, the exteins, by a peptide bond. It requires neither cofactors nor auxiliary enzymes and involves a series of four intramolecular reactions, the first three of which occur at a single catalytic center of the intein. Protein splicing can be modulated by mutation and converted to highly specific self-cleavage and protein ligation reactions that are useful protein engineering tools. Some of the reactions characteristic of protein splicing also occur in other forms of protein autoprocessing, ranging from peptide bond cleavage to conjugation with nonprotein moieties. These mechanistic similarities may be the result of convergent evolution, but in at least one case-hedgehog protein autoprocessing-there is definitely a close evolutionary relationship to protein splicing.
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Affiliation(s)
- H Paulus
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, Massachusetts 02472, USA.
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