Summary: The internal fragments of precursor proteins (INternal proTEINS) that are autocatalytically removed by PROTEIN SPLICING. The flanking fragments (EXTEINS) are ligated forming mature proteins. The nucleic acid sequences coding for inteins are considered to be MOBILE GENETIC ELEMENTS. Inteins are composed of self-splicing domains and an endonuclease domain which plays a role in the spread of the intein's genomic sequence. Mini-inteins are composed of the self-splicing domains only.

Top Publications

  1. Züger S, Iwai H. Intein-based biosynthetic incorporation of unlabeled protein tags into isotopically labeled proteins for NMR studies. Nat Biotechnol. 2005;23:736-40 pubmed
    ..Using this in vivo approach, unlabeled protein tags can be incorporated into isotopically labeled target proteins to improve protein stability and solubility for study by solution NMR spectroscopy. ..
  2. Mills K, Perler F. The mechanism of intein-mediated protein splicing: variations on a theme. Protein Pept Lett. 2005;12:751-5 pubmed
    ..Non-canonical inteins missing conserved nucleophilic residues at the N- or C-terminus likely splice using variations of the standard ..
  3. McGinty R, Chatterjee C, Muir T. Semisynthesis of ubiquitylated proteins. Methods Enzymol. 2009;462:225-43 pubmed publisher
    ..The utility of this methodology is illustrated through the synthesis of ubiquitylated histones. ..
  4. Culley A, Asuncion B, Steward G. Detection of inteins among diverse DNA polymerase genes of uncultivated members of the Phycodnaviridae. ISME J. 2009;3:409-18 pubmed publisher
    ..Of the 20 new sequence types reported here, three were serendipitously found to contain protein introns, or inteins. Sequence analysis of the inteins suggested that all three have self-splicing domains and are apparently capable ..
  5. Dassa B, Yanai I, Pietrokovski S. New type of polyubiquitin-like genes with intein-like autoprocessing domains. Trends Genet. 2004;20:538-42 pubmed
    ..These contain tandem repeats of ubiquitin-like domains interspersed with autocatalytic intein-like domains. Inteins and related protein domains post-translationally process their own precursor proteins by protein-splicing, ..
  6. Borra R, Dong D, Elnagar A, Woldemariam G, Camarero J. In-cell fluorescence activation and labeling of proteins mediated by FRET-quenched split inteins. J Am Chem Soc. 2012;134:6344-53 pubmed publisher
    ..We report in this work the use of fluorescence resonance emission transfer (FRET)-quenched DnaE split inteins for the site-specific labeling and concomitant fluorescence activation of proteins in living cells...
  7. Möhlmann S, Bringmann P, Greven S, Harrenga A. Site-specific modification of ED-B-targeting antibody using intein-fusion technology. BMC Biotechnol. 2011;11:76 pubmed publisher
    ..The described protocols can be used to prepare immunoconjugates of high homogeneity and with a defined drug load of two. The attachment to the C-termini is expected to retain the affinity and effector functions of the antibodies. ..
  8. Barzel A, Naor A, Privman E, Kupiec M, Gophna U. Homing endonucleases residing within inteins: evolutionary puzzles awaiting genetic solutions. Biochem Soc Trans. 2011;39:169-73 pubmed publisher
    b>Inteins are selfish genetic elements that disrupt the sequence of protein-coding genes and are excised post-translationally...
  9. Reitter J, Mills K. Canonical protein splicing of a class 1 intein that has a class 3 noncanonical sequence motif. J Bacteriol. 2011;193:994-7 pubmed publisher
    A Thermobifida fusca intein has two characteristics of class 3 inteins: a noncontiguous covariant Trp-Cys-Thr triplet and a Ser flanking its C terminus. However, it has Cys at position one, characteristic of class 1 inteins...

More Information


  1. Vila Perello M, Muir T. Biological applications of protein splicing. Cell. 2010;143:191-200 pubmed publisher
    ..Collectively, these technologies help bridge the fields of chemistry and biology, allowing hitherto impossible manipulations of protein covalent structure. These tools and their application are the subject of this Primer. ..
  2. Volkmann G, Iwai H. Protein trans-splicing and its use in structural biology: opportunities and limitations. Mol Biosyst. 2010;6:2110-21 pubmed publisher
    ..These types of modifications can be elegantly achieved with the use of split inteins in a site- and/or region-specific manner...
  3. Brace L, Southworth M, Tori K, Cushing M, Perler F. The Deinococcus radiodurans Snf2 intein caught in the act: detection of the Class 3 intein signature Block F branched intermediate. Protein Sci. 2010;19:1525-33 pubmed publisher
    b>Inteins are the protein equivalent of introns. They are remarkable and robust single turnover enzymes that splice out of precursor proteins during post-translational maturation of the host protein (extein)...
  4. Muona M, Aranko A, Raulinaitis V, Iwai H. Segmental isotopic labeling of multi-domain and fusion proteins by protein trans-splicing in vivo and in vitro. Nat Protoc. 2010;5:574-87 pubmed publisher
    ..The total preparation time of a segmentally labeled sample can be as short as 7-13 d depending on the protocol used. ..
  5. Reulen S, van Baal I, Raats J, Merkx M. Efficient, chemoselective synthesis of immunomicelles using single-domain antibodies with a C-terminal thioester. BMC Biotechnol. 2009;9:66 pubmed publisher
    ..These proteins are promising building blocks for the chemoselective functionalization via NCL of a broad range of nanoparticle scaffolds, including micelles, liposomes and dendrimers. ..
  6. Fong B, Wu W, Wood D. Optimization of ELP-intein mediated protein purification by salt substitution. Protein Expr Purif. 2009;66:198-202 pubmed publisher
    ..These improvements thus significantly increase the attractiveness of this highly general and economical method for recombinant protein purification. ..
  7. Elleuche S, Pelikan C, Nolting N, Pöggeler S. Inteins and introns within the prp8 -gene of four Eupenicillium species. J Basic Microbiol. 2009;49:52-7 pubmed publisher
    b>Inteins are protein-intervening sequences that are translated with the host protein and can self-excise themselves post-translationally in an autocatalytic process...
  8. Williams N, Liepinsh E, Watt S, Prosselkov P, Matthews J, Attard P, et al. Stabilization of native protein fold by intein-mediated covalent cyclization. J Mol Biol. 2005;346:1095-108 pubmed
    ..Global unfolding of the N-terminal domain of E.coli DnaB is thus promoted strongly by spatial separation of the N and C termini, whereas their proximity is much less important for folding. ..
  9. Butler M, Goodwin T, Poulter R. Two new fungal inteins. Yeast. 2005;22:493-501 pubmed
    ..Subsequent studies have found allelic PRP8 inteins in several species of yeast and filamentous ascomycetes...
  10. Raoult D, Audic S, Robert C, Abergel C, Renesto P, Ogata H, et al. The 1.2-megabase genome sequence of Mimivirus. Science. 2004;306:1344-50 pubmed
    ..This new sequence data might help shed a new light on the origin of DNA viruses and their role in the early evolution of eukaryotes. ..
  11. Hiraga K, Derbyshire V, Dansereau J, Van Roey P, Belfort M. Minimization and stabilization of the Mycobacterium tuberculosis recA intein. J Mol Biol. 2005;354:916-26 pubmed
    Many naturally occurring inteins consist of two functionally independent domains, a protein-splicing domain and an endonuclease domain...
  12. Brenzel S, Kurpiers T, Mootz H. Engineering artificially split inteins for applications in protein chemistry: biochemical characterization of the split Ssp DnaB intein and comparison to the split Sce VMA intein. Biochemistry. 2006;45:1571-8 pubmed
    ..Split inteins can be artificially generated by genetic means; however, the purified inteinN and inteinC fragments usually ..
  13. Kunes Y, Gion W, Fung E, Salfeld J, Zhu R, Sakorafas P, et al. Expression of antibodies using single-open reading frame vector design and polyprotein processing from mammalian cells. Biotechnol Prog. 2009;25:735-44 pubmed publisher
    ..Its affinity to antigen, as measured by surface plasmon resonance (SPR), is indistinguishable from that of the same antibody produced using conventional method. ..
  14. Tori K, Perler F. Expanding the definition of class 3 inteins and their proposed phage origin. J Bacteriol. 2011;193:2035-41 pubmed publisher
    b>Inteins are the protein equivalent of introns. Their protein splicing activity is essential for the host protein's maturation and function. Inteins are grouped into three classes based on sequence signature and splicing mechanism...
  15. Georgiou G, Jeong K. Proteins from PHB granules. Protein Sci. 2005;14:1385-6 pubmed
  16. Elleuche S, Pöggeler S. Inteins, valuable genetic elements in molecular biology and biotechnology. Appl Microbiol Biotechnol. 2010;87:479-89 pubmed publisher
    b>Inteins are internal protein elements that self-excise from their host protein and catalyze ligation of the flanking sequences (exteins) with a peptide bond. They are found in organisms in all three domains of life, and in viral proteins...
  17. Appleby Tagoe J, Thiel I, Wang Y, Wang Y, Mootz H, Liu X. Highly efficient and more general cis- and trans-splicing inteins through sequential directed evolution. J Biol Chem. 2011;286:34440-7 pubmed publisher
    b>Inteins are internal protein sequences that post-translationally self-excise and splice together the flanking sequences, the so-called exteins. Natural and engineered inteins have been used in many practical applications...
  18. Tan L, Yao S. Intein-mediated, in vitro and in vivo protein modifications with small molecules. Protein Pept Lett. 2005;12:769-75 pubmed
  19. Lohmueller J, Armel T, Silver P. A tunable zinc finger-based framework for Boolean logic computation in mammalian cells. Nucleic Acids Res. 2012;40:5180-7 pubmed publisher
    ..Together, these components comprise a robust platform for building mammalian synthetic gene circuits capable of precisely modulating cellular behavior. ..
  20. Tori K, Cheriyan M, Pedamallu C, Contreras M, Perler F. The Thermococcus kodakaraensis Tko CDC21-1 intein activates its N-terminal splice junction in the absence of a conserved histidine by a compensatory mechanism. Biochemistry. 2012;51:2496-505 pubmed publisher
    b>Inteins and other self-catalytic enzymes, such as glycosylasparaginases and hedgehog precursors, initiate autocleavage by converting a peptide bond to a (thio)ester bond when Ser, Thr, or Cys undergoes an N-[S/O] acyl migration assisted ..
  21. Zeidler M, Tan C, Bellaiche Y, Cherry S, Häder S, Gayko U, et al. Temperature-sensitive control of protein activity by conditionally splicing inteins. Nat Biotechnol. 2004;22:871-6 pubmed
    ..Here we describe a system to generate temperature-sensitive alleles based on conditionally active inteins. We have identified temperature-sensitive splicing variants of the yeast Saccharomyces cerevisiae vacuolar ATPase ..
  22. Kwon Y, Coleman M, Camarero J. Selective immobilization of proteins onto solid supports through split-intein-mediated protein trans-splicing. Angew Chem Int Ed Engl. 2006;45:1726-9 pubmed
  23. Dassa B, London N, Stoddard B, Schueler Furman O, Pietrokovski S. Fractured genes: a novel genomic arrangement involving new split inteins and a new homing endonuclease family. Nucleic Acids Res. 2009;37:2560-73 pubmed publisher
    b>Inteins are genetic elements, inserted in-frame into protein-coding genes, whose products catalyze their removal from the protein precursor via a protein-splicing reaction...
  24. Sharma S, Chong S, Harcum S. Intein-mediated protein purification of fusion proteins expressed under high-cell density conditions in E. coli. J Biotechnol. 2006;125:48-56 pubmed
    ..The ability of inteins to catalyze a controllable peptide bond cleavage reaction can be used to separate a recombinant protein from its ..
  25. Dori Bachash M, Dassa B, Peleg O, Pineiro S, Jurkevitch E, Pietrokovski S. Bacterial intein-like domains of predatory bacteria: a new domain type characterized in Bdellovibrio bacteriovorus. Funct Integr Genomics. 2009;9:153-66 pubmed publisher
    ..bacteriovorus predator. The modular structure of the protein, its localization, and complex processing suggest that it may be involved in the interaction between the predator and its prey. ..
  26. Oeemig J, Zhou D, Kajander T, Wlodawer A, Iwaï H. NMR and crystal structures of the Pyrococcus horikoshii RadA intein guide a strategy for engineering a highly efficient and promiscuous intein. J Mol Biol. 2012;421:85-99 pubmed publisher
    ..b>Inteins require the involvement for the splicing of the first residue of the extein that follows the intein (which is Cys,..
  27. Xie Y, Luan C, Zhang H, Han F, Feng J, Choi Y, et al. Effects of thioredoxin: SUMO and intein on soluble fusion expression of an antimicrobial peptide OG2 in Escherichia coli. Protein Pept Lett. 2013;20:54-60 pubmed
    ..The OG2 released by both tobacco etch virus protease and enterokinase from Trx-OG2 showed strong antimicrobial activity against Staphylococcus aureus ATCC25923. ..
  28. Johnson M, Southworth M, Herrmann T, Brace L, Perler F, W thrich K. NMR structure of a KlbA intein precursor from Methanococcus jannaschii. Protein Sci. 2007;16:1316-28 pubmed publisher
    Certain proteins of unicellular organisms are translated as precursor polypeptides containing inteins (intervening proteins), which are domains capable of performing protein splicing...
  29. Gillies A, Mahmoud R, Wood D. PHB-intein-mediated protein purification strategy. Methods Mol Biol. 2009;498:173-83 pubmed publisher
    ..This method has been shown to yield 35-40 microg of purified product per milliliter of liquid cell culture and is likely to be applicable to a wide range of expression hosts. ..
  30. Shah N, Dann G, Vila Perello M, Liu Z, Muir T. Ultrafast protein splicing is common among cyanobacterial split inteins: implications for protein engineering. J Am Chem Soc. 2012;134:11338-41 pubmed publisher
    We describe the first systematic study of a family of inteins, the split DnaE inteins from cyanobacteria...
  31. Kurpiers T, Mootz H. Site-specific chemical modification of proteins with a prelabelled cysteine tag using the artificially split Mxe GyrA intein. Chembiochem. 2008;9:2317-25 pubmed publisher
    ..Our approach combines the benefits of the plethora of commercially available cysteine-reactive probes with a straightforward route for their site-specific incorporation even into complex and cysteine-rich proteins. ..
  32. Wong S, Mills E, Truong K. Simultaneous assembly of two target proteins using split inteins for live cell imaging. Protein Eng Des Sel. 2013;26:207-13 pubmed publisher
    b>Inteins are protein elements that covalently reassemble proteins from two precursor fragments in a process known as protein splicing...
  33. Ludwig C, Schwarzer D, Mootz H. Interaction studies and alanine scanning analysis of a semi-synthetic split intein reveal thiazoline ring formation from an intermediate of the protein splicing reaction. J Biol Chem. 2008;283:25264-72 pubmed publisher
  34. Zhao Z, Lu W, Dun B, Jin D, Ping S, Zhang W, et al. Purification of green fluorescent protein using a two-intein system. Appl Microbiol Biotechnol. 2008;77:1175-80 pubmed
    ..The GFPmut3* was sandwiched between two self-cleaving inteins. This approach avoided the loss of the target protein which may result from in vivo cleavage of a single intein ..
  35. Vila Perello M, Liu Z, Shah N, Willis J, Idoyaga J, Muir T. Streamlined expressed protein ligation using split inteins. J Am Chem Soc. 2013;135:286-92 pubmed publisher
    ..and purification of recombinant protein ?-thioesters using engineered versions of naturally split DnaE inteins. This family of autoprocessing enzymes is closely related to the inteins currently used for protein ?-thioester ..
  36. Sorci M, Dassa B, Liu H, Anand G, Dutta A, Pietrokovski S, et al. 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 pubmed publisher
    ..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...
  37. Qi X, Wang J, Meng Q, Liu X. Alternative nucleophilic residues in intein catalysis of protein splicing. Protein Pept Lett. 2011;18:1226-32 pubmed
    Protein-splicing inteins are widespread in nature and have found many applications in protein research and engineering...
  38. Ellilä S, Jurvansuu J, Iwai H. Evaluation and comparison of protein splicing by exogenous inteins with foreign exteins in Escherichia coli. FEBS Lett. 2011;585:3471-7 pubmed publisher
    Protein splicing catalyzed by inteins has enabled various biotechnological applications such as protein ligation. Successful applications of inteins are often limited by splicing efficiency...
  39. Volkmann G, Liu X. Protein C-terminal labeling and biotinylation using synthetic peptide and split-intein. PLoS ONE. 2009;4:e8381 pubmed publisher
    ..The types of chemical labeling may be limited only by the ability of chemical synthesis to produce the small C-intein peptide containing the desired chemical groups. ..
  40. Butler M, Poulter R. The PRP8 inteins in Cryptococcus are a source of phylogenetic and epidemiological information. Fungal Genet Biol. 2005;42:452-63 pubmed
    Only two nuclear encoded inteins have been described. The first, SceVMA, was found in a vacuolar ATPase gene of Saccharomyces cerevisiae and related yeasts. The second, CnePRP8, was found in the PRP8 gene of Cryptococcus neoformans...
  41. Banki M, Gerngross T, Wood D. Novel and economical purification of recombinant proteins: intein-mediated protein purification using in vivo polyhydroxybutyrate (PHB) matrix association. Protein Sci. 2005;14:1387-95 pubmed
    ..second is a recently developed group of self-cleaving affinity tags based on protein splicing elements known as inteins. By combining these technologies with a PHB-specific binding protein, a self-contained protein expression and ..
  42. Zhang L, Xiao N, Pan Y, Zheng Y, Pan Z, Luo Z, et al. Binding and inhibition of copper ions to RecA inteins from Mycobacterium tuberculosis. Chemistry. 2010;16:4297-306 pubmed publisher
    ..Both Cu(+) and Cu(2+) exhibited high binding affinity to inteins, while different binding sites were identified...
  43. Goodwin T, Butler M, Poulter R. Multiple, non-allelic, intein-coding sequences in eukaryotic RNA polymerase genes. BMC Biol. 2006;4:38 pubmed publisher
    b>Inteins are self-splicing protein elements. They are translated as inserts within host proteins that excise themselves and ligate the flanking portions of the host protein (exteins) with a peptide bond...
  44. Du Z, Shemella P, Liu Y, McCallum S, Pereira B, Nayak S, et al. Highly conserved histidine plays a dual catalytic role in protein splicing: a pKa shift mechanism. J Am Chem Soc. 2009;131:11581-9 pubmed publisher
    ..In inteins, several conserved histidines have been shown to play important roles in protein splicing, including the most ..
  45. Tan G, Chen M, Foote C, Tan C. Temperature-sensitive mutations made easy: generating conditional mutations by using temperature-sensitive inteins that function within different temperature ranges. Genetics. 2009;183:13-22 pubmed publisher
    ..The 41 TS inteins function in five different temperature ranges, with permissive temperatures ranging from 18 degrees to 30 degrees ..
  46. Amitai G, Callahan B, Stanger M, Belfort G, Belfort M. Modulation of intein activity by its neighboring extein substrates. Proc Natl Acad Sci U S A. 2009;106:11005-10 pubmed publisher
    b>Inteins comprise a large family of phylogenetically widespread self-splicing protein catalysts that colonize diverse host proteins...
  47. Lockless S, Muir T. Traceless protein splicing utilizing evolved split inteins. Proc Natl Acad Sci U S A. 2009;106:10999-1004 pubmed publisher
    Split inteins are parasitic genetic elements frequently found inserted into reading frames of essential proteins. Their association and excision restore host protein function through a protein self-splicing reaction...
  48. Saleh L, Perler F. Protein splicing in cis and in trans. Chem Rec. 2006;6:183-93 pubmed
    ..Understanding the protein splicing pathway has allowed scientists to harness inteins for numerous applications.
  49. Muona M, Aranko A, Iwai H. Segmental isotopic labelling of a multidomain protein by protein ligation by protein trans-splicing. Chembiochem. 2008;9:2958-61 pubmed publisher
  50. Xia Z, Xing Y, So M, Koh A, Sinclair R, Rao J. Multiplex detection of protease activity with quantum dot nanosensors prepared by intein-mediated specific bioconjugation. Anal Chem. 2008;80:8649-55 pubmed publisher
    ..The suitability of these nanosensors for a multiplex protease assay has also been shown. ..
  51. Gillies A, Hsii J, Oak S, Wood D. Rapid cloning and purification of proteins: gateway vectors for protein purification by self-cleaving tags. Biotechnol Bioeng. 2008;101:229-40 pubmed publisher
    ..This technology could greatly facilitate process optimization, allowing several targets and methods to be tested in a high-throughput manner. ..
  52. Pearl E, Bokor A, Butler M, Poulter R, Wilbanks S. Preceding hydrophobic and beta-branched amino acids attenuate splicing by the CnePRP8 intein. Biochim Biophys Acta. 2007;1774:995-1001 pubmed
    ..Both these assays sensitively report impairment of splicing and provide information on how context constrains the splicing ability of Cne PRP8. ..
  53. Elleuche S, Pöggeler S. Trans-splicing of an artificially split fungal mini-intein. Biochem Biophys Res Commun. 2007;355:830-4 pubmed
    b>Inteins are internal protein domains found inside the coding region of different proteins...