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Inteins, valuable genetic elements in molecular biology and biotechnology.

Elleuche S, Pöggeler S - Appl. Microbiol. Biotechnol. (2010)

Bottom Line: They are found in organisms in all three domains of life, and in viral proteins.Intein excision is a posttranslational process that does not require auxiliary enzymes or cofactors.This review summarizes the catalytic activities and structures of inteins, and focuses on the advantages of some recent intein applications in molecular biology and biotechnology.

View Article: PubMed Central - PubMed

Affiliation: Institute of Technical Microbiology, Technical University Hamburg-Harburg, Kasernenstr. 12, 21073, Hamburg, Germany.

ABSTRACT
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. Intein excision is a posttranslational process that does not require auxiliary enzymes or cofactors. This self-excision process is called protein splicing, by analogy to the splicing of RNA introns from pre-mRNA. Protein splicing involves only four intramolecular reactions, and a small number of key catalytic residues in the intein and exteins. Protein-splicing can also occur in trans. In this case, the intein is separated into N- and C-terminal domains, which are synthesized as separate components, each joined to an extein. The intein domains reassemble and link the joined exteins into a single functional protein. Understanding the cis- and trans-protein splicing mechanisms led to the development of intein-mediated protein-engineering applications, such as protein purification, ligation, cyclization, and selenoprotein production. This review summarizes the catalytic activities and structures of inteins, and focuses on the advantages of some recent intein applications in molecular biology and biotechnology.

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Structure of large and mini-inteins. Conserved elements in a large intein and mini-intein are indicated. The white and grey areas A, N2, B, N4, C, D, E, H, F, and G are conserved intein motifs identified by Pietrokovski (1994, 1998) and Perler et al. (1994). The exteins are illustrated in black and the intein sequence in blue. The site of insertion of the homing endonuclease in large inteins is indicated by the dark vertical line. Conserved amino acid residues of the intein and the C-extein are indicated below
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Fig2: Structure of large and mini-inteins. Conserved elements in a large intein and mini-intein are indicated. The white and grey areas A, N2, B, N4, C, D, E, H, F, and G are conserved intein motifs identified by Pietrokovski (1994, 1998) and Perler et al. (1994). The exteins are illustrated in black and the intein sequence in blue. The site of insertion of the homing endonuclease in large inteins is indicated by the dark vertical line. Conserved amino acid residues of the intein and the C-extein are indicated below

Mentions: Inteins are classified into two groups, large and minimal (mini) (Liu 2000). Large inteins contain a homing endonuclease domain that is absent in mini-inteins. Homing endonucleases are site-specific, double-strand DNA endonucleases that promote the lateral transfer between genomes of their own coding region with flanking sequences, in a recombination-dependent process known as “homing.” Usually, homing endonucleases are encoded by an open reading frame within an intron or intein (Belfort et al. 2005; Chevalier and Stoddard 2001). Large inteins are bi-functional proteins, with a protein splicing domain, and a central endonuclease domain. Splicing-efficient mini-inteins have been engineered from large inteins by deleting the central endonuclease domain, demonstrating that the endonuclease domain is not involved in protein splicing (Chong and Xu 1997; Derbyshire et al. 1997; Shingledecker et al. 1998). The splicing domain is split by the endonuclease domain into N- and C-terminal subdomains, which contain conserved blocks of amino acids, with blocks A, N2, B, and N4 in the N-terminal subdomain, and blocks G and F in the C-terminal subdomain (Perler et al. 1997; Pietrokovski 1994, 1998) These domains can also be identified in mini-inteins (Fig. 2). The three-dimensional structures of naturally occurring mini-inteins and engineered mini-inteins reveal that the N- and C-terminal splicing domains form a common horseshoe-like 12-β-strand scaffold termed the Hedgehog/Intein (HINT) module (Ding et al. 2003; Hall et al. 1997; Klabunde et al. 1998; Koonin 1995; Perler 1998; Sun et al. 2005; Van Roey et al. 2007).Fig. 2


Inteins, valuable genetic elements in molecular biology and biotechnology.

Elleuche S, Pöggeler S - Appl. Microbiol. Biotechnol. (2010)

Structure of large and mini-inteins. Conserved elements in a large intein and mini-intein are indicated. The white and grey areas A, N2, B, N4, C, D, E, H, F, and G are conserved intein motifs identified by Pietrokovski (1994, 1998) and Perler et al. (1994). The exteins are illustrated in black and the intein sequence in blue. The site of insertion of the homing endonuclease in large inteins is indicated by the dark vertical line. Conserved amino acid residues of the intein and the C-extein are indicated below
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2874743&req=5

Fig2: Structure of large and mini-inteins. Conserved elements in a large intein and mini-intein are indicated. The white and grey areas A, N2, B, N4, C, D, E, H, F, and G are conserved intein motifs identified by Pietrokovski (1994, 1998) and Perler et al. (1994). The exteins are illustrated in black and the intein sequence in blue. The site of insertion of the homing endonuclease in large inteins is indicated by the dark vertical line. Conserved amino acid residues of the intein and the C-extein are indicated below
Mentions: Inteins are classified into two groups, large and minimal (mini) (Liu 2000). Large inteins contain a homing endonuclease domain that is absent in mini-inteins. Homing endonucleases are site-specific, double-strand DNA endonucleases that promote the lateral transfer between genomes of their own coding region with flanking sequences, in a recombination-dependent process known as “homing.” Usually, homing endonucleases are encoded by an open reading frame within an intron or intein (Belfort et al. 2005; Chevalier and Stoddard 2001). Large inteins are bi-functional proteins, with a protein splicing domain, and a central endonuclease domain. Splicing-efficient mini-inteins have been engineered from large inteins by deleting the central endonuclease domain, demonstrating that the endonuclease domain is not involved in protein splicing (Chong and Xu 1997; Derbyshire et al. 1997; Shingledecker et al. 1998). The splicing domain is split by the endonuclease domain into N- and C-terminal subdomains, which contain conserved blocks of amino acids, with blocks A, N2, B, and N4 in the N-terminal subdomain, and blocks G and F in the C-terminal subdomain (Perler et al. 1997; Pietrokovski 1994, 1998) These domains can also be identified in mini-inteins (Fig. 2). The three-dimensional structures of naturally occurring mini-inteins and engineered mini-inteins reveal that the N- and C-terminal splicing domains form a common horseshoe-like 12-β-strand scaffold termed the Hedgehog/Intein (HINT) module (Ding et al. 2003; Hall et al. 1997; Klabunde et al. 1998; Koonin 1995; Perler 1998; Sun et al. 2005; Van Roey et al. 2007).Fig. 2

Bottom Line: They are found in organisms in all three domains of life, and in viral proteins.Intein excision is a posttranslational process that does not require auxiliary enzymes or cofactors.This review summarizes the catalytic activities and structures of inteins, and focuses on the advantages of some recent intein applications in molecular biology and biotechnology.

View Article: PubMed Central - PubMed

Affiliation: Institute of Technical Microbiology, Technical University Hamburg-Harburg, Kasernenstr. 12, 21073, Hamburg, Germany.

ABSTRACT
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. Intein excision is a posttranslational process that does not require auxiliary enzymes or cofactors. This self-excision process is called protein splicing, by analogy to the splicing of RNA introns from pre-mRNA. Protein splicing involves only four intramolecular reactions, and a small number of key catalytic residues in the intein and exteins. Protein-splicing can also occur in trans. In this case, the intein is separated into N- and C-terminal domains, which are synthesized as separate components, each joined to an extein. The intein domains reassemble and link the joined exteins into a single functional protein. Understanding the cis- and trans-protein splicing mechanisms led to the development of intein-mediated protein-engineering applications, such as protein purification, ligation, cyclization, and selenoprotein production. This review summarizes the catalytic activities and structures of inteins, and focuses on the advantages of some recent intein applications in molecular biology and biotechnology.

Show MeSH
Related in: MedlinePlus