Interactive Analysis System for Protein Splicing (ASFPS)

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Protein self-splicing is an autocatalysis reaction in which an intervening element (intein) is removed from the protein precursor at the protein level, resulting in the ligation of flanking host peptide (extein) with a native peptide bond (Xu, 1993; Cooper,1995; Xu,1996; Perler,1997A). Since the process self-splicing was first demonstrated in Saccharomyces in 1990 (Kane et al., 1990), there are 230 inteins listed in ASFPS. They were found in all domains of life, of which 110 are present in Archaea, 92 in Eubacteria, 22 in eukarya, and 6 in viruses.

Protein splicing is an intramolecular autocatalysis reaction. All of the required core elements for the reaction, except the first residue Cys/Ser of C-extein, are present within intein. However, multiple sequence comparison of inteins shows little conservation, which indicates that the activity of inteins is attributed by the arrangement of core elements. The mechanism of protein splicing is thought as sequential nucleophilic displacements, which lead the N-extein shifted to C-extein and finally ligate them through a peptide bond. The process is thought to involve in a series of transfers of electrons. Intein active site residues: N-terminal residue Cys, C-terminal dipeptide His-ASN and middle His**The in Block B, are close in 3D-structure to meet the requirements. Of them, the residues Cys/Ser/Thr at junction sites provide Thiol/Hydroxy group to occur nucleophilic attacks. Similar reactions are also found in other three families of protein: Hedgehog Protein, Glycosylasparaginase, and Histidine Decarboxylase proenzyme (Paulus, 2000, 1998).

For more information, click the following linkages:

1. Interactive Analysis System for Protein Splicing (ASFPS)

2. Protein splicing and other forms of protein autoprocessing

3. The bibliography of protein splicing and related protein autocatalysis

4. New identified or characterized inteins

5. Download all intein sequences in ASFPS

The information in ASFPS, including all spreadsheets and intein reports, are freely available at http://gene.fudan.sh.cn/intein3.nsf and can be printed or downloaded to a local disk.

In order for the ASFPS administrators to keep track of the uses of ASFPS as well as to ensure future funding for the system, it would be appreciated for any study or publication that uses ASFPS to cite the following paper as a reference:


J. Xie, X. Hua, Q. Huang, T. Zhou ,C.-Q. Wu, and L. Yu.
ASFPS: An Interactive Analysis System for Protein Splicing: Compilation and Characterization of Inteins. (Submitted).

Database updated 2006-12-30.

Any suggestions are welcomed and please send to Jun Xie by Email: xiejun@fudan.edu.cn