Inteins (protein introns) are internal portions of protein sequences that are posttranslationally excised while the flanking regions are spliced together, making an additional protein product. Inteins have been found in a number of homologous genes in yeast, mycobacteria, and extreme thermophile archaebacteria. The inteins are probably multifunctional, autocatalyzing their own splicing, and som...

Protein splicing is a post-translational reaction facilitated by an intein, or intervening protein, which involves the removal of the intein and the ligation of the flanking polypeptides, or exteins. A DNA polymerase II intein from Pyrococcus abyssi (Pab PolII intein) can promote protein splicing in vitro on incubation at high temperature. Mutation of active site residues Cys1, Gln185, and Cys+...

A split intein capable of protein trans-splicing is identified in a DnaE protein of the cyanobacterium Synechocystis sp. strain PCC6803. The N- and C-terminal halves of DnaE (catalytic subunit alpha of DNA polymerase III) are encoded by two separate genes, dnaE-n and dnaE-c, respectively. These two genes are located 745,226 bp apart in the genome and on opposite DNA strands. The dnaE-n product ...

Inteins are intervening sequences that splice as proteins, not RNA. InBase, the New England Biolabs Intein Database (http://www.neb. com/neb/inteins.html), is a comprehensive on-line database that includes the Intein Registry, along with detailed information about each intein and its host protein, tabulated comparisons and a comprehensive bibliography including papers in press.

Inteins catalyze a protein splicing reaction to excise the intein from a precursor protein and join the flanking sequences (exteins) with a peptide bond. In a split intein, the intein fragments (I(N) and I(C)) can reassemble non-covalently to catalyze a trans-splicing reaction that joins the exteins from separate polypeptides. An atypical split intein having a very small I(N) and a large I(C) i...

Inteins are self-splicing protein elements that are mobile at the DNA level and are sporadically distributed across microbial genomes. Inteins appear to be horizontally transferred, and it has been speculated that phages may play a role in intein distribution. Our attention turns to mycobacteriophages, which infect mycobacteria, where both phage and host harbor inteins. Using bioinformatics, my...

A dnaB gene encoding a homologue of the Escherichia coli DNA helicase DnaB was cloned and sequenced in the thermophilic eubacterium Rhodothermus marinus, predicting a DnaB protein that harbors an intein. This DnaB intein is 428 amino acid residues long, has several putative intein sequence motifs (including two putative endonuclease motifs), and is capable of protein splicing when produced in E...

Split-protein systems have emerged as a powerful tool for detecting biomolecular interactions and reporting biological reactions. However, reliable methods for identifying viable split sites are still unavailable. In this study, we demonstrated the feasibility that valid circular permutation (CP) sites in proteins have the potential to act as split sites and that CP prediction can be used to se...

A survey of a vast range of mycobacterial strains led us to discover a new Pps1 intein allele in Mycobacterium gastri which differs from those of Mycobacterium tuberculosis and Mycobacterium leprae in both its sequence and insertion site. While little is known about Pps1, except that it belongs to the YC24 family of ABC transporters, we show that, unlike the other inteins described so far from ...

This research uses inteins, a type of mobile genetic element, to infer patterns of gene transfer within the Halobacteria. We surveyed 118 genomes representing 26 genera of Halobacteria for intein sequences. We then used the presence-absence profile, sequence similarity and phylogenies from the inteins recovered to explore how intein distribution can provide insight on the dynamics of gene flow ...