| dc.contributor.author | Wu, Hong. | en_US |
| dc.date.accessioned | 2014-10-21T12:38:17Z | |
| dc.date.available | 1998 | |
| dc.date.issued | 1998 | en_US |
| dc.identifier.other | AAINQ36595 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55608 | |
| dc.description | Inteins are protein sequences embedded in-frame within precursor protein sequences and excised during a maturation process termed protein splicing. Protein splicing is a post-translational event involving precise excision of the intein sequence and concomitant ligation of the flanking sequences (N- and C-exteins) by a normal peptide bond. | en_US |
| dc.description | The dnaB gene of cyanobacterium Synechocystis sp. strain PCC6803 was shown to encode a DNA helicase that has a 429-aa intervening sequence. This intervening sequence was identified as an intein, based on sequence analysis and a demonstration of protein splicing with or without the native exteins when tested in E. coli cells. A centrally located 275 aa sequence (residues 107--381) of this intein was deleted without loss of the protein splicing activity, resulting in a functional mini-intein of 154 aa. This mini-intein was then split into two separate fragments: a 106-aa N-terminal fragment containing intein motifs A and B, and a 48-aa C-terminal fragment containing intein motifs F and G. These two intein fragments, when produced in E. coli cells, carried out efficient protein trans-splicing. These results indicate that the N- and C-terminal regions of the Ssp DnaB intein, whether covalently linked with each other or not, can come together through non-covalent interactions to form a protein splicing domain that is functionally sufficient and structurally independent from the centrally located endonuclease domain of the intein. Mutagenesis of the 154-aa mini-intein revealed some internal residues that are involved in the protein splicing activity of this intein. | en_US |
| dc.description | A naturally occurring split intein, capable of protein trans -splicing, was 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 consists of a N-extein sequence followed by a 123-aa intein sequence, while the dnaE-c product consists of a 36-aa intein sequence followed by a C-extein sequence. The N- and C-extein sequences together reconstitute a complete DnaE sequence, which is interrupted by the intein sequences inside the domain that interacts with the beta and tau subunits of DNA polymerase III. The two intein sequences together reconstitute a split mini-intein that not only has intein-like sequence features but also exhibited protein trans-splicing activity when tested in E. coli cells. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1998. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Molecular. | en_US |
| dc.subject | Biology, Microbiology. | en_US |
| dc.title | A study of two cyanobacterial inteins. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
