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- Title
Nicking activity on pBR322 DNA of ribosome inactivating proteins from Phytolacca dioica L. leaves.
- Authors
Aceto, Serena; Di Maro, Antimo; Conforto, Barbara; Siniscalco, Gesualdo G.; Parente, Augusto; Delli Bovi, Pasquale; Gaudio, Luciano
- Abstract
Ribosome-inactivating proteins isolated from Phytolacca dioica L. leaves are rRNA-N-glycosidases, as well as adenine polynucleotide glycosylases. Here we report that some of them cleave supercoiled pBR322 dsDNA, generating relaxed and linear molecules. PD-L1, the glycosylated major form isolated from the winter leaves of adult P . dioica plants, produces both free 3′-OH and 5′-P termini randomly distributed along the DNA molecule, as suggested by labelling experiments with [α- 32 P]dCTP and [γ- 32 P]dATP. Moreover, when the reaction is carried out under low-salt conditions, cleavage is observed mainly at a specific site, located downstream of the ampicillin resistance gene (close to position 3200), ending with the deletion of a fragment of approximately 70 nucleotides. This cleavage pattern is similar to that obtained under the same conditions with mung bean nuclease, a single-strand endonuclease. Furthermore, pBR322 DNA treated with PD-L1 shows reduced transforming activity with E . coli HB101 competent cells in comparison to untreated control plasmid DNA.
- Subjects
DNA topoisomerase I; OMBU; PHYTOLACCA; PROTEINS; GENES
- Publication
Biological Chemistry, 2005, Vol 386, Issue 4, p307
- ISSN
1431-6730
- Publication type
Article
- DOI
10.1515/BC.2005.037