Serena Aceto, Antimo Di Maro, Barbara Conforto, Gesualdo G. Siniscalco, Augusto Parente, Pasquale Delli Bovi, Luciano Gaudio
Nicking activity on pBR322 DNA of ribosome inactivating proteins from Phytolacca dioica L. leaves
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 [?-32P]dCTP and [?-32P]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.
Biological Chemistry, Walter de Gruyter
Print ISSN: 1431-6730
Volume: 386, 04/2005
Pages: 307 - 317
Show full article (external site)
Show all available items of this journal
Search
