[Specific DNA cleavage by an analog of netropsin containing a copper(II) chelating peptide Gly-Gly-His].
Experimental data are reported on DNA-cleaving activity of the synthetic netropsin analogs consisting of the two N-propylpyrrole carboxamide units linked covalently through two or three glycine residues to a copper-chelating tripeptide glycyl-glycyl-L-histidine. Incubation of DNA restriction fragment and netropsin analog in the presence of ascorbate, hydrogen peroxide and Cu2+ ions resulted in selective cleavage of the DNA at or near the preferred sites for binding of netropsin analog. A similar cleavage pattern is observed after X-ray irradiation of DNA complexes with netropsin analogs tethered with Cu2+ ions. The cleavage patterns are found to be dependent on the length of the connecting chain between the histidine-containing tripeptide and netropsin analog. The netropsin analog containing three glycine residues in the connecting chain, but not the analog with a shorter linker chain, can generate an intense cleavage of one of the two polynucleotide chains at a position corresponding to the presumed binding site for the dimeric ligand species. More than 50% of the total DNA can be cleaved at this position after X-ray irradiation. From analysis of the nucleotide sequences surrounding the preferred cleavage site on several DNA fragments we found that the consensus is 5'-TTTTNCA*AAA-3', where N is an arbitrary nucleotide. The Cu(2+)-mediated cleavage of DNA occurs at the second adenine (indicated by an asterisk) from the 5'-end of the sequence. The greatest cleavage activity is observed when the molar ratio of Cu2+ to the netropsin analog is equal to 0.5. Evidently, the Cu(2+)-ligated and unligated oligopeptide species interacts with each other to form a heterodimer bound to DNA at the cleavage site. To test the validity of this model we have studied the binding of unligated netropsin analog and netropsin analog complexed with Cu2+ ion to a self-complementary oligonucleotide 5'-GCGTTTTGCAAAACGC-3'. It is found that binding of Cu(2+)-ligated netropsin analog to the DNA oligomer preincubated with unligated form of the oligopeptide is a cooperative process for which interactions between the two bound ligands are responsible. The cooperativity parameter is estimated to be on the order of factor 6. Finally, a model is proposed in which a heterodimer stabilized by interligand beta-sheet binds in the minor DNA groove.
Grokhovskiĭ
S L
SL
Zhuze AL
Nikolaev
V A
VA
Zubarev
V E
VE
Surovaia
A N
AN
Zhuze
A L
AL
Chernov
B K
BK
Sidorova
N Iu
NIu
Zasedatelev
A S
AS
Gurskiĭ
G V
GV
D000595:Amino Acid Sequence; D001483:Base Sequence; D002614:Chelating Agents; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004586:Electrophoresis; D008969:Molecular Sequence Data; D009429:Netropsin / Q000031:analogs & derivatives / Q000494:pharmacology*; D009842:Oligopeptides / Q000737:chemistry*
D002614:Chelating Agents; D009842:Oligopeptides; D009429:Netropsin; C037026:diglycyl-histidine; D003300:Copper; D004247:DNA
Spetsificheskoe rasshcheplenie DNK analogom netropsina, soderzhashchim khelatiruiushchiĭ ion medi(II) peptid Gly-Gly-His.