The interaction of copper tetrakis(4-N-methylpyridyl) porphine with polynucleotides studied by ultraviolet resonance Raman spectroscopy.
Resonance Raman spectra are reported for poly[dA.dT]2, poly[dA].poly[dT], poly[dG.dC]2, poly[dG].poly[dC], poly[dA.dC].poly[dG.dT] and Calf Thymus DNA in interaction with the porphyrin Cu(TMpy-P4). The spectra were obtained under conditions of low salinity and a ratio of porphyrin molecules to nucleotide base pairs of r = 0.05, with an excitation wavelength of 257 nm. The differences between the spectra in interaction with Cu(TMpy-P4) and those of the unmodified nucleic acids are interpreted in terms of the structural changes imposed by the porphyrin. Two different binding modes have been reported in previous studies, a 5'CG-3' specific intercalative mode and an A-T specific outside binding mode. Our results suggest that this latter mode may show a preference for A-A or T-T sites. Furthermore a transition in structure, while remaining within the B-form family of structures, is indicated for both poly[dA].poly[dT] and poly[dG.dC]2 upon addition of Cu(TMpy-P4).
Wheeler
G V
GV
Institut Curie, Section de Recherche, Paris, France.
Chinsky
L
L
Miskovsky
P
P
Turpin
P Y
PY
D003300:Copper; D007364:Intercalating Agents / Q000737:chemistry*; D008665:Metalloporphyrins / Q000737:chemistry*; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000737:chemistry*; D011119:Polynucleotides / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D014466:Ultraviolet Rays
D007364:Intercalating Agents; D008665:Metalloporphyrins; D009711:Nucleotides; D011119:Polynucleotides; C078184:copper tetra(4-N-methylpyridyl)porphine; D003300:Copper