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Ir and Raman spectroscopic studies on coulombic interaction between water‐soluble porphyrins and nucleic acids
Author(s) -
aka Y.,
Lu D. S.,
Dwivedi A.,
Strommen D. P.,
Nakamoto K.
Publication year - 1990
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360290611
Subject(s) - nucleic acid , chemistry , raman spectroscopy , group (periodic table) , dna , fourier transform infrared spectroscopy , crystallography , spectroscopy , oxygen , stereochemistry , analytical chemistry (journal) , organic chemistry , biochemistry , chemical engineering , physics , quantum mechanics , optics , engineering
We have shown previously that the N‐methylpridyl group vibrations of water‐soluble porphyrins, M(TMpy‐P4), are shifted to lower frequencies (0.5–2.6 cm −1 ) as a result of coulombic interaction between the N + ‐CH 3 group of M(TMpy‐P4) and the PO 2 group of a nucleic acid. We have now turned over our attention to the effect of this coulombic interaction on the PO 2 group vibrations of nucleic acids. Using Fourier transform ir and Raman spectroscopy, we found that the ν a (PO 2 ) at 1221 cm −1 is shifted 12 ∼ 17 cm −1 to higher frequencies, whereas the ν s (PO 2 ) at 1087 cm −1 is shifted 18 ∼ 26 cm −1 to lower frequencies, when DNA is mixed with M(TMpy‐P4). These results indicate that the N + ‐CH 3 group of M(TMpy‐P4) interacts preferentially with one of the two oxygen atoms of the PO 2 group of the DNA duplex.