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Molecular distortion of distamycin on binding to DNA as revealed by Raman spectroscopy
Author(s) -
Lu Dong Sheng,
aka Yasuomi,
Tsuboi Masamichi,
Nakamoto Kazuo
Publication year - 1990
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250210508
Subject(s) - netropsin , raman spectroscopy , dna , chemistry , crystallography , dihedral angle , stereochemistry , amide , pyrrole , polynucleotide , ring (chemistry) , molecule , minor groove , hydrogen bond , biochemistry , optics , physics , organic chemistry
Abstract The Raman spectra of distamycin and its complex with DNA were examined in both H 2 O and D 2 O solutions. To facilitate band assignments, Raman spectra of several small model compounds of distamycin were also obtained. On binding to DNA, the CO stretching band at 1620 cm −1 (amide I band) of distamycin was shifted upwards by 14 cm −1 , whereas a strong pyrrole‐ring stretching band at 1437 cm −1 was shifted downwards by 7 cm −1 in H 2 O. In addition, most of the Raman bands including amide I, II and III became narrower and sharper on binding to DNA. These results indicate that, in the free state, the dihedral angles around the CC and NC bonds connecting the pyrrole ring and the peptide chain of distamycin fluctuate near 0° (coplanar configruation), whereas in the bound state these angles are fixed and markedly shifted from 0°. Previous x‐ray and NMR studies on distamycin (netropsin)–DNA complexes show that such deviations occur when these drug molecules are bound in the minor groove of DNA. Molecular distortion of distamycin caused by interaction with other polynucleotides has also been elucidated by using such spectral characteristics as diagnosis.