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Far‐infrared absorption of nucleotides and poly(I)·poly(C) RNA
Author(s) -
Beetz C. P.,
Ascarelli G.
Publication year - 1982
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.360210808
Subject(s) - chemistry , nucleotide , ribose , polynucleotide , absorption (acoustics) , sharpening , infrared spectroscopy , ring (chemistry) , absorption spectroscopy , spectral line , crystallography , infrared , adsorption , optics , organic chemistry , physics , biochemistry , astronomy , computer science , computer vision , gene , enzyme
We have measured the ir absorption of 5′CMP, 5′IMP, and poly(I)·poly(C) from ∼25 to ∼500 cm −1 . From a comparison of the data with the previously measured absorption of the corresponding nucleosides and bases we can identify several “lines” associated with the deformation of the ribose ring. Out‐of‐plane deformation of the bases contributes strongly to vibrations near 200 cm −1 . The same ribose vibrations observed in the nucleotides are found in poly(I)·poly(C). They sharpen with increasing water absorption. A study of the spectra of poly(I)·poly(C) as a function of the adsorbed water indicates that water does not contribute in a purely additive fashion to the polynucleotide spectrum but depends on the conformation of the helix. However, the only spectral feature that shifts drastically with conformation is near 45 cm −1 . Measurements at cryogenic temperatures indicate some sharpening of the spectrum of poly(I)·poly(C). Instead, no sharpening is observed in the spectrum of the nucleotides. Shear degradation of poly(I)·poly(C) produces significant spectral changes in the 200‐cm −1 region and sharpening of the features assigned to the low‐frequency ribose‐ring vibrations.