On the excited‐state geometry of the adenine residue as revealed by a preresonance Raman effect

Abstract

The Raman spectrum of ~-adenosine-5'-phosphoric acid has been observed in its aqueous solution with 6471, 5145, 4880, 4579, 3638, and 3511 8, excitation. An examination of the manner of increase of the intensities of the Raman lines at 1580 and 1484 cm-l of the adenine residue indicated that the electronic excited state corresponding to a weak absorption band at 276 nm is responsible for these Raman scatterings. This idea has been supported by a similar examination of the Raman spectrum of /l-adenosine-3',5'-cyclic phosphoric acid and an examination of the effect of temperature on the Raman spectra of poly rA and poly(rA-rU). A discussion is included of the geometrical structure of the adenine residue in its lowest-singlet electronic excited state, based on the vibrational structure of the fluorescence spectrum, the result of a normal coordinate treatment, and the result of a semiempirical Pariser-Parr-Pople calculation, as well as the Raman data.

Initial Excited-State Structural Dynamics of 9-Methyladenine from UV Resonance Raman Spectroscopy

“…This band is close to a similarly assigned band found at 1340 cm À1 for adenine. 53 There is a number of medium intensity bands found at 1208, 1254, 1437, 1498, 1537, and 1603 cm À1 , while weak bands in 9-MeA occur at 535, 601, 728, 1010, and 1680 cm À1 .…”

Recognition of base pairs by polar peptides in double stranded DNA

“…These spectral variations involve on the one hand the N 3H and C2 = 0 region of thymine, on the other hand the N3 region of adenine (33). These groups are located in the narrow groove of DNA, and as in the preceding case, according to a Corey-Pauling model, we assume the following mode of interaction -Three electrostatic interactions can-exist between the NH + groups of 3 arginyl-arginine and the negatively charged phosphates of the phosphate chain, two on one strand, the third on the opposite strand, along the narrow groove of DNA.…”

Nucleic acid derivatives studied by preresonance and resonance Raman spectroscopy in the ultraviolet region

“…Each pulse or pulse train repaired by a given number in the lower part has its corresponding number at the right place in the upper part. At each laser flash (5) (triggered by the laser clock (l)), two data are taken into account: the first one is the photomultiplier pulse amplitude (7) corresponding to the Raman signal, the second one is the pulse amplitude (6) provided by a monitoring photomultiplier illuminated by a very weak ray of incident light. Both amplitudes (which are considered proportional to the number of incident photons) are converted after adequate delay (8) into numbers N1 and N2 respectively by analog-digital convertors (ADC).…”