Yukio Matsuoka

Linear dichroism study of 9-substituted acridines in stretched poly(vinyl alcohol) film

Abstract Polarized absorption spectra have been measured on acridine, acridone and the 9-aminoacridinium and 9-amino-10-methylacridinium cations in stretched poly(vinyl alcohol) films, in the absorption region 220–500 nm, and corresponding transition moment directions were determined. The acridine derivatives should be suitable as bio-structural probes, as they provide transitions which are polarized exactly parallel to the two symmetry axes in the molecular plane.

On the structure of active chromatin: A flow linear dichroism study of chromatin fractionated by nuclease digestion

Nuclei from Ehrlich ascites cells were treated with micrococcal nuclease or DNase I and extracted with 1 mM EDTA. The chromatin fraction released by this procedure showed positive flow linear dichroism (LD) at low salt (2 mM NaCl) while the non‐released fraction had negative LD. Furthermore, the chromatin structure responsible for the positive LD was found to be labile: The LD was reduced by heat (37°C) or RNase treatment and inverted to a negative LD by electric fields (10 kV/cm) and by the presence of DNA binding dyes.

Nucleic acid-metal interactions. III. Complexes of Ag(I) with adenine and 1-methyladenine from studies of UV and IR dichroic spectra

Attempts to characterize nucleic acid-silver interactions raise questions about how the free nucleic acid bases interact with silver ions in dilute aqueous solution. Studies of ultraviolet and infrared dichroism lead to the conclusion that with silver(I) ions in dilute solution adenine forms linear polymers, whereas 1-methyladenine forms dimers. The composition and structure of the complexes are further discussed against the background of the spectroscopic results.

Transition moment directions of some important in-plane vibrations of uracil, thymine and cytosine. A fixed partial charge model calculation

Abstract Transition moment directions for the double-bond region vibrations of uracil, thymine and cytosine are calculated using the fixed partial charge model approximation. The coupling between the two carbonyl bonds and the carbon—carbon double bond in uracil and thymine is sensitive to the choice of the corresponding stretching force constants. The transition moment directions are correspondingly changed, thus, in principle, enabling the quantitative determination of coupling between the vibrations from linear dichroism measurements.

Formation of silver–adenine long-chain aggregates in neutral aqueous solution: study of flow linear dichroism

The existence of long, linear adenine–silver clusters in neutral, very dilute solutions has been demonstrated by flow linear dichroism.