Optical Response of the Polynucleotides-Proteins Interaction

Abstract

The optical absorption, fluorescence, and phosphorescence spectra of RNAs and oligonucleotides of different origin, as well as their mixtures with human albumin are investigated. It is confirmed that the energy structures of DNA, RNA, and complex protein macromolecules are determined mainly by the individual properties of their π-electron systems. The positions of the RNA excited singlet and triplet energy levels obtained by authors' previous work are determined more precisely. It is shown that mainly adenine bases are traps for mobile triplet excitons in RNA (contrary to DNA, in which AT complexes are the triplet traps). The spectral manifestation of the RNA/oligonucleotides-albumin interaction is studied. It turns out that namely the phosphorescence spectra of these compounds due to their sharp structure at 4.2 K are the most suitable for the study of the RNA-albumin interaction. The phosphorescence spectra of albumin-2′5′A₃ solvents manifest the penetrative binding of 2′5′A₃ to an albumin macromolecule. The obtained data show that at least a weak non-penetrative binding of RNA to human albumin can exist.

Keywords:

• Human albumin
• oligoadenylate
• phosphorescence
• RNA
• triplet excitations