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 p-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 0 5 0 A 3 solvents manifest the penetrative binding of 2 0 5 0 A 3 to an albumin macromolecule. The obtained data show that at least a weak non-penetrative binding of RNA to human albumin can exist.

Spectroscopic Studies of Infectious Pancreatic Necrosis Virus, Its Major Capsid Protein, and RNA

“…One can see distinct peaks at 3.1, 2.9, 2.7, and 2.5 eV. This electronic-vibrational structure of the spectrum may be attributed to that of the phosphorescence of adenine, because this nucleotide has the lowest first triplet energy level among all RNA nucleotides and because of the fact that the triplet excitation can be freely transferred along the RNA macromolecule [5,17]. Some discrepancy in the peak positions in RNA and adenine phosphorescence spectra may have the same causes as described above.…”

“…The IPNV RNA fluorescence spectrum resembles neither RNA nucleotide one (the former has too short peak wavelength and too small half-width compared to those of either RNA base) [5], although other RNA fluorescence spectra reported in the literature can be modeled as a linear combination of fluorescence spectra of RNA nucleotides, for example, rGMP and rCMP [17]. There is a reason to believe that the different peak positions and half-widths of the RNA fluorescence (and phosphorescence) spectra in the literature and in our study may be attributed to the dependence of the shape and peak position of emission spectra of a solution of either proteins or amino or nucleic acids or nucleotides on the solvent and its pH index [16,18].…”

“…It has been confirmed that the energy structures of DNA, RNA, and complex protein macromolecules are determined mainly by the individual properties of their -electron systems such as DNA or RNA nucleotides or aromatic amino acids (tryptophan, tyrosine, and phenylalanine), which are centers of intense UV absorption and fluores-cence ( > 200 nm). Some success has been reached in modeling the spectra of large and complex native biological macromolecules by the spectra of relatively small -electron-containing model compounds [5]. At the same time, it is known that the peak positions of absorption bands and, even to a greater extent, fluorescence bands and the fluorescence quantum yield are highly dependent on the protein structure and the local environment (neighboring amino acid residues and solvent molecules) [2].…”

Minimally invasive photoacoustic imaging: Current status and future perspectives

“…1a) [[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18]]. For example, in the ultraviolet range from 180 nm to 400 nm, strong light absorption of DNA and RNA enables the visualisation of cell nuclei without staining [[19], [20], [21], [22]]. In the visible range from 500 nm to 600 nm, and the near-infrared range from 700 nm to 900 nm, haemoglobin is commonly targeted as the primary chromophore to provide both structural and functional information of microvasculature [[14], [15], [16]].…”

“…1Endogenous tissue chromophores in photoacoustic imaging. (a) Optical absorption spectra of the main tissue chromophores, including DNA (data adapted from [20]), RNA (data adapted from [22]), oxyhaemoglobin, deoxyhaemoglobin (150 g L −1 ), melanin (data from https://omlc.org/spectra/), water and lipid (data adapted from [18]). (b) Ultraviolet localised photoacoustic (PA) image of a fibroblast cell with lipids, protein and nucleic acids contents shown in pseudo-coloured blue, green and red, respectively.…”