(1) Background: It is known that RNA in Na+ salt form has only immunomodulatory activity, and in acid form additionally acquires anti-inflammatory activity and in combination with D-mannitol acquires an even broader antiviral effect. The study aimed to study the ability of adenosinmonophosphat (AMP) and oligoribonucleotides (ORNs) in acid and salt form and in combination with D-mannitol to affect the conformation and fluorescence of interferon (INF) α-2b and to determine the energy parameters of these interactions. (2) Methods: spectroscopy (time pulsed and fluorescence), isothermal nanocalorimetry. (3) Results: AMP and ORNs in acid form and complex with D-mannitol bind more strongly to interferon α-2b than salt analogues. In the interaction of interferon α-2b and acid AMP and especially in complex with D-mannitol, the reaction occurs exothermically and change in conformational mobility INF by increasing the content of disordered regions. When INF α-2b interacts with salt AMP, the reaction occurs endothermically, and probably the salt form increases the conformational stiffness of INF α-2b. The greater efficiency of nonradiative energy transfer from INF α-2b to acid AMP has been shown, due to the closer distance between molecules. (4) Conclusions: AMP in acid form interacts more actively and increases the conformational mobility of INF, at a greater relative distance and with less Gibbs energy compared to the salt form, which probably causes the appearance of additional biological properties of acidic AMP.

The biological activity of oligoribonucleotide (ORN) based drugs studied very actively at the same time. However, at the same time, it is of great importance to study their biophysical particularly spectral properties.As the samples, we worked with the "Nuclex", pharmaceutical drugs that are based on a combination of ORN and alcohol sugar D-mannitol (D-M), and the main components of these drugs (active substance -ORN and excipient -D-M). We have measured the UV-Vis absorption, fluorescence, and fluorescence excitation spectra of drugs and their components dissolved in the water under the room temperatures.In the course of our research, we found the autofluorescence centers of Nuklex and identified the possibility of forming complexes between ORN and D-M.

A novel enhanced fluorescent sensor system for zearalenone (ZON) determination in flour samples is presented. The ZON-selective molecularly imprinted polymer (MIP) films were developed with a computational modelling method and...

Aim. To study the ability of yeast RNA oligoribonucleotides (ORNs) and their complexes withD-mannitol to influence the conformation and thermal stability of interferon (INF) α-2b. Methods. The ability of oligoribonucleotide drugs to bind to INF α-2b was studied using its fluorescence quenching method. The effect of ORN drugs on protein stability was studied by analyzing the thermal stability of INF. To confirm their influence on the conformation of the INF, we investigated the spectra of circular dichroism. Results. The ORN complexes with D-mannitol, due to their better protein binding, have been shown to have a much higher effect on the conformation and thermal stability of interferon α-2b than ORN. ORNs and their complexes with D-mannitol also increase the thermal stabilization of interferon. The addition of ORN and ORN with D-mannitol to INF leads to a decrease in the content of α-helical components in the protein structure and an increase in β-components and unstructured parts of the protein molecule. Addition of the ORN complex: D-mannitol, unlike the ORN, changes the architecture of the tertiary INF structure. Conclusions. Therefore, the ORN complexes with D-mannitol have a much higher effect on the conformation and thermal stability of interferon α-2b than the parent drug ORN. The more specific binding of oligonucleotides can probably explain this in the presence of mannitol to the protein. ORNs and ORN complexes with D-mannitol also increase the thermal stabilization of interferon by 2 and 1.8 °C, respectively. The addition of ORNs and ORN complexes with D-mannitol leads to a decrease in the content of α- helical components in the protein structure and an increase in antiparallel β-sheets, β-turns, and unstructured elements. In the presence of mannitol in the ORN molecule, the structure of INF changes more intensively. Addition of ORN complexes: D-mannitol to INF, unlike ORN, changes the architecture of the tertiary protein structure from a 2-layer sandwich to an alpha-beta complex.Keywords: oligonucleotides; interferon; mannitol; secondary protein structure.