Search academic texts

Information × Registration Number 0214U000598, 0113U005319 , R & D reports Title Delivery systems based on transport proteins, hydroborane clusters and clathrochelates for boron neutron capture therapy popup.stage_title Head El'ska Ganna Valentynivna, Доктор біологічних наук Registration Date 01-04-2014 Organization Institute of Molecular Biology and Genetics of NASU popup.description2 In the terms of current project the interaction between macrocyclic compounds (closo-borates and clathrohelates, which were received from the Russian partner) and proteins, particularly bovine (BSA) and human (HSA) serum albumins was studied. We estimate the binding by the changes of protein fluorescent properties in absence and in presence of closo-borates and clathrohelates using steady-state and time-reserved spectroscopy. It is shown that (1) clathrohelates most intensively quench fluorescence of albumins, (2) among closo-borates the arylamino substituted derivatives noticably decrease the protein fluorescence. Hence closo-borates and clathrohelates bind to albumins, aromatic substituents in closo-borates structure enhance the binding and clathrohelates strongly bind to albumins, than closo-borates despite clathrohelates large sizes. It was also shown that (3) quenching of the BSA fluorescence is more intensive than that of HSA. This could be explained by the fact that BSA contains two tryptophan residues, one of them is placed close to the surface, while in HSA contains only one tryptophan residue "hidden" in the hydrophobic medium. It was also shown that (4) the presence clathrohelates with six and two carboxy groups, and also aromatic substituents of closo-borates decrease fluorescence lifetimes of both albumins. This can be explained by changes in protein conformation upon the ligand binding, by dynamic quenching and (in the clathrohelates case) by excitation energy transfer from tryptophan to ligand; (5) clathrohelates influence on the lifetimes is much stronger than that of closo-borates, this correlates well with the noticeable effect of these ligands on the fluorescence intensity of proteins. (6) Clathrohelates with six COOH - groups effect on the BSA fluorescence excitation lifetime stronger than clathrohelates with two carboxyl groups, whereas the influence of all studied clathrohelates on HSA is the same. Thus, investigated macrocyclic compounds are capable to form high stable complexes with transport blood proteins. The formation of such complexes can change the protein molecule conformation and fluorescent properties of this changing are the "indicator" of this process. At the same time, iron clathrohelates bind to albumins more effectively than boron compounds - closo-borates. Therefore, iron (II) clathrohelates are considered as promising molecular platform for design of clusters with high contain of boron atoms, as potential agents for BNCT. Product Description popup.authors Варзацький О.А. Ковальська В.Б. Лосицький М.Ю. Ярмолюк С.М. popup.nrat_date 2020-04-02 Close