No abstract

No abstract

Supramolecular DNA complexes were isolated from rat normal cells and murine tumors. The content of DNA bound lipids (cholesterol and its esters) was determined. The content of cholesterol esters is higher than that of free cholesterol; the lipid content in tumor cells is higher than in normal cells. Using the molecular mechanics approach, it is demonstrated for the first time that cholesterol and its esters with stearic, oleic, linoleic, and linolenic acids bind to the DNA minor groove more strongly than with the major groove. The calculated DNA binding energies of cholesterol and its esters depend on both the number of double bonds in the fatty acid residue and on the DNA nucleotide composition. The formation of stable complexes between cholesterol molecules and d(AT) rich oligonucleotides was demonstrated using bio logical microchip containing immobilized octadeoxyribonucleotides.

The existence of Pseudomonas aurantiaca DNA-bound fatty acids and lipids is presented in this work. The isolation of DNA was carried out by two different procedures, namely, phenol and detergent-based phenol isolation in order to prove the presence of DNA-bound lipids. The lipid content of DNA is expressed in terms of fatty acid profile. A high level of 16:0, 18:0 and 18:1 is characteristic for tightly bound DNA lipids. On the other hand, the fatty acids such as 14:1, iso14:0 and iso16:0 are found in trace amounts only in DNA lipid fraction, but these fatty acids are not found in the whole-cell lipids. Absolutely no 3-hydroxy fatty acids were found in DNA lipids. However, both C16 and C18 species represent the main fatty acids of whole-cell and DNA-bound lipids. The presence of DNA-bound lipids even under tough treatment of DNA allows to conclude that these lipids represent a special pool among cellular lipids.