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The intercalation of imidazoacridinones into DNA induces conformational changes in their side chain.

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Mazerski J., Muchewicz K.

2000

vol. 47

issue 1

65-78

Imidazoacridinones (IAs) are a new group of highly active antitumor compounds. The intercalation of the IA molecule into DNA is the preliminary step in the mode of action of these compounds. There are no experimental data about the structure of an intercalation complex formed by imidazoacridinones. Therefore the design of new potentially better compounds of this group should employ the molecular modelling techniques. The results of molecular dynamics simulations performed for four IA analogues are presented. Each of the compounds was studied in two systems: i) in water, and ii) in the intercalation complex with dodecamer duplex d(GCGCGCGCGCGC)2. Significant differences in the conformation of the side chain in the two environments were observed for all studied IAs. These changes were induced by electrostatic as well as van der Waals interactions between the intercalator and DNA. Moreover, the results showed that the geometry of the intercalation complex depends on: i) the chemical constitution of the side chain, and ii) the substituent in position 8 of the ring system.

Quercetin influences BSA alpha-helical structures of native, ACR- and NaNO2-modified BSAs

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Rorbach-Dolata A., Żurawska-Płaksej E., Piwowar A.

Acta Poloniae Pharmaceutica - Drug Research

2018

vol. 75

issue 6

1339-1346

Quercetin (QUE) is a plant flavonoid with a multifarious spectrum of properties. It is a prominent component of the human diet, considered to be safe and beneficial for human health. Acrylamide (ACR) and sodium nitrate III (NaNO2) are also present in the diet and may demonstrate adverse and toxic effects on the macromolecules and tissues of the human organism. Albumin, the most abundant blood protein, is the most susceptible to the action of various exogenous factors, which may lead to structural damage and functional disturbances. The aim of this study was to estimate ACR- and NaNO2-induced changes in the secondary structure of bovine serum albumin (BSA), using circular dichroism (CD), and to determine the impact of quercetin on these modifications. BSA was incubated with ACR and NaNO2 solutions in the absence and presence of QUE in two different concentrations (3 mM and 500 µM), and changes in albumin alpha-helical structure were determined by CD. BSA secondary structure was vulnerable to alterations upon treatment with acrylamide and NaNO2, as well as quercetin. QUE, depending on concentration and incubation time, caused a decrease of around 13-19% in the alpha-helix content of BSA molecules, but also prevented the changes in the protein alpha-helical structure initiated by ACR and NaNO2. The most spectacular inhibition was revealed for QUE in lower concentrations after 24h of incubation with NaNO2. Although QUE reveals protective effect towards albumin modifications, it is difficult to unambiguously define whether this effect is advantageous, because quercetin itself causes alterations in BSA structure.

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1 Acta Biochimica Polonica

1 Acta Poloniae Pharmaceutica - Drug Research

1 2018

1 2000

1 Mazerski J.

1 Muchewicz K.

1 Piwowar A.

1 Rorbach-Dolata A.

1 Żurawska-Płaksej E.

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The intercalation of imidazoacridinones into DNA induces conformational changes in their side chain.

Quercetin influences BSA alpha-helical structures of native, ACR- and NaNO2-modified BSAs