Melting Calorimetry of Rat Liver Nuclei in the Presence of Magnesium Ions

Kolomijtseva, G.Y.; Prusov, A.N.; Kolomijtseva, E.A.; Smirnova, T.A.

Авторы: Kolomijtseva G.Ya, Prusov A.N., Kolomijtseva E.A., Smirnova T.A.
Журнал: Biophysics
Том: 68
Номер: 2
Год издания: 2023
Издательство: Maik Nauka/Interperiodica Publishing
Местоположение издательства: Russian Federation
Первая страница: 272
Последняя страница: 281
Оригинальные версии: "Калориметрия плавления ядер клеток печени крысы в присутствии ионов магния"
DOI: 10.1134/s0006350923020082
Аннотация: Differential scanning calorimetry (DSC) was used to determine the thermodynamic parameters of intranuclear chromatin decondensation induced in rat liver nuclei by decreasing the concentration of magnesium ions from 5 to 0 mM. Core histones, relaxed DNA, and topologically constrained DNA were shown to be involved consecutively in chromatin melting in a temperature range of 70–100°C. Both Tm and ΔH of individual peaks proved also to depend on the Mg2+ concentration in the buffer. In nuclei with condensed chromatin, Mg2+ ions used at 5 mM significantly increased Tm of core histones (by ~7°C) as compared with their Tm in unfolded chromatin, but decreased Tm of both relaxed and constrained nuclear DNA (by ~2.5 and ~7.5°С, respectively). The melting enthalpy of the peaks significantly increased in the presence of Mg2+. A decrease in the molecular weight of intranuclear DNA abolished the stabilizing effect of Mg2+ on core histones. A new peak with Tm above 100°С became detectable when the Mg2+ concentration exceeded 5 mM, possibly reflecting the thermal behavior of some Mg-induced aggregates. Possible mechanisms underlying the thermal behavior of chromatin within the nucleus are discussed.
Добавил в систему: Прусов Андрей Николаевич

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Melting Calorimetry of Rat Liver Nuclei in the Presence of Magnesium Ionsстатья

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