Thermal denaturation of nucleosomal core particles
Thermal denaturation of nucleosomal core particles
复制标题
核小体核心颗粒的热变性
DOI：
10.1093/nar/5.1.139
复制
发表时间：
1978
影响因子：
14.9
通讯作者：
H. Klump
中科院分区：
文献类型：
--
作者：
W. Weischet;K. Tatchell;K. Holde;H. Klump
Thermal denaturation of very homogeneous preparations of core particles from chicken erythrocyte chromatin is studied by several techniques. The change in absorbance, which is very closely paralleled by changes in heat capacity, which is very closely paralleled by changes in heat capacity, is a biphasic process with inflexions at 60 degrees C and 74 degrees C. In contrast, isolated DNA of the same length denatures in a single transition around 44 degrees C. Monitoring the circular dichroism of the cores during thermal denaturation reveals biphasic changes in the secondary structure of the DNA, preceding the base unstacking by 10 degrees C in the first and 3 degrees C in the second phase. However, measurable alterations in the secondary structure of the histones are confined to the second phase with a melting temperature at 71 degrees C. Increase in the ionic strength of the buffer from 1 mM to 10 mM leads to almost monophasic melting curves as measured by absorbance and CD, while not causing any measurable conformational changes at room temperature. The melting of core particles is interpreted as a denaturation of about 40 base pairs in the first phase, followed by a massive breakdown of the native structure of a tight histone-DNA complex, which frees the remaining 100 base pairs for unstacking.
