Giartosio A, Ferraro A, Altieri F, Eufemi M, Turano C
Department of Biochemical Sciences, University of Rome La Sapienza, Italy.
Physiol Chem Phys Med NMR. 1988;20(1):55-60.
Microcalorimetric titrations of whole chromatin and histones with sodium dodecylsulfate were performed at pH 7 and 25 degrees C. Enthalpy variations at low detergent concentration (less than 0.02%) are much more negative for histones than for chromatin. At 0.065% sodium dodecylsulfate the difference between the two curves becomes constant and, after correction for monomerization effects, amounts to +130 kcal/mol of nucleosomal unit. Core particles show heat effects similar to those of histones. These findings suggest that the chromatin structure is not stabilized exclusively by electrostatic interactions and that hydrogen bonds responsible for the additional stability may be contributed by non histone chromatin proteins.
在pH 7和25摄氏度条件下，用十二烷基硫酸钠对全染色质和组蛋白进行微量热滴定。在低去污剂浓度（小于0.02%）时，组蛋白的焓变比染色质的焓变更负。在0.065%的十二烷基硫酸钠时，两条曲线之间的差异变得恒定，在对单体化效应进行校正后，相当于每个核小体单位+130千卡/摩尔。核心颗粒显示出与组蛋白相似的热效应。这些发现表明，染色质结构并非仅由静电相互作用稳定，负责额外稳定性的氢键可能由非组蛋白染色质蛋白贡献。
