磷酸化鱼精蛋白。II. 与DNA形成的复合物的圆二色性，对离子强度的依赖性。
Phosphorylated protamines. II. Circular dichroism of complexes with DNA, dependency on ionic strength.
作者信息
Willmitzer L, Bode J, Wagner K G
出版信息
Nucleic Acids Res. 1977 Jan;4(1):163-76. doi: 10.1093/nar/4.1.163.
The influence of protamine phosphorylation upon the conformation of nucleoprotamine complexes was studied at different ionic strengths using circular dichroism. The sharp onset of CD spectral changes upon decreasing the NaC1 concentrationwas correlated with the beginning of complex formation and can be used to determine apparent binding affinities in terms of a critical ionic strength. It is show that phosphorylation strongly reduces the binding strength of protamines towards DNA. Directly mixed and reconstituted complexes reveal differences in their CD spectra, which decrease with increasing ionic strength. Spectra of complexes between threefold phosphorylated clupeine Z and DNA obtained by reconstitution or direct mixing at higher ionic strength resemble the phi-type spectra of DNA and are unique for the phosphorylated species. The implications of protamine phosphorylation for chromatin or DNA condensation havebeen discussed.
利用圆二色性研究了在不同离子强度下鱼精蛋白磷酸化对核鱼精蛋白复合物构象的影响。随着氯化钠浓度降低，圆二色光谱变化的急剧起始与复合物形成的开始相关，并且可用于根据临界离子强度确定表观结合亲和力。结果表明，磷酸化强烈降低了鱼精蛋白与DNA的结合强度。直接混合和重构的复合物在其圆二色光谱上显示出差异，这些差异随着离子强度的增加而减小。通过在较高离子强度下重构或直接混合获得的三倍磷酸化鲱精蛋白Z与DNA之间的复合物光谱类似于DNA的φ型光谱，并且对于磷酸化物种是独特的。已经讨论了鱼精蛋白磷酸化对染色质或DNA凝聚的影响。
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