Experimental Biophysics and Applied Nanoscience, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany.
Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, Barcelona 08028, Spain; Barcelona Institute for Global Health (ISGlobal), Barcelona Center for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, Barcelona 08036, Spain; Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, Barcelona 08028, Spain.
Biochim Biophys Acta Gen Subj. 2017 Nov;1861(11 Pt A):2739-2749. doi: 10.1016/j.bbagen.2017.07.018. Epub 2017 Jul 27.
Despite the profound current knowledge of the architecture and dynamics of nucleosomes, little is known about the structures generated by the interaction of histones with single-stranded DNA (ssDNA), which is widely present during replication and transcription.
Non-denaturing gel electrophoresis, transmission electron microscopy, atomic force microscopy, magnetic tweezers.
Histones have a high affinity for ssDNA in 0.15M NaCl ionic strength, with an apparent binding constant similar to that calculated for their association with double-stranded DNA (dsDNA). The length of DNA (number of nucleotides in ssDNA or base pairs in dsDNA) associated with a fixed core histone mass is the same for both ssDNA and dsDNA. Although histone-ssDNA complexes show a high tendency to aggregate, nucleosome-like structures are formed at physiological salt concentrations. Core histones are able to protect ssDNA from digestion by micrococcal nuclease, and a shortening of ssDNA occurs upon its interaction with histones. The purified (+) strand of a cloned DNA fragment of nucleosomal origin has a higher affinity for histones than the purified complementary (-) strand.
At physiological ionic strength histones have high affinity for ssDNA, possibly associating with it into nucleosome-like structures.
In the cell nucleus histones may spontaneously interact with ssDNA to facilitate their participation in the replication and transcription of chromatin.
尽管目前人们对核小体的结构和动力学有了深刻的认识，但对于组蛋白与单链 DNA（ssDNA）相互作用产生的结构却知之甚少，ssDNA 在复制和转录过程中广泛存在。
非变性凝胶电泳、透射电子显微镜、原子力显微镜、磁镊。
组蛋白在 0.15M NaCl 离子强度下与 ssDNA 具有高亲和力，表观结合常数与它们与双链 DNA（dsDNA）的结合常数相似。与固定核心组蛋白质量相关的 DNA 长度（ssDNA 中的核苷酸数或 dsDNA 中的碱基对数）对于 ssDNA 和 dsDNA 相同。尽管组蛋白-ssDNA 复合物具有强烈的聚集倾向，但在生理盐浓度下会形成核小体样结构。核心组蛋白能够保护 ssDNA 免受微球菌核酸酶的消化，并且在与组蛋白相互作用时 ssDNA 会缩短。源自核小体的克隆 DNA 片段的纯化（+）链比纯化的互补（-）链对组蛋白具有更高的亲和力。
在生理离子强度下，组蛋白与 ssDNA 具有高亲和力，可能与其形成核小体样结构有关。
在细胞核中，组蛋白可能会自发地与 ssDNA 相互作用，从而促进它们参与染色质的复制和转录。
