Chromosomal duplication requires de novo assembly of nucleosomes from newly synthesized histones, and the process involves a dynamic network of interactions between histones and histone chaperones. sNASP and ASF1 are two major histone H3–H4 chaperones found in distinct and common complexes, yet how sNASP binds H3–H4 in the presence and absence of ASF1 remains unclear. Here we show that, in the presence of ASF1, sNASP principally recognizes a partially unfolded Nα region of histone H3, and in the absence of ASF1, an additional sNASP binding site becomes available in the core domain of the H3–H4 complex. Our study also implicates a critical role of the C-terminal tail of H4 in the transfer of H3–H4 between sNASP and ASF1 and the coiled-coil domain of sNASP in nucleosome assembly. These findings provide mechanistic insights into coordinated histone binding and transfer by histone chaperones.

中文翻译：

---

sNASP不同的组蛋白H3-H4结合模式揭示了组蛋白伴侣合作与竞争的基础

染色体复制需要从新合成的组蛋白中重新组装核小体，该过程涉及组蛋白和组蛋白伴侣之间相互作用的动态网络。sNASP 和 ASF1 是在不同且常见的复合物中发现的两种主要组蛋白 H3-H4 伴侣，但在存在和不存在 ASF1 的情况下 sNASP 如何结合 H3-H4 仍不清楚。在这里，我们表明，在 ASF1 存在的情况下，sNASP 主要识别组蛋白 H3 的部分展开的 Nα 区域，在没有 ASF1 的情况下，在 H3-H4 复合物的核心域中可以使用额外的 sNASP 结合位点。我们的研究还暗示了 H4 的 C 末端尾部在 sNASP 和 ASF1 之间的 H3-H4 转移以及核小体组装中 sNASP 的卷曲螺旋结构域中的关键作用。