State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, International Associated Laboratory of CNRS-Fudan-HUNAU on Plant Epigenome Research, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, 200438 Shanghai, China.
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, 200438 Shanghai, PR China.
Proc Natl Acad Sci U S A. 2020 Dec 1;117(48):30391-30399. doi: 10.1073/pnas.2011089117. Epub 2020 Nov 16.
Nucleosome Assembly Protein 1 (NAP1) family proteins are evolutionarily conserved histone chaperones that play important roles in diverse biological processes. In this study, we determined the crystal structure of NAP1-Related Protein 1 (NRP1) complexed with H2A-H2B and uncovered a previously unknown interaction mechanism in histone chaperoning. Both in vitro binding and in vivo plant rescue assays proved that interaction mediated by the N-terminal α-helix (αN) domain is essential for NRP1 function. In addition, the C-terminal acidic domain (CTAD) of NRP1 binds to H2A-H2B through a conserved mode similar to other histone chaperones. We further extended previous knowledge of the NAP1-conserved earmuff domain by mapping the amino acids of NRP1 involved in association with H2A-H2B. Finally, we showed that H2A-H2B interactions mediated by αN, earmuff, and CTAD domains are all required for the effective chaperone activity of NRP1. Collectively, our results reveal multiple interaction modes of a NAP1 family histone chaperone and shed light on how histone chaperones shield H2A-H2B from nonspecific interaction with DNA.
核小体组装蛋白 1 (NAP1) 家族蛋白是进化上保守的组蛋白伴侣，在多种生物学过程中发挥重要作用。在这项研究中，我们确定了 NAP1 相关蛋白 1 (NRP1) 与 H2A-H2B 复合物的晶体结构，揭示了组蛋白伴侣中一个以前未知的相互作用机制。体外结合和体内植物拯救实验均证明，由 N 端α螺旋（αN）结构域介导的相互作用对于 NRP1 的功能至关重要。此外，NRP1 的 C 端酸性结构域（CTAD）通过与其他组蛋白伴侣相似的保守模式与 H2A-H2B 结合。我们通过映射与 H2A-H2B 结合相关的 NRP1 氨基酸，进一步扩展了 NAP1 保守的耳罩结构域的先前知识。最后，我们表明，由αN、耳罩和 CTAD 结构域介导的 H2A-H2B 相互作用均是 NRP1 有效伴侣活性所必需的。总之，我们的研究结果揭示了 NAP1 家族组蛋白伴侣的多种相互作用模式，并阐明了组蛋白伴侣如何保护 H2A-H2B 免受与 DNA 的非特异性相互作用。
