Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Nature. 2010 Sep 30;467(7315):562-6. doi: 10.1038/nature09321. Epub 2010 Aug 25.
The small GTPase Ran enzyme regulates critical eukaryotic cellular functions including nuclear transport and mitosis through the creation of a RanGTP gradient around the chromosomes. This concentration gradient is created by the chromatin-bound RCC1 (regulator of chromosome condensation) protein, which recruits Ran to nucleosomes and activates Ran's nucleotide exchange activity. Although RCC1 has been shown to bind directly with the nucleosome, the molecular details of this interaction were not known. Here we determine the crystal structure of a complex of Drosophila RCC1 and the nucleosome core particle at 2.9 Å resolution, providing an atomic view of how a chromatin protein interacts with the histone and DNA components of the nucleosome. Our structure also suggests that the Widom 601 DNA positioning sequence present in the nucleosomes forms a 145-base-pair nucleosome core particle, not the expected canonical 147-base-pair particle.
小分子 GTP 酶 Ran 酶通过在染色体周围创建 RanGTP 梯度来调节关键的真核细胞功能，包括核运输和有丝分裂。这种浓度梯度是由染色质结合的 RCC1（染色体凝聚调节剂）蛋白创建的，该蛋白将 Ran 招募到核小体上并激活 Ran 的核苷酸交换活性。尽管已经表明 RCC1 可以直接与核小体结合，但这种相互作用的分子细节尚不清楚。在这里，我们确定了果蝇 RCC1 和核小体核心颗粒的复合物的晶体结构，分辨率为 2.9Å，提供了一个原子视图，展示了一个染色质蛋白如何与核小体的组蛋白和 DNA 成分相互作用。我们的结构还表明，存在于核小体中的 Widom 601 DNA 定位序列形成了 145 碱基对的核小体核心颗粒，而不是预期的典型 147 碱基对颗粒。
