9B23
Cryo-EM structure of Nap1 core
Summary for 9B23
| Entry DOI | 10.2210/pdb9b23/pdb |
| EMDB information | 44095 |
| Descriptor | NAP1 isoform 1 (1 entity in total) |
| Functional Keywords | histone, chaperone |
| Biological source | Saccharomyces cerevisiae (brewer's yeast) |
| Total number of polymer chains | 2 |
| Total formula weight | 72364.71 |
| Authors | Jiou, J.,Fung, H.Y.J.,Chook, Y.M. (deposition date: 2024-03-14, release date: 2024-11-27, Last modification date: 2024-12-11) |
| Primary citation | Fung, H.Y.J.,Jiou, J.,Niesman, A.B.,Bernardes, N.E.,Chook, Y.M. Nap1 and Kap114 co-chaperone H2A-H2B and facilitate targeted histone release in the nucleus. J.Cell Biol., 224:-, 2025 Cited by PubMed Abstract: Core histones, synthesized and processed in the cytoplasm, must be chaperoned as they are transported into the nucleus for nucleosome assembly. The importin Kap114 transports H2A-H2B into the yeast nucleus, where RanGTP facilitates histone release. Kap114 and H2A-H2B also bind the histone chaperone Nap1, but how Nap1 and Kap114 cooperate in transport and nucleosome assembly remains unclear. Here, biochemical and structural analyses show that Kap114, H2A-H2B, and a Nap1 dimer (Nap12) associate in the absence and presence of RanGTP to form equimolar complexes. A previous study had shown that RanGTP reduces Kap114's ability to chaperone H2A-H2B, but a new cryo-EM structure of the Nap12•H2A-H2B•Kap114•RanGTP complex explains how both Kap114 and Nap12 interact with H2A-H2B, restoring its chaperoning within the assembly while effectively depositing it into nucleosomes. Together, our results suggest that Kap114 and Nap12 provide a sheltered path that facilitates the transfer of H2A-H2B from Kap114 to Nap12, ultimately directing its specific deposition into nucleosomes. PubMed: 39601790DOI: 10.1083/jcb.202408193 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.2 Å) |
Structure validation
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