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-Structure paper
タイトル | Structure of IMPORTIN-4 bound to the H3-H4-ASF1 histone-histone chaperone complex. |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 119, Issue 38, Page e2207177119, Year 2022 |
掲載日 | 2022年9月20日 |
著者 | Natália Elisa Bernardes / Ho Yee Joyce Fung / Yang Li / Zhe Chen / Yuh Min Chook / |
PubMed 要旨 | IMPORTIN-4, the primary nuclear import receptor of core histones H3 and H4, binds the H3-H4 dimer and histone chaperone ASF1 prior to nuclear import. However, how H3-H3-ASF1 is recognized for ...IMPORTIN-4, the primary nuclear import receptor of core histones H3 and H4, binds the H3-H4 dimer and histone chaperone ASF1 prior to nuclear import. However, how H3-H3-ASF1 is recognized for transport cannot be explained by available crystal structures of IMPORTIN-4-histone tail peptide complexes. Our 3.5-Å IMPORTIN-4-H3-H4-ASF1 cryoelectron microscopy structure reveals the full nuclear import complex and shows a binding mode different from suggested by previous structures. The N-terminal half of IMPORTIN-4 clamps the globular H3-H4 domain and H3 αN helix, while its C-terminal half binds the H3 N-terminal tail weakly; tail contribution to binding energy is negligible. ASF1 binds H3-H4 without contacting IMPORTIN-4. Together, ASF1 and IMPORTIN-4 shield nucleosomal H3-H4 surfaces to chaperone and import it into the nucleus where RanGTP binds IMPORTIN-4, causing large conformational changes to release H3-H4-ASF1. This work explains how full-length H3-H4 binds IMPORTIN-4 in the cytoplasm and how it is released in the nucleus. |
リンク | Proc Natl Acad Sci U S A / PubMed:36103578 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.45 - 7.1 Å |
構造データ | EMDB-26625, PDB-7unk: EMDB-27780, PDB-8dyo: |
化合物 | ChemComp-MG: ChemComp-GTP: |
由来 |
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キーワード | NUCLEAR PROTEIN / Importin / Nuclear Import / Chaperone / Histones / H3 / H4 / ASF1 / PROTEIN TRANSPORT / Karyopherin / GTPase |