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-Structure paper
Title | Structural basis of nucleosomal H4K20 methylation by methyltransferase SET8. |
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Journal, issue, pages | FASEB J, Vol. 36, Issue 6, Page e22338, Year 2022 |
Publish date | May 11, 2022 |
![]() | Liuxin Shi / Li Huang / Haizhen Long / Aoqun Song / Zheng Zhou / ![]() |
PubMed Abstract | Histone H4 lysine 20 monomethylation (H4K20me1) plays a crucial role in multiple processes including DNA damage repair, DNA replication, and cell cycle control. Histone methyltransferase SET8 ...Histone H4 lysine 20 monomethylation (H4K20me1) plays a crucial role in multiple processes including DNA damage repair, DNA replication, and cell cycle control. Histone methyltransferase SET8 (previously named PR-Set7/KMT5A) mediates the chromatin deposition of H4K20me1, but how SET8 recognizes and modifies H4 in the context of the nucleosome is not fully understood. Here, we developed a simple chemical modification approach for H4K20 substitution by using the lysine analog S-ethyl-L-cysteine (Ecx). Substitution of H4K20 with H4Ecx20 improves the stability of the SET8-nucleosome complex, allowing us to determine the cryo-EM structure at 3.2 Å resolution. Structural analyses show that SET8 directly interacts with the H4 tail and the H2A-H2B acidic patch to ensure nucleosome binding. SET8 residues R339, K341, K351 make contact with nucleosomal DNA at the super helical location 2 (SHL2). Substitution of SET8 DNA-binding residues with alanines decreases the SET8-nucleosome interaction and impairs the methyltransferase activity. Disrupting the binding between SET8 R192 and H2A-H2B acidic patch decreases the cellular level of H4K20me1. Together, these results reveal a near-atomic resolution structure of SET8-bound nucleosome and provide insights into the SET8-mediated H4K20 recognition and modification. The lysine-to-Ecx substitution approach can be applied to the study of other methyltransferases. |
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Methods | EM (single particle) |
Resolution | 3.2 Å |
Structure data | EMDB-33385, PDB-7xpx: |
Chemicals | ![]() ChemComp-SAM: |
Source |
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![]() | NUCLEAR PROTEIN/DNA / Methyltransferase / Nucleosome / NUCLEAR PROTEIN-DNA COMPLEX |