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8fjn

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Crystal Structure of the Trypanosoma brucei DOT1A histone H3K76 methyltransferase in complex with AdoHcy - C2221 space group

Structural highlights

8fjn is a 1 chain structure with sequence from Trypanosoma brucei brucei. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.1Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

Q581Z0_TRYB2 Histone methyltransferase that specifically trimethylates histone H3 to form H3K79me3. This methylation is required for telomere silencing and for the pachytene checkpoint during the meiotic cell cycle by allowing the recruitment of RAD9 to double strand breaks. Nucleosomes are preferred as substrate compared to free histone.[RuleBase:RU271113]

Publication Abstract from PubMed

In higher eukaryotes, a single DOT1 histone H3 lysine 79 (H3K79) methyltransferase processively produces H3K79me2/me3 through histone H2B mono-ubiquitin interaction, while the kinetoplastid Trypanosoma brucei di-methyltransferase DOT1A and tri-methyltransferase DOT1B efficiently methylate the homologous H3K76 without H2B mono-ubiquitination. Based on structural and biochemical analyses of DOT1A, we identify key residues in the methyltransferase motifs VI and X for efficient ubiquitin-independent H3K76 methylation in kinetoplastids. Substitution of a basic to an acidic residue within motif VI (Gx(6)K) is essential to stabilize the DOT1A enzyme-substrate complex, while substitution of the motif X sequence VYGE by CAKS renders a rigid active-site loop flexible, implying a distinct mechanism of substrate recognition. We further reveal distinct methylation kinetics and substrate preferences of DOT1A (H3K76me0) and DOT1B (DOT1A products H3K76me1/me2) in vitro, determined by a Ser and Ala residue within motif IV, respectively, enabling DOT1A and DOT1B to mediate efficient H3K76 tri-methylation non-processively but cooperatively, and suggesting why kinetoplastids have evolved two DOT1 enzymes.

Two DOT1 enzymes cooperatively mediate efficient ubiquitin-independent histone H3 lysine 76 tri-methylation in kinetoplastids.,Frisbie VS, Hashimoto H, Xie Y, De Luna Vitorino FN, Baeza J, Nguyen T, Yuan Z, Kiselar J, Garcia BA, Debler EW Nat Commun. 2024 Mar 19;15(1):2467. doi: 10.1038/s41467-024-46637-6. PMID:38503750^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Frisbie VS, Hashimoto H, Xie Y, De Luna Vitorino FN, Baeza J, Nguyen T, Yuan Z, Kiselar J, Garcia BA, Debler EW. Two DOT1 enzymes cooperatively mediate efficient ubiquitin-independent histone H3 lysine 76 tri-methylation in kinetoplastids. Nat Commun. 2024 Mar 19;15(1):2467. PMID:38503750 doi:10.1038/s41467-024-46637-6