4qen | pdb_00004qen
crystal structure of KRYPTONITE in complex with mCHH DNA and SAH
Structural highlights
FunctionSUVH4_ARATH Histone methyltransferase. Methylates 'Lys-9' of histone H3. H3 'Lys-9' methylation represents a specific tag for epigenetic transcriptional repression. The silencing mechanism via DNA CpNpG methylation requires the targeting of chromomethylase CMT3 to methylated histones, probably through an interaction with an HP1-like adapter. By its function, KYP is directly required for the maintenance of the DNA CpNpG and asymmetric methylation. Involved in the silencing of transposable elements.[1] [2] [3] [4] [5] Publication Abstract from PubMedIn Arabidopsis, CHG DNA methylation is controlled by the H3K9 methylation mark through a self-reinforcing loop between DNA methyltransferase CHROMOMETHYLASE3 (CMT3) and H3K9 histone methyltransferase KRYPTONITE/SUVH4 (KYP). We report on the structure of KYP in complex with methylated DNA, substrate H3 peptide, and cofactor SAH, thereby defining the spatial positioning of the SRA domain relative to the SET domain. The methylated DNA is bound by the SRA domain with the 5mC flipped out of the DNA, while the H3(1-15) peptide substrate binds between the SET and post-SET domains, with the epsilon-ammonium of K9 positioned adjacent to bound SAH. These structural insights, complemented by functional data on key mutants of residues lining the 5mC and H3K9-binding pockets within KYP, establish how methylated DNA recruits KYP to the histone substrate. Together, the structures of KYP and previously reported CMT3 complexes provide insights into molecular mechanisms linking DNA and histone methylation. Mechanism of DNA Methylation-Directed Histone Methylation by KRYPTONITE.,Du J, Johnson LM, Groth M, Feng S, Hale CJ, Li S, Vashisht AA, Gallego-Bartolome J, Wohlschlegel JA, Patel DJ, Jacobsen SE Mol Cell. 2014 Jul 9. pii: S1097-2765(14)00491-2. doi:, 10.1016/j.molcel.2014.06.009. PMID:25018018[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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