2fsa
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Crystal structure of PHD finger-linker-bromodomain fragment of human BPTF in the H3(1-15)K4ME2 bound state
OverviewOverview
Mono-, di- and trimethylated states of particular histone lysine residues, are selectively found in different regions of chromatin, thereby implying, specialized biological functions for these marks ranging from, heterochromatin formation to X-chromosome inactivation and transcriptional, regulation. A major challenge in chromatin biology has centred on efforts, to define the connection between specific methylation states and distinct, biological read-outs impacting on function. For example, histone H3, trimethylated at lysine 4 (H3K4me3) is associated with transcription start, sites of active genes, but the molecular 'effectors' involved in specific, recognition of H3K4me3 tails remain poorly understood. Here we demonstrate, the molecular basis for specific recognition of H3(1-15)K4me3 (residues, 1-15 of histone H3 trimethylated at K4) by a plant homeodomain (PHD), finger of human BPTF (bromodomain and PHD domain transcription factor), the largest subunit of the ATP-dependent chromatin-remodelling complex, NURF (nucleosome remodelling factor). We report on crystallographic and, NMR structures of the bromodomain-proximal PHD finger of BPTF in free and, H3(1-15)K4me3-bound states. H3(1-15)K4me3 interacts through anti-parallel, beta-sheet formation on the surface of the PHD finger, with the long side, chains of arginine 2 (R2) and K4me3 fitting snugly in adjacent pre-formed, surface pockets, and bracketing an invariant tryptophan. The observed, stapling role by non-adjacent R2 and K4me3 provides a molecular, explanation for H3K4me3 site specificity. Binding studies establish that, the BPTF PHD finger exhibits a modest preference for K4me3- over, K4me2-containing H3 peptides, and discriminates against monomethylated and, unmodified counterparts. Furthermore, we identified key, specificity-determining residues from binding studies of H3(1-15)K4me3, with PHD finger point mutants. Our findings call attention to the PHD, finger as a previously uncharacterized chromatin-binding module found in a, large number of chromatin-associated proteins.
About this StructureAbout this Structure
2FSA is a Single protein structure of sequence from Homo sapiens with ZN as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Molecular basis for site-specific read-out of histone H3K4me3 by the BPTF PHD finger of NURF., Li H, Ilin S, Wang W, Duncan EM, Wysocka J, Allis CD, Patel DJ, Nature. 2006 Jul 6;442(7098):91-5. Epub 2006 May 21. PMID:16728978
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