3iif
From Proteopedia
Crystal structure of the macro domain of human histone macroH2A1.1 in complex with ADP-ribose (form B)
Structural highlights
FunctionH2AY_HUMAN Variant histone H2A which replaces conventional H2A in a subset of nucleosomes where it represses transcription. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Involved in stable X chromosome inactivation. Inhibits the binding of transcription factors and interferes with the activity of remodeling SWI/SNF complexes. Inhibits histone acetylation by EP300 and recruits class I HDACs, which induces a hypoacetylated state of chromatin. In addition, isoform 1, but not isoform 2, binds ADP-ribose and O-acetyl-ADP-ribose, and may be involved in ADP-ribose-mediated chromatin modulation.[1] [2] [3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedPoly-ADP-ribosylation is a post-translational modification catalyzed by PARP enzymes with roles in transcription and chromatin biology. Here we show that distinct macrodomains, including those of histone macroH2A1.1, are recruited to sites of PARP1 activation induced by laser-generated DNA damage. Chemical PARP1 inhibitors, PARP1 knockdown and mutation of ADP-ribose-binding residues in macroH2A1.1 abrogate macrodomain recruitment. Notably, histone macroH2A1.1 senses PARP1 activation, transiently compacts chromatin, reduces the recruitment of DNA damage factor Ku70-Ku80 and alters gamma-H2AX patterns, whereas the splice variant macroH2A1.2, which is deficient in poly-ADP-ribose binding, does not mediate chromatin rearrangements upon PARP1 activation. The structure of the macroH2A1.1 macrodomain in complex with ADP-ribose establishes a poly-ADP-ribose cap-binding function and reveals conformational changes in the macrodomain upon ligand binding. We thus identify macrodomains as modules that directly sense PARP activation in vivo and establish macroH2A histones as dynamic regulators of chromatin plasticity. A macrodomain-containing histone rearranges chromatin upon sensing PARP1 activation.,Timinszky G, Till S, Hassa PO, Hothorn M, Kustatscher G, Nijmeijer B, Colombelli J, Altmeyer M, Stelzer EH, Scheffzek K, Hottiger MO, Ladurner AG Nat Struct Mol Biol. 2009 Sep;16(9):923-9. Epub 2009 Aug 13. PMID:19680243[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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