3mwy
From Proteopedia
Crystal structure of the chromodomain-ATPase portion of the yeast Chd1 chromatin remodeler
Structural highlights
FunctionCHD1_YEAST ATP-dependent chromatin-remodeling factor which functions as substrate recognition component of the transcription regulatory histone acetylation (HAT) complexes SAGA and SLIK. It recognizes H3K4me. SAGA is involved in RNA polymerase II-dependent transcriptional regulation of approximately 10% of yeast genes. At the promoters, SAGA is required for recruitment of the basal transcription machinery. It influences RNA polymerase II transcriptional activity through different activities such as TBP interaction (SPT3, SPT8 and SPT20) and promoter selectivity, interaction with transcription activators (GCN5, ADA2, ADA3 and TRA1), and chromatin modification through histone acetylation (GCN5) and deubiquitination (UBP8). SAGA acetylates nucleosomal histone H3 to some extent (to form H3K9ac, H3K14ac, H3K18ac and H3K23ac). SAGA interacts with DNA via upstream activating sequences (UASs). SLIK is proposed to have partly overlapping functions with SAGA. It preferentially acetylates methylated histone H3, at least after activation at the GAL1-10 locus. Acts in opposition to the FACT complex in regulating polymerase II transcription. Also required for efficient transcription by RNA polymerase I, and more specifically the pol I transcription termination step. Regulates negatively DNA replication. Not only involved in transcription-related chromatin-remodeling, but also required to maintain a specific chromatin configuration across the genome.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] 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 PubMedChromatin remodelers are ATP-driven machines that assemble, slide, and remove nucleosomes from DNA, but how the ATPase motors of remodelers are regulated is poorly understood. Here we show that the double chromodomain unit of the Chd1 remodeler blocks DNA binding and activation of the ATPase motor in the absence of nucleosome substrates. The Chd1 crystal structure reveals that an acidic helix joining the chromodomains can pack against a DNA-binding surface of the ATPase motor. Disruption of the chromodomain-ATPase interface prevents discrimination between nucleosomes and naked DNA and reduces the reliance on the histone H4 tail for nucleosome sliding. We propose that the chromodomains allow Chd1 to distinguish between nucleosomes and naked DNA by physically gating access to the ATPase motor, and we hypothesize that related ATPase motors may employ a similar strategy to discriminate among DNA-containing substrates. The chromodomains of the Chd1 chromatin remodeler regulate DNA access to the ATPase motor.,Hauk G, McKnight JN, Nodelman IM, Bowman GD Mol Cell. 2010 Sep 10;39(5):711-23. PMID:20832723[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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