Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chromatin remodeling complex ACF helps establish the appropriate nucleosome spacing for generating repressed chromatin states. ACF activity is stimulated by two defining features of the nucleosomal substrate: a basic patch on the histone H4 N-terminal tail and the specific length of flanking DNA. However, the mechanisms by which these two substrate cues function in the ACF remodeling reaction is not well understood. Using electron paramagnetic resonance spectroscopy with spin-labeled ATP analogs to probe the structure of the ATP active site under physiological solution conditions, we identify a closed state of the ATP-binding pocket that correlates with ATPase activity. We find that the H4 tail promotes pocket closure. We further show that ATPase stimulation by the H4 tail does not require a specific structure connecting the H4 tail and the globular domain. In the case of many DNA helicases, closure of the ATP-binding pocket is regulated by specific DNA substrates. Pocket closure by the H4 tail may analogously provide a mechanism to directly couple substrate recognition to activity. Surprisingly, the flanking DNA, which also stimulates ATP hydrolysis, does not promote pocket closure, suggesting that the H4 tail and flanking DNA may be recognized in different reaction steps.
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PMID:The histone H4 tail regulates the conformation of the ATP-binding pocket in the SNF2h chromatin remodeling enzyme. 2460 92

Although mutations or deletions of chromodomain helicase DNA-binding protein 5 (CHD5) have been linked to cancer and implicate CHD5 in tumor suppression, the ATP-dependent activity of CHD5 is currently unknown. In this study, we discovered that CHD5 is a chromatin remodeling factor with a unique enzymatic activity. CHD5 can expose nucleosomal DNA at one or two discrete positions in the nucleosome. The exposure of the nucleosomal DNA by CHD5 is dependent on ATP hydrolysis, but continued ATP hydrolysis is not required to maintain the nucleosomes in their remodeled state. The activity of CHD5 is distinct from other related chromatin remodeling ATPases, such as ACF and BRG1, and does not lead to complete disruption or destabilization of the nucleosome. Rather, CHD5 likely initiates remodeling in a manner similar to that of other remodeling factors but does not significantly reposition the nucleosome. While the related factor CHD4 shows strong ATPase activity, it does not unwrap nucleosomes as efficiently as CHD5. Our findings add to the growing evidence that chromatin remodeling ATPases have diverse roles in modulating chromatin structure.
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PMID:The tumor suppressor chromodomain helicase DNA-binding protein 5 (CHD5) remodels nucleosomes by unwrapping. 2492 45

Chromatin remodeling complexes utilize the energy of ATP hydrolysis to change the packing state of chromatin, e.g. by catalysing the sliding of nucleosomes along DNA. Here we present simple models to describe experimental data of changes in DNA accessibility along a synthetic, repetitive array of nucleosomes during remodeling by the ACF enzyme or its isolated ATPase subunit, ISWI. We find substantial qualitative differences between the remodeling activities of ISWI and ACF. To understand better the observed behavior for the ACF remodeler, we study more microscopic models of nucleosomal arrays.
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PMID:Computational study of remodeling in a nucleosomal array. 2624 2

BAZ1A, a non-catalytic subunit of the chromatin remodeler complexes ACF and CHRAC, is thought to modulate the ATPase's activity of the complexes and participate in gene transcription, DNA damage checkpoint and double-strand break repair. Recently, the essential role of BAZ1A in mouse male fertility has also been reported. BAZ1A contains one C-terminal bromodomain, which specifically recognizes acetylation of lysine. Here, we report the backbone and side chain (1)H, (13)C and (15)N resonance assignment of the mouse BAZ1A-bromodomain, as a basis for further functional studies and structure determination.
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PMID:Backbone and side-chain NMR assignments for the bromodomain of mouse BAZ1A (ACF1). 2654 24


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