4ype

ASH1L SET domain H2193F mutant in complex with S-adenosyl methionine (SAM)

spinqualitylabelsall models 4ype, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4ype is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: SAM, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ASH1L_HUMAN Histone methyltransferase specifically methylating 'Lys-36' of histone H3 (H3K36me). Publication Abstract from PubMed ASH1L (absent, small, or homeotic-like 1) is a histone methyltransferase (HMTase) involved in gene activation that is overexpressed in multiple forms of cancer. Previous studies of ASH1L's catalytic SET domain identified an autoinhibitory loop that blocks access of histone substrate to the enzyme active site. Here, we used both nuclear magnetic resonance and X-ray crystallography to identify conformational dynamics in the ASH1L autoinhibitory loop. Using site-directed mutagenesis, we found that point mutations in the autoinhibitory loop that perturb the structure of the SET domain result in decreased enzyme activity, indicating that the autoinhibitory loop is not a simple gate to the active site but is rather a key feature critical to ASH1L function. We also identified a second loop in the SET-I subdomain of ASH1L that experiences conformational dynamics, and we trapped two different conformations of this loop using crystallographic studies. Mutation of the SET-I loop led to a large decrease in ASH1L enzymatic activity in addition to a significant conformational change in the SET-I loop, demonstrating the importance of the structure and dynamics of the SET-I loop to ASH1L function. Furthermore, we found that three C-terminal chromatin-interacting domains greatly enhance ASH1L enzymatic activity and that ASH1L requires native nucleosome substrate for robust activity. Our study illuminates the role of concerted conformational dynamics in ASH1L function and identifies structural features important for ASH1L enzymatic activity. Two Loops Undergoing Concerted Dynamics Regulate the Activity of the ASH1L Histone Methyltransferase.,Rogawski DS, Ndoj J, Cho HJ, Maillard I, Grembecka J, Cierpicki T Biochemistry. 2015 Aug 25. PMID:26292256 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Histone methyltransferase 3D structures

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