Fig. 2: Cryo-EM structure of SIRT7 bound to the H3K36MTU nucleosome.
From: Structural basis of SIRT7 nucleosome engagement and substrate specificity
a Cryo-EM reconstruction showing SIRT7 bound to the nucleosome, with a mechanism-based cross-link to H3K36 (ADPr-MTU: adenosine diphosphate ribose-methylthiourea adduct). See Supplementary Figs. 3‒4 for data processing workflow, resolution, and angular particle distribution. b Model of SIRT7(10-362) bound to the H3K36MTU nucleosome. See Supplementary Fig. 5 for model quality. The gray numbers indicate superhelical locations (SHL) along the nucleosomal DNA. For a detailed view of regions I–III, see e, f. c Cryo-EM density of the ADPr-MTU covalent adduct and fitting of a mechanism-based bicyclic intermediate model. See Supplementary Fig. 6 for LC-MS data. d Detailed interactions of the SIRT7 catalytic domain with the 2nd DNA gyre and the H3 tail. e Detailed interactions with linker DNA, corresponding to frame “I” in Fig. 2b. f SIRT7 domain organization (IDR: intrinsically disordered region) and detailed interactions of the N-terminal (nucleosome binding-) domain with DNA and histones. Panels correspond to frames “II” and “III” in Fig. 2b. g Cryo-EM structure of SIRT6 bound to a nucleosome, highlighting the arginine anchor (R175) interaction with the nucleosome acidic patch (PDB 8G57)52.
