Fig. 2: HDAC activation by SIN3B.
From: Mechanism of assembly, activation and lysine selection by the SIN3B histone deacetylase complex
a–c Interactions between SIN3B and HDAC. SIN3Bcore cryo-EM density map at 2.8 Å resolution is shown for relevant sidechains and water molecules. Colour scheme for SIN3B subunits as in Fig. 1. a Close-up view on the interaction between the SIN3B middle domain (SIN3BMD) and the HDAC second calcium ion (Ca2) binding site is shown on the left. Overall structure of the SIN3B complex and relation to zoomed view shown in this figure is illustrated on the right. Residues involved in hydrophobic and backbone-mediated interactions are depicted. b, c Close-up view on the interaction between SIN3B HDAC interacting domain (HID) and the HDAC basic patch, which in other class I HDAC complex is involved in activation by Inositol phosphates (InsPs). The electrostatic surface potential (±5.000) is shown on HDAC in (b). SIN3BHID residues involved in interactions with HDAC2 are depicted. Most of these interactions are water mediated. d, e HDAC activity assay performed with either HDAC alone, SIN3B complex and, SIN3B complex point mutants. Data are presented as mean values ± S.D. of independent experiments, n = 4 for (d) and n = 6 for (e). ***p < 0.0005 (one tailed unpaired t-test). In (d) p = 0.181e−05 (WT vs. HDAC2), p = 2.504e−05 (WT + InsP4 vs. HDAC2 + InsP4). In (e) p = 5.837e−05 (WT vs. E456R/D457R/E461R).
