Structure and dynamics of the chromatin remodeler ALC1 bound to a PARylated nucleosome.
The chromatin remodeler ALC1 is recruited to and activated by DNA damage-induced poly(ADP-ribose) (PAR) chains deposited by PARP1/PARP2/HPF1 upon detection of DNA lesions. ALC1 has emerged as a candidate drug target for cancer therapy as its loss confers synthetic lethality in homologous recombination-deficient cells. However, structure-based drug design and molecular analysis of ALC1 have been hindered by the requirement for PARylation and the highly heterogeneous nature of this post-translational modification. Here, we reconstituted an ALC1 and PARylated nucleosome complex modified in vitro using PARP2 and HPF1. This complex was amenable to cryo-EM structure determination without cross-linking, which enabled visualization of several intermediate states of ALC1 from the recognition of the PARylated nucleosome to the tight binding and activation of the remodeler. Functional biochemical assays with PARylated nucleosomes highlight the importance of nucleosomal epitopes for productive remodeling and suggest that ALC1 preferentially slides nucleosomes away from DNA breaks.
['Bacic|Luka|L|0000-0001-6896-3506', 'Gaullier|Guillaume|G|0000-0003-3405-6021', 'Sabantsev|Anton|A|0000-0002-8559-8894', 'Lehmann|Laura C|LC|0000-0003-2518-5606', 'Brackmann|Klaus|K|', 'Dimakou|Despoina|D|0000-0002-1424-5469', 'Halic|Mario|M|0000-0002-0061-7372', 'Hewitt|Graeme|G|', 'Boulton|Simon J|SJ|', 'Deindl|Sebastian|S|0000-0001-6807-8654']
D002352:Carrier Proteins D042002:Chromatin Assembly and Disassembly D020285:Cryoelectron Microscopy D004265:DNA Helicases D004268:DNA-Binding Proteins D006801:Humans D007700:Kinetics D008958:Models, Molecular D009687:Nuclear Proteins D009707:Nucleosomes D000071137:Poly (ADP-Ribose) Polymerase-1 D000074747:Poly ADP Ribosylation D011065:Poly(ADP-ribose) Polymerases D011485:Protein Binding D011487:Protein Conformation D011994:Recombinant Proteins D013329:Structure-Activity Relationship D013379:Substrate Specificity
chromatin remodeling nucleosome PARP1 ALC1/CHD1L chromosomes gene expression human molecular biophysics poly(ADP-ribose)ylation structural biology