Michael L Nosella, Tae Hun Kim, Shuya Kate Huang, Robert W Harkness, Monica Goncalves, Alisia Pan, Maria Tereshchenko, Siavash Vahidi, John L Rubinstein, Hyun O Lee, Julie D Forman-Kay, Lewis E Kay
Nucleosomes, the basic structural units of chromatin, hinder recruitment and activity of various DNA repair proteins, necessitating modifications that enhance DNA accessibility. Poly(ADP-ribosyl)ation (PARylation) of proteins near damage sites is an essential initiation step in several DNA-repair pathways; however, its effects on nucleosome structural dynamics and organization are unclear. Using NMR, cryoelectron microscopy (cryo-EM), and biochemical assays, we show that PARylation enhances motions of the histone H3 tail and DNA, leaving the configuration of the core intact while also stimulating nuclease digestion and ligation of nicked nucleosomal DNA by LIG3...
January 8, 2024: Molecular Cell