Molecular architecture of the Ub-PCNA/Pol η complex bound to DNA.
Translesion synthesis (TLS) is the mechanism by which DNA polymerases replicate through unrepaired DNA lesions. TLS is activated by monoubiquitination of the homotrimeric proliferating cell nuclear antigen (PCNA) at lysine-164, followed by the switch from replicative to specialized polymerases at DNA damage sites. Pol η belongs to the Y-Family of specialized polymerases that can efficiently bypass UV-induced lesions. Like other members of the Y-Family polymerases, its recruitment to the damaged sites is mediated by the interaction with monoubiquitinated PCNA (Ub-PCNA) via its ubiquitin-binding domain and non-canonical PCNA-interacting motif in the C-terminal region. The structural determinants underlying the direct recognition of Ub-PCNA by Pol η, or Y-Family polymerases in general, remain largely unknown. Here we report a structure of the Ub-PCNA/Pol η complex bound to DNA determined by single-particle electron microscopy (EM). The overall obtained structure resembles that of the editing PCNA/PolB complex. Analysis of the map revealed the conformation of ubiquitin that binds the C-terminal domain of Pol η. Our present study suggests that the Ub-PCNA/Pol η interaction requires the formation of a structured binding interface, which is dictated by the inherent flexibility of Ub-PCNA.
School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China.|State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China.
Wilson C Y
WC
Lau
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
Yinyin
Y
Li
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
Qinfen
Q
Zhang
School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China.|State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China.
Michael S Y
MS
Huen
D001360:Avidin / Q000737:chemistry; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D006801:Humans; D008854:Microscopy, Electron; D056004:Molecular Dynamics Simulation; D017354:Point Mutation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D025801:Ubiquitin / Q000235:genetics / Q000378:metabolism*; D000099270:Y-Family DNA Polymerases
D001360:Avidin; D004247:DNA; D004259:DNA-Directed DNA Polymerase; D018809:Proliferating Cell Nuclear Antigen; D025801:Ubiquitin; C093483:neutravidin; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases