ジャーナル: Sci Rep / 年: 2015 タイトル: Molecular architecture of the Ub-PCNA/Pol η complex bound to DNA. 著者: Wilson C Y Lau / Yinyin Li / Qinfen Zhang / Michael S Y Huen / 要旨: 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 ...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.
名称: Ub-PCNA/Pol eta/DNA / タイプ: COMPLEX 詳細: Monomeric catalytic core of Pol eta binds to one homotrimeric Ub-PCNA 別称: Monoubiquitinated PCNA
分子量
値: 0.2 MDa / 実験値: YES
緩衝液
pH: 8 / 詳細: 50mM Tris-HCl, 5mM MgCl2
試料
包埋: NO / シャドウイング: NO / 染色: YES / 凍結: NO 詳細: 50mM Tris-HCl, 5mM MgCl2 (Stain Details Grids with adsorbed protein floated on two 20 ul drops of 2% w/v uranyl acetate solution for 30 seconds)