5DGA

CRYSTAL STRUCTURE OF HUMAN DNA POLYMERASE ETA EXTENDING AN 1,N6-ETHENODEOXYADENOSINE : dT PAIR BY INSERTING dTMPNPP OPPOSITE TEMPLATE dA

Summary for 5DGA

• Entry DOI: 10.2210/pdb5dga/pdb
• Related: 5DG7 5DG8 5DG9 5DGB
• Descriptor: DNA polymerase eta, DNA (5'-D(*CP*AP*TP*AP*(EDA)P*TP*GP*AP*CP*GP*CP*T)-3'), DNA (5'-D(*AP*GP*CP*GP*TP*CP*AP*T)-3'), ... (6 entities in total)
• Functional Keywords: dna polymerase, dna enzyme, dna damage, translesion dna synthesis, etheno dna adducts, transferase-dna complex, transferase/dna
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 3
• Total formula weight: 55244.54

Authors

Patra, A.,Egli, M. (deposition date: 2015-08-27, release date: 2016-06-08, Last modification date: 2023-09-27)

Primary citation

Patra, A.,Su, Y.,Zhang, Q.,Johnson, K.M.,Guengerich, F.P.,Egli, M.
Structural and Kinetic Analysis of Miscoding Opposite the DNA Adduct 1,N6-Ethenodeoxyadenosine by Human Translesion DNA Polymerase eta.
J.Biol.Chem., 291:14134-14145, 2016

PubMed Abstract: 1,N(6)-Ethenodeoxyadenosine (1,N(6)-ϵdA) is the major etheno lesion formed in the reaction of DNA with epoxides substituted with good leaving groups (e.g. vinyl chloride epoxide). This lesion is also formed endogenously in DNA from lipid oxidation. Recombinant human DNA polymerase η (hpol η) can replicate oligonucleotide templates containing 1,N(6)-ϵdA. In steady-state kinetic analysis, hpol η preferred to incorporate dATP and dGTP, compared with dTTP. Mass spectral analysis of incorporation products also showed preferred purine (A, G) incorporation and extensive -1 frameshifts, suggesting pairing of the inserted purine and slippage before further replication. Five x-ray crystal structures of hpol η ternary complexes were determined, three at the insertion and two at the extension stage. Two insertion complexes revealed incoming non-hydrolyzable dATP or dGTP analogs not pairing with but instead in a staggered configuration relative to 1,N(6)-ϵdA in the anti conformation, thus opposite the 5'-T in the template, explaining the proclivity for frameshift misincorporation. In another insertion complex, dTTP was positioned opposite 1,N(6)-ϵdA, and the adduct base was in the syn conformation, with formation of two hydrogen bonds. At the extension stage, with either an incorporated dA or dT opposite 1,N(6)-ϵdA and 2'-deoxythymidine-5'-[(α,β)-imido]triphosphate opposite the 5'-A, the 3'-terminal nucleoside of the primer was disordered, consistent with the tendency not to incorporate dTTP opposite 1,N(6)-ϵdA. Collectively, the results show a preference for purine pairing opposite 1,N(6)-ϵdA and for -1 frameshifts.

PubMed: 27226627
DOI: 10.1074/jbc.M116.732487

Experimental method

X-RAY DIFFRACTION (2.3 Å)