4TUR

Human DNA polymerase beta inserting dCMPNPP opposite the 5'G of cisplatin crosslinked Gs (Pt-GG2)

Summary for 4TUR

• Entry DOI: 10.2210/pdb4tur/pdb
• Related: 4TUP 4TUQ 4TUS
• Descriptor: DNA polymerase beta, DNA (5'-D(*CP*CP*CP*AP*CP*GP*GP*CP*CP*CP*AP*TP*CP*AP*CP*C)-3'), DNA (5'-D(*GP*GP*TP*GP*AP*TP*GP*GP*GP*C)-3'), ... (9 entities in total)
• Functional Keywords: dna polymerase, transferase, lyase-dna complex, lyase/dna
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 4
• Total formula weight: 47863.77

Authors

Koag, M.C.,Lee, S. (deposition date: 2014-06-24, release date: 2014-10-01, Last modification date: 2024-03-13)

Primary citation

Koag, M.C.,Lai, L.,Lee, S.
Structural Basis for the Inefficient Nucleotide Incorporation Opposite Cisplatin-DNA Lesion by Human DNA Polymerase beta.
J.Biol.Chem., 289:31341-31348, 2014

PubMed Abstract: Human DNA polymerase β (polβ) has been suggested to play a role in cisplatin resistance, especially in polβ-overexpressing cancer cells. Polβ has been shown to accurately albeit slowly bypass the cisplatin-1,2-d(GpG) (Pt-GG) intramolecular cross-link in vitro. Currently, the structural basis for the inefficient Pt-GG bypass mechanism of polβ is unknown. To gain structural insights into the mechanism, we determined two ternary structures of polβ incorporating dCTP opposite the templating Pt-GG lesion in the presence of the active site Mg(2+) or Mn(2+). The Mg(2+)-bound structure shows that the bulky Pt-GG adduct is accommodated in the polβ active site without any steric hindrance. In addition, both guanines of the Pt-GG lesion form Watson-Crick base pairing with the primer terminus dC and the incoming dCTP, providing the structural basis for the accurate bypass of the Pt-GG adduct by polβ. The Mn(2+)-bound structure shows that polβ adopts a catalytically suboptimal semiclosed conformation during the insertion of dCTP opposite the templating Pt-GG, explaining the inefficient replication across the Pt-GG lesion by polβ. Overall, our studies provide the first structural insights into the mechanism of the potential polβ-mediated cisplatin resistance.

PubMed: 25237188
DOI: 10.1074/jbc.M114.605451

Experimental method

X-RAY DIFFRACTION (2.169 Å)