Replication protein a (RPA) binding to duplex cisplatin-damaged DNA is mediated through the generation of single-stranded DNA

Steve M. Patrick, John J. Turchi

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82 Scopus citations


Replication protein A (RPA) is a heterotrimeric protein composed of 70- , 34-, and 14-kDa subunits that has been shown to be required for DNA replication, repair, and homologous recombination. We have previously shown preferential binding of recombinant human RPA (rhRPA) to duplex cisplatin- damaged DNA compared with the control undamaged DNA (Patrick, S. M., and Turchi, J. J. (1998) Biochemistry 37, 8808-8815). Here we assess the binding of rhRPA to DNA containing site-specific cisplatin-DNA adducts, rhRPA is shown to bind 1.5-2-fold better to a duplex 30-base pair substrate containing a single 1,3d(GpXpG) compared with a 1,2d(GpG) cisplatin-DNA intrastrand adduct, consistent with the difference in thermal stability of DNA containing each adduct. Consistent with these data, a 21-base pair DNA substrate containing a centrally located single interstrand cisplatin cross-link resulted in less binding than to the undamaged control DNA. A series of experiments measuring rhRPA binding and concurrent DNA denaturation revealed that rhRPA binds duplex cisplatin-damaged DNA via the generation of single- stranded DNA. Single-strand DNA binding experiments show that rhRPA binds 3- 4-fold better to an undamaged 24-base DNA compared with the same substrate containing a single 1,2d(GpG) cisplatin-DNA adduct. These data are consistent with a low affinity interaction of rhRPA with duplex-damaged DNA followed by the generation of single-stranded DNA and then high affinity binding to the undamaged DNA strand.

Original languageEnglish (US)
Pages (from-to)14972-14978
Number of pages7
JournalJournal of Biological Chemistry
Issue number21
StatePublished - May 21 1999

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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