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The phosphorylation domain of the 32-kDa subunit of replication protein A (RPA) modulates RPA-DNA interactions. Evidence for an intersubunit interaction
Journal article   Open access   Peer reviewed

The phosphorylation domain of the 32-kDa subunit of replication protein A (RPA) modulates RPA-DNA interactions. Evidence for an intersubunit interaction

Sara K Binz, Ye Lao, David F Lowry and Marc S Wold
The Journal of biological chemistry, Vol.278(37), pp.35584-35591
09/12/2003
DOI: 10.1074/jbc.M305388200
PMID: 12819197
url
https://doi.org/10.1074/jbc.M305388200View
Published (Version of record) Open Access

Abstract

Replication protein A (RPA) is a heterotrimeric (subunits of 70, 32, and 14 kDa) single-stranded DNA-binding protein that is required for DNA replication, recombination, and repair. The 40-residue N-terminal domain of the 32-kDa subunit of RPA (RPA32) becomes phosphorylated during S-phase and after DNA damage. Recently it has been shown that phosphorylation or the addition of negative charges to this N-terminal phosphorylation domain modulates RPA-protein interactions and increases cell sensitivity to DNA damage. We found that addition of multiple negative charges to the N-terminal phosphorylation domain also caused a significant decrease in the ability of a mutant form of RPA to destabilize double-stranded (ds) DNA. Kinetic studies suggested that the addition of negative charges to the N-terminal phosphorylation domain caused defects in both complex formation (nucleation) and subsequent destabilization of dsDNA by RPA. We conclude that the N-terminal phosphorylation domain modulates RPA interactions with dsDNA. Similar changes in DNA interactions were observed with a mutant form of RPA in which the N-terminal domain of the 70-kDa subunit was deleted. This suggested a functional link between the N-terminal domains of the 70- and 32-kDa subunits of RPA. NMR experiments provided evidence for a direct interaction between the N-terminal domain of the 70-kDa subunit and the negatively charged N-terminal phosphorylation domain of RPA32. These findings suggest that phosphorylation causes a conformational change in the RPA complex that regulates RPA function.
Recombinant Proteins - metabolism Sequence Deletion Phosphorylation Molecular Weight Mutagenesis, Site-Directed Protein Structure, Secondary DNA, Single-Stranded - metabolism Models, Molecular DNA Replication DNA-Binding Proteins - chemistry Protein Subunits - metabolism DNA-Binding Proteins - metabolism Peptide Fragments - chemistry Animals Protein Conformation DNA Damage Replication Protein A

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