DNA-binding mechanism and evolution of replication protein A

Replication Protein A (RPA) is a heterotrimeric single stranded DNA-binding protein with essential roles in DNA replication, recombination and repair. Little is known about the structure of RPA in Archaea, the third domain of life. By using an integrative structural, biochemical and biophysical approach, we extensively characterize RPA from Pyrococcus abyssi in the presence and absence of DNA. The obtained X-ray and cryo-EM structures reveal that the trimerization core and interactions promoting RPA clustering on ssDNA are shared between archaea and eukaryotes. However, we also identified a helical domain named AROD (Acidic Rpa1 OB-binding Domain), and showed that, in Archaea, RPA forms an unanticipated tetrameric supercomplex in the absence of DNA. The four RPA molecules clustered within the tetramer could efficiently coat and protect stretches of ssDNA created by the advancing replisome. Finally, our results provide insights into the evolution of this primordial replication factor in eukaryotes. Here the authors present the structure of Replication Protein A (RPA) in Archaea. The RPA structure from P. abyssi has been determined in presence and absence of DNA, providing insights into the evolution of this replication factor in eukaryotes

Automated summary

Using an integrative approach, the authors characterized the structure of RPA in Archaea, revealing shared features with eukaryotes, as well as the formation of a tetrameric supercomplex in the absence of DNA. This supercomplex provides protection for ssDNA during replication. These findings contribute to our understanding of the evolution of replication factors in eukaryotes.