9GFQ

Structure of PRD1 SSB P12

Summary for 9GFQ

• Entry DOI: 10.2210/pdb9gfq/pdb
• Descriptor: Single-stranded DNA-binding protein (2 entities in total)
• Functional Keywords: ssb, prd1, protein-primed, dna-binding, dna binding protein
• Biological source: Enterobacteria phage PRD1
• Total number of polymer chains: 1
• Total formula weight: 16671.01

Authors

Traeger, L.K.,Huguenin-Dezot, N. (deposition date: 2024-08-12, release date: 2025-04-09, Last modification date: 2025-04-23)

Primary citation

Trager, L.K.,Degen, M.,Pereira, J.,Durairaj, J.,Teixeira, R.D.,Hiller, S.,Huguenin-Dezot, N.
Structural basis for cooperative ssDNA binding by bacteriophage protein filament P12.
Nucleic Acids Res., 53:-, 2025

PubMed Abstract: Protein-primed DNA replication is a unique mechanism, bioorthogonal to other known DNA replication modes. It relies on specialised single-stranded DNA (ssDNA)-binding proteins (SSBs) to stabilise ssDNA intermediates by unknown mechanisms. Here, we present the structural and biochemical characterisation of P12, an SSB from bacteriophage PRD1. High-resolution cryo-electron microscopy reveals that P12 forms a unique, cooperative filament along ssDNA. Each protomer binds the phosphate backbone of 6 nucleotides in a sequence-independent manner, protecting ssDNA from nuclease degradation. Filament formation is driven by an intrinsically disordered C-terminal tail, facilitating cooperative binding. We identify residues essential for ssDNA interaction and link the ssDNA-binding ability of P12 to toxicity in host cells. Bioinformatic analyses place the P12 fold as a distinct branch within the OB-like fold family. This work offers new insights into protein-primed DNA replication and lays a foundation for biotechnological applications.

PubMed: 40052821
DOI: 10.1093/nar/gkaf132

Experimental method

X-RAY DIFFRACTION (1.7 Å)