Identification of the ssDNA-binding protein of bacteriophage T5: Implications for T5 replication

Abstract

In a recent study, we identified and characterized the long-elusive replicative single-stranded DNA-binding protein of bacteriophage T5, which we showed is related to the eukaryotic transcription coactivator PC4. Here, we provide an extended discussion of these data, report several additional observations and consider implications for the recombination-dependent replication mechanism of the T5 genus, which is still poorly understood.

Keywords: 3R; PC4; RDR; SSB; T5; recombination; repair; replication; single-stranded DNA.

Figure 1. Comparison of the core domain of gp32, the SSB of bacteriophage T4 (A, PDB entry 1GPC), to the PC4-like SSB encoded by T5 (B, PDB entry 4BG7). Protein monomers are shown in blue and pink. For the T5 SSB, a tentative model for bound ssDNA strands (in red and green) has been added, based on superposition of the crystal structure of human PC4 bound to an oligonucleotide (PDB code 2C62). The ssDNA backbones are shown as coils, the bases as sticks. For gp32, no comparably detailed ssDNA model is currently available; instead, the location of the ssDNA-binding channel has been indicated. Images were prepared using PyMOL 0.99rc6 (DeLano Scientific).