The T4 Gp59 protein plays critical roles in the assembly of the phage replisome and its coordination with homologous recombination (1, 2). Gp59 is a versatile mediator protein that loads the replicative DNA helicase, Gp41, onto replication forks and recombination intermediates that are generated during different stages of the T4 infection cycle in its host organism, Escherichia coli. In addition to helicase loading, Gp59 has been shown to perform a second function: polymerase blocking (3-5). Gp59 inhibits the DNA synthesis and exonuclease activities of the phage polymerase, Gp43, until the replisome is fully assembled (3).
The physical purity of this enzyme is ≥98% as assessed by SDS-PAGE with Coomassie® blue staining (Fig. 1).