RecF

RecF is a bacterial protein encoded by the recF gene and a core component of the RecFOR pathway, which participates in DNA repair by homologous recombination. The pathway promotes the loading of the RecA recombinase onto single-stranded DNA at gaps or stalled replication forks that are coated with single-stranded binding protein (SSB), facilitating repair and restart of DNA synthesis.

RecF functions as an ATP-binding protein with DNA binding activity. In concert with RecO and RecR, RecF forms the RecFOR complex that recognizes SSB-coated DNA ends and promotes the formation of RecA filaments on the exposed single-stranded DNA. This activity aids strand exchange and homologous pairing, enabling error-free repair of DNA lesions and gaps that arise during replication or following damage.

In Escherichia coli and many other bacteria, RecF is implicated in post-replication repair and the processing of DNA gaps, especially at stalled replication forks. By assisting RecA loading, RecF helps to initiate homologous recombination-based repair, contributing to genome stability after exposure to DNA damaging agents such as ultraviolet light or chemical mutagens.

Genetically, loss of RecF function leads to increased sensitivity to DNA damage, reduced recombination efficiency, and defects in RecA filament formation on SSB-coated DNA. RecF typically acts alongside RecO and RecR, and its activity is studied in the broader context of the RecFOR pathway, which operates in parallel to other repair systems such as RecBCD/ AddAB in different bacterial species.

RecF is widely distributed among bacteria, often co-occurring with recO and recR and sometimes organized in operons with these genes. It is a key, though not universally conserved, element of bacterial DNA repair and genome maintenance. See also RecA, RecO, RecR, RecFOR.