The function of Deinococcus Radiodurans SSB protein in RecA‐mediated DNA strand exchange

Abstract

Deinococcus Radiodurans (Dr or D. Radiodurans) is a bacterium with an extraordinary resistance to radiation. Strand exchange promoted by the RecA protein is an important process in homologous recombination, which is essential for maintenance of accurate DNA replication. Along with RecA, the single strand DNA binding protein (SSB) is critical to DNA replication, recombination, and repair in all bacteria including Deinococcus Radiodurans. in Deinococcus Radiodurans, SSB is absolutely required for RecA‐mediated DNA strand exchange. We present results indicating that the primary function of DrSSB is to sequester the displaced strand during DNA strand exchange. Furthermore, DrRecA pre‐incubated with ssDNA appears not to work efficiently in the strand exchange reaction, supporting the inverse DNA strand exchange pathway. Further experiment on inverse DNA strand exchange must be done to establish the role of DrSSB and the correct strand exchange model in D. Radiodurans.