Comparing SSB-PriA Functional and Physical Interactions in Gram-Positive and -Negative Bacteria.

Single-stranded DNA (ssDNA)-binding protein (SSB) is essential for DNA metabolic processes. SSB also binds to many DNA-binding proteins that constitute the SSB interactome. The mechanism through which PriA helicase, an initiator protein in the DNA replication restart process, is stimulated by SSB in Escherichia coli (EcSSB) has been established. However, some Gram-positive bacterial SSBs such as Bacillus subtilis SsbA (a counterpart of EcSSB), Staphylococcus aureus SsbA, SsbB, and SsbC do not activate PriA helicase. Here, we describe some of the methods used in our laboratory to compare SSB-PriA functional and physical interactions in Gram-positive and -negative bacteria.