Classifying the Functionality of Primosome Protein A in Deinococcus Radiodurans

Deinococcus radiodurans is an extremophile bacterium with the capacity to withstand tremendous DNA damage that causes disruption of replisome complex activity. The efficiency of origin-independent replisome reloading directly correlates to effectiveness of DNA damage coping strategies, and remains largely undefined in D. rad primosome components. Investigation of D. rad PriA as a helicase protein was conducted to determine if PriA could be classified as a fossilized helicase. This project tested the three functions of known helicases by comparing E. coli and D. rad PriA. DNA binding, DNA unwinding, and ATP hydrolysis assays were performed on both proteins separately and results compared. E.coli PriA demonstrated ability to perform all three helicase functions while D.rad PriA only demonstrated ability to bind to DNA. The results supported the hypothesis, thus classifying D.rad PriA as a fossilized helicase. While the PriA protein of D.rad may be structurally similar to PriA proteins in other bacteria, the evolution of the D. rad genome over time has rendered the helicase function of D.rad PriA inoperable.