Question

In bacterial DNA extraction, why is EDTA used despite bacteria protecting their DNA through base modification?

a. EDTA deactivates metal-dependent nucleases, preventing DNA degradation.
b. Bacteria rely on supercoiling and base modification for DNA protection.
c. The cytoplasmic environment makes bacterial DNA susceptible to nucleases.
d. Bacterial DNA is inherently resistant to nucleases, making EDTA unnecessary.

Answer 1

EDTA is used in bacterial DNA extraction to deactivate metal-dependent nucleases that could degrade DNA during the extraction process, even though bacteria have other DNA protective mechanisms.

In bacterial DNA extraction, EDTA is used because it deactivates metal-dependent nucleases, preventing DNA degradation. Despite bacteria having protective mechanisms such as base modification to ward off foreign DNA, the process of DNA extraction puts bacterial DNA at risk of degradation by these nucleases. EDTA chelates divalent metal ions such as Mg2+ and Ca2+, essential cofactors for the function of nucleases. Hence, by using EDTA, the nucleases are inactivated, ensuring the integrity of the bacterial DNA during the extraction process.