What is the main function of micrococcal nuclease?

The main function of micrococcal nuclease is to digest DNA or RNA at AT-AU rich regions, which is accurately described in the chosen answer. This enzyme is particularly known for its ability to cleave nucleic acids by recognizing and acting on the structure of the DNA or RNA. Micrococcal nuclease targets the phosphate backbone of nucleic acids, and its activity is enhanced in areas where adenine-thymine (A-T) or adenine-uracil (A-U) base pairs are present due to the weaker hydrogen bonding in these regions compared to guanine-cytosine (G-C) rich areas.

Micrococcal nuclease is commonly used in molecular biology for applications such as chromatin research, where it helps in the digestion of DNA to study the structure and role of chromatin in gene regulation. Its specificity for AT-AU rich regions enables researchers to selectively obtain fragments for various analytical procedures.

The other options do not accurately reflect the enzyme's broad activity. For instance, the enzyme does not exclusively digest double-stranded DNA; it acts on both DNA and RNA. It is also not limited to degrading RNA only, nor does it specifically target pyrimidines, which are merely components of nucle