The question is attached. This is what I think so far, but would like someone to clear things up. This is one of the discussion questions my professor handed out to help us prepare for a final, so help will be greatly appreciated.
What I think:
Deoxyribonuclease I (DNase I) is an endonuclease that cleaves DNA preferentially at phosphodiester linkages adjacent to a pyrimidine nucleotide, yielding 5'-phosphate-terminated polynucleotides with a free hydroxyl group on position 3', on average producing tetranucleotides. It acts on single-stranded DNA, double-stranded DNA, and chromatin. Micrococcal Nuclease (S7 Nuclease or MNase) is an endo-exonuclease that preferentially digests single-stranded nucleic acids.The rate of cleavage is 30 times greater at the 5' side of A or T than at G or C and results in the production of mononucleotides and oligonucleotides with terminal 3'-phosphates. The enzyme is also active against double-stranded DNA and RNA and all sequences will be ultimately cleaved.
For part A and C of the question, I believe it has to do with the differences in cleaving or restriction sites, but might also be due to DNase I being blocked from activity. If so, I’m not sure what is doing the blocking? Lastly, histone proteins could be another reason with differences in the packaging of nucleosomes. For B, not really sure. Micrococcal nuclease results in more so clear cut bands, rather than degraded DNA with DNase I.
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