The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage?
A) nuclease, DNA polymerase, DNA ligase
B) telomerase, primase, DNA polymerase
C) telomerase, helicase, single-strand binding protein
D) DNA ligase, replication fork proteins, adenylyl cyclase
E) nuclease, telomerase, primase

Question

Quizplus · Accepted Answer

The loss of an amino group from adenine in DNA results in the formation of hypoxanthine. If not repaired, hypoxanthine would base pair with cytosine instead of adenine in the next round of DNA replication, leading to a mutation. The repair of this type of DNA damage requires a combination of proteins that includes a nuclease to recognize and cut out the damaged DNA strand, DNA polymerase to fill in the gap with the correct nucleotides, and DNA ligase to seal the nick in the sugar-phosphate backbone. Therefore, the best choice is A) nuclease, DNA polymerase, DNA ligase.

The Spontaneous Loss of Amino Groups from Adenine in DNA