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)topoisomerase,primase,DNA polymerase
C)topoisomerase,helicase,single-strand binding protein
D)DNA ligase,replication fork proteins,adenylyl cyclase

Question

Quizplus · Accepted Answer

The loss of an amino group from adenine in DNA creates a hypoxanthine base, which is uncommon in DNA and opposite thymine. This is an example of spontaneous damage to DNA. The repair of this damage would require a repair pathway called base excision repair, which involves the removal of the damaged base, followed by the insertion of a new nucleotide by DNA polymerase, and then sealing of the nick with DNA ligase. Therefore, the combination of proteins required for this repair would be nuclease, DNA polymerase, and DNA ligase, which are all involved in base excision repair. Choice A is the only option that includes all three of these proteins. The other options do not include nuclease or DNA ligase, and their protein combinations are not suited to repairing this specific type of DNA damage.

The Spontaneous Loss of Amino Groups from Adenine in DNA