Question

Sometimes the amino groups from adenine in dna are lost, resulting in hypoxanthine, an uncommon base, opposite thymine. what combination of proteins could repair such damage?

a. nuclease, dna
b. polymerase, dna ligase
c. nuclease, telomerase, primase
d. dna ligase, replication fork
e. proteins, adenylyl cyclase
f. telomerase, primase, dna polymerase
g. telomerase, helicase, single-strand binding protein

Answer 1

The repair of adenine deamination, where hypoxanthine is incorrectly paired with thymine in DNA, involves nucleotide excision repair using a trio of enzymes: nuclease, DNA polymerase, and DNA ligase.

Step-by-step explanation:

When adenine in DNA deaminates, losing its amino group, it results in the production of hypoxanthine, a rare base that pairs incorrectly with thymine. The DNA repair system needs to recognize and fix this error to prevent mutations from being propagated. The combination of proteins required to repair such damage typically includes a nuclease, which would excise the incorrect base or a section of DNA, DNA polymerase, which would fill in the correct bases by synthesizing new DNA using the undamaged strand as a template, and DNA ligase, which seals the final 'nick' or gap in the DNA backbone to complete the repair. This combination of actions is known as nucleotide excision repair, and is particularly effective against damage such as UV-induced thymine dimers and the deamination of adenine to hypoxanthine.