Question

Which of the molecule in photolyase acts as an electron donor for recovery of the CPD?

(a) NADH

(b) FADH-

(c) MTHF poly Glu

(d) NAD+

The question was posed to me during an interview.

This intriguing question originated from Repair of DNA Damage: NER, Direct Reversal in portion DNA Mutation, DNA Repair, Transposable Elements of Cytogenetics

Answer 1

The correct answer is (b) FADH-

The best I can explain: When the chromophore MTHF poly Glu receives the UV light, it passes the energy on to FADH- which in turn passes the electron to CPD. The electron helps in rearrangement of the bonds in CPD and returns them to the form of two pyrimidine residues.