Question

Why reverse transcriptase enzymes are having comparatively high error rates than other polymerases?

(a) Because they are not having 3’-5’ proofreading exonucleolytic activity

(b) Because they are not having 5’-3’ proofreading exonucleolytic activity

(c) Because they are having slow rates of exonucleolytic activity

(d) It is difficult to synthesize DNA from RNA

This question was addressed to me in exam.

My question is from Polymerases topic in portion Basics of Genetic Engineering of Genetic Engineering

Answer 1

Right choice is (a) Because they are not having 3’-5’ proofreading exonucleolytic activity

Easy explanation: Reverse transcriptase enzymes are not having proof reading exonuclease activity in 3’-5’ direction. Hence, when the synthesis is done in 5’-3’ direction it is not checked in the 3’-5’ direction and thus the errors inculcated won’t be removed.