Question

Topoisomerase is also an enzyme which is used for carrying out ligation. The correct statement for topoisomerase is?

(a) They act only on double stranded molecules

(b) They alter the degree of supercoiling of DNA molecules

(c) They are less effective than conventional DNA ligase

(d) There are three types of topoisomerases

I have been asked this question during an interview.

The above asked question is from Enzymes for Ligation in portion Basics of Genetic Engineering of Genetic Engineering

Answer 1

The correct option is (b) They alter the degree of supercoiling of DNA molecules

Best explanation: Topoisomerases alter the degree of supercoiling of both single and double stranded DNA molecules. There are two types of topoisomerases, I and II. I is responsible for altering single stranded molecules and type II for altering double stranded molecules. They are more effective than conventional DNA ligase.