Question

The recognition sequence of Sau3A is 5’ |GATC 3’ and that for DpnI is 5’ GA|TC 3’. Which of the statements is true?

(a) The ends created by both the enzymes are compatible

(b) The ends created by both the enzymes are not-compatible

(c) The ends created by DpnI are single stranded

(d) The ends created by Sau3A are single stranded

The question was posed to me in a job interview.

My question comes from Restriction Endonuclease & Phosphatases in portion Basics of Genetic Engineering of Genetic Engineering

Answer 1

Correct choice is (b) The ends created by both the enzymes are not-compatible

Easy explanation: Though the recognition sequence is the same, the ends are not compatible. It is so because both the enzymes leave double stranded ends and thus can’t be ligated.