Which of the following are correct about EcoRI? Choose the correct answer from the options given below:
- B, C, E only
- A, D, E only
- A, C, D only
- B, C, D only
Answer
(4) B, C, D only
Solution
EcoRI is a restriction endonuclease (not an exonuclease), so E is incorrect.
It recognises the specific palindromic sequence 5'-GAATTC-3' (C is correct) and cuts each strand between G and A (D is correct).
Since it cuts the two strands a little away from the centre of the palindrome, it leaves single-stranded overhangs, i.e. sticky ends (B is correct, A is incorrect).
Correct: B, C, D.
Answer: (4)