Question

The recognition sequence for BamHI is 5’ G|GATCC 3’. The ‘|’ represents the cutting site. What can be inferred about the ends from it?

(a) The ends created are double stranded

(b) The single stranded end is 5’ in nature

(c) The single stranded end is 3’ in nature

(d) To decide about the nature of the ends more information is needed

I have been asked this question during an online interview.

This is a very interesting question from Restriction Endonuclease & Phosphatases in division Basics of Genetic Engineering of Genetic Engineering

Answer 1

Correct choice is (b) The single stranded end is 5’ in nature

Easy explanation: The other strand is just complementary to it and can be written in the following way:

5’ G|GATCC 3’

3’ CCTAG|G 5’

After cleavage, the sequences are represented as:

5’ G 3’            5’ GATCC 3’

3’ CCTAG 5’             3’ G 5’

Thus, we can see that the ends generated are single stranded at 5’ end.