Question

How do restriction endonucleases cut DNA? Explain with one example.

Answer 1

1. The enzyme scans DNA and binds to a palindromic sequence of 4-6 base pairs.
2. It hydrolyses the phosphodiester bonds on both strands, away from the centre of the site.
3. This leaves single-stranded sticky ends.
   Example: EcoRI cuts 5'-G^AATTC-3' between G and A on each strand.