EcoRI recognizes the palindromic sequence GAATTC and cuts both strands between G and A, generating four-nucleotide 5' overhangs.
What feature of EcoRI's cleavage pattern enables ligation between two DNA molecules cut by the same enzyme?
- A
EcoRI methylates the overhangs to enhance ligation.
- B
EcoRI cuts both strands at the same position, creating blunt ends that randomly join.
- C
The ends are phosphorylated by EcoRI.
- Dcheck_circle
Both fragments have complementary single-stranded overhangs that can anneal.
Explanation
EcoRI cleaves between G and A on both strands, leaving 5' AATT overhangs. Identical sticky ends from any source can base-pair and be sealed by DNA ligase, the basis of recombinant DNA cloning.