Question

Which one of the following restriction endonucleases is a blunt cutter?

• A. BamHI
• B. EcoRI
• C. HindIII
• D. EcoRV

Hint:

When working with restriction enzymes, it is important to know whether the enzyme generates sticky or blunt ends, as this affects how the DNA can be ligated with other fragments.

Answer 1

The Correct Option is D

Restriction endonucleases are enzymes that cut DNA at specific sequences. They can generate either sticky ends (overhanging ends) or blunt ends (straight cuts). EcoRV is a restriction enzyme that cuts DNA in a blunt-ended fashion. It recognizes the palindromic sequence 5'–GATATC–3' and cuts both strands of the DNA at the same position, generating blunt ends. Thus, statement (D) is correct.
- (A): BamHI is a restriction enzyme that produces sticky ends, not blunt ends. It recognizes the sequence 5'–GGATCC–3', cutting between the G and the A. Hence, statement (A) is incorrect.
- (B): EcoRI is another restriction enzyme that creates sticky ends. It cuts between the G and the A of the sequence 5'–GAATTC–3'. Therefore, statement (B) is incorrect.
- (C): HindIII also generates sticky ends. It recognizes the sequence 5'–AAGCTT–3' and cuts between the A and the A. Thus, statement (C) is incorrect.
Thus, the correct answer is (D).