Question

Restriction enzyme(s) of recombinant DNA technology that make staggered cuts leaving sticky ends is/are

• A. EcoRI
• B. HindIII
• C. All of the above.
• D. BamHI

Answer 1

The correct option is C All of the above.

Restriction endonuclease
Restriction endonucleases are the enzymes which cleave the DNA by digesting phosphodiester bonds at the specific sequences within the DNA. Examples include EcoR I.

Types of cleavage by REN
Restriction endonucleases cut DNA in two different ways as follows:
● Blunt cuts result in non-cohesive or blunt ends.
● Staggered cuts result in cohesive or sticky ends.●
Sticky ends
Sticky end is a fragment of DNA produced by a staggered cut using restriction enzymes, in which the terminal portion has a stretch of unpaired nucleotides. Sticky ends are easy to ligate when rDNA needs to be formed. Examples include EcoR I, Hind III, BamH I etc.

EcoR I
EcoR I is the restriction enzyme obtained from Escherichia coli. It recognises the palindromic sequence 5' - GAATTC - 3' and makes the following cut between G and A on both the strands of DNA to form sticky ends.

5' - G↓AATTC - 3'
3' - CTTAA↑G - 5'

Hind III
Restriction enzyme Hind III is obtained from Haemophilus influenzae. It produces sticky ends by making the following cut in the recognition sequence.

5' - A↓AGCTT - 3'
3’ - TTCGA↑A - 5’

BamH I
Restriction enzyme BamH I is obtained from Bacillus amyloliquefaciens. It produces sticky ends by making the following cut in the recognition sequence.

5' - G↓GATCC- 3’
3' - CCTAG↑G- 5’

Final answer
(D) All of the above