Question

I am a high school student and I am little confused about the uses of restriction endonucleases. Why do hydrogen bonds(base pairing) break when restriction endonucleases produce sticky ends? If they only break phosphodiester bond, should hydrogen bonds not break on their own? I searched it on few sites but didn't find any discussion.

Answer 1

Restriction endonucleases cleave DNA by breaking the phosphodiester bond and disrupting the hydrogen bonds between base pairs. This results in the formation of sticky ends that can be joined together using DNA ligase.

Step-by-step explanation:

Restriction endonucleases are enzymes that cleave DNA at specific nucleotide sequences. When they cut the DNA, they break the phosphodiester bond, which is the bond that holds the DNA strand together. However, this cleavage also disrupts the hydrogen bonds between the base pairs, causing them to break as well. The formation of sticky ends occurs when the DNA fragments are cleaved in a staggered manner, leaving overhangs that can base-pair with complementary overhangs on other DNA fragments.