Explain briefly Restriction enzymes and DNA
Restriction enzymes are molecular scissors used in molecular biology for cutting DNA sequences from a specific site. It plays an important role in gene manipulation. The enzymes recognize a specific six-box pair sequence known as the recognition sequence and cut the sequence at a specific site. For example, the recognition site for enzyme ECORI is as follows:
Restriction enzyme are categorized into two types −
(i) Exonuclease − It is a type of restriction enzyme that removes the nucleotide from either 5’ or 3’ ends of the DNA molecule.
(ii) Endonuclease − It is a type of restriction enzyme that makes a cut within the DNA at a specific site. This enzyme acts as an important tool in genetic engineering. It is commonly used to make a cut in the sequence to obtain DNA fragments with sticky ends, which are later joined by enzyme DNA ligase