A restriction enzyme is a protein that is produced by certain bacteria that cleaves DNA at some specific sites along with the molecule. You will come across several thousands of restriction enzymes. Every individual restriction enzyme is named after the bacteria which is the reason for its origin. All these enzymes are recognized and cut several hundreds of DNA sequences unique in nature, mostly having a base of 4 to 7 units long. Scientists decide which among the available restriction enzymes to be used depending on the expected result.
Types of Restriction enzyme used in Genetic engineering:
There are 2 main enzymes applied in genetic engineering. They are:
• Enzyme # 1. Restriction Endonuclease- Restriction enzymes create breaks in the palindromic sequences, and these breaks are in general are not straightway opposite to each other. These enzymes help in generating DNA fragments having complementary ends.
• Enzyme # 2. DNA Ligase- Ends of the DNA strands can be joined with the use of enzyme polynucleotide ligase, known as ‘glue’ for the recombinant DNA molecule. The Ligase enzyme catalyzes the development of the phosphodiester bond which happens between the two nucleotides 3’OH and 5’P terminals.
Working of the restriction enzymes in Genetic engineering:
To make the gene work in genetic engineering, one cannot just get it inserted straight into a cell. Initially, the researcher needs to make use of restriction enzymes for splicing or to cut out, the specific gene which they want to make use of.
That specific restriction enzyme will be used for opening the DNA in the host cell, or the vector, which will be delivering the DNA. Here the vector can be both bacterial and viral. If the target is to create a large amount of the expected gene, then bacterial cells are used to make the gene work, one cannot straightway insert the same direction inside a cavity. In the first step, scientists need to make use of restriction enzymes for splicing, the gene which they want to make use of. The particular restriction enzyme will again be used for opening the DNA located in the host cell, or the vector, which is responsible for delivering the DNA. Here the vector can be either bacterial or viral.
• If the target is the production of a large volume of the preferred gene, then bacterial cells will be purposefully used.
• On the other hand, if the aim is to get gene therapy, the application of an improved viral cell is made so that it can infect some particular parts of the cell for presenting the new and unique genetic material.
This is a brief on how is restriction enzymes used in genetic engineering by scientists.