Question

Explain briefly Restriction enzymes and DNA.

Answer 1

In the field of biotechnology restriction enzymes play an important role to map DNA as well as cutting it at specific locations for use in genetic engineering.

Complete answer:
Enzymes are the biocatalysts, these are proteins that accelerate the rate of a chemical reaction, and restriction enzymes are one type of these enzymes.
An endonuclease is a group of enzymes that deals with the cleaving of nucleotide sequences in a molecule. Restriction enzymes are one of the endonuclease enzymes. It is an enzyme produced by certain bacteria that help in the cutting or cleaving of the deoxyribonucleic acid (DNA) into smaller parts or fragments in any molecule. The main difference and any other endonucleases are that restriction enzymes cleave at a particular site known as the restriction site. It is used as an important tool for genetic engineering. Bacteria use these enzymes to protect themselves from a virus known as a bacteriophage (i.e. bacteria eater). These restriction enzymes bind to the DNA and cut each of the two-strands of double-helix at specific locations in their sugar-phosphate backbones. Bacteria also protect their degradation by taking help from the enzyme known as methylase, this enzyme produces methyl groups in the recognized site.
Naturally occurring restriction enzymes can be classified into three major types i.e. Type I, Type II, and Type III. They are classified based on their composition, nature of their target, cleavage position, and their enzyme cofactors. Type I enzymes are classified by their DNA cleavage sites and they cut far away from the recognition site. Type II enzymes recognize the site and restriction digestion (DNA cleavage) occurs at the same place. Type III enzymes are multifunctional proteins and this restriction enzyme cuts DNA away from the recognition sequence.

Note: Restriction enzyme has properties that are useful in recombinant DNA technology as they cut DNA into smaller fragments which are suitable for cloning, whereas many restriction enzymes make the staggered cut that creates single-stranded sticky ends to the formation of recombinant DNA.