DNA Restriction Enzyme EcoRI:
EcoRI is a type II endonuclease classified as a DNA restriction enzyme. It was initially isolated from the bacterium Escherichia coli, hence its name. EcoRI is widely used in molecular biology research and genetic engineering applications, particularly in DNA cloning and recombinant DNA technology.
This enzyme specifically recognizes and cleaves DNA sequences that are defined by a specific nucleotide sequence pattern, known as a recognition site. The recognition site for EcoRI is the palindromic hexanucleotide sequence 5'-GAATTC-3'. This means the sequence reads the same from left to right on one strand and right to left on the complementary strand.
EcoRI acts by hydrolyzing the phosphodiester bonds within the DNA molecule, creating double-stranded DNA fragments with cohesive or sticky ends. These cohesive ends have exposed unpaired bases, enabling the fragments to easily bind to complementary sequences.
The per-site cleavage efficiency of EcoRI is quite high, making it highly efficient for DNA manipulations. EcoRI is commonly used in genetic engineering techniques, such as gene cloning, where it is used to cut open a plasmid vector and insert a desired DNA fragment. Additionally, it can also be employed in restriction fragment length polymorphism (RFLP) analysis, DNA fingerprinting, and DNA sequence analysis.
In summary, EcoRI is a DNA restriction enzyme that recognizes and cleaves DNA sequences containing the characteristic GAATTC recognition site, producing fragments with cohesive ends. It plays a crucial role in various molecular biology techniques, allowing scientists to manipulate DNA molecules for a wide range of applications.
