What is EcoRI?

 

What is EcoRI?

EcoRI is a restriction enzyme or restriction endonuclease. It cuts the DNA double helix at a specific site. This restriction enzyme was first isolated from E.coli. These restriction enzymes derive their names from the organisms where it was first isolated from. Similarly, another restriction enzyme was named HindIII as it was isolated from Haemophilus influenzae.

Here Eco refers to Escherichia.coli. R is for the strain RY13 and I (one) as it was the first enzyme to be isolated from the given strain. So EcoRI is pronounced as Eco-R-One.

Restriction enzymes present in bacteria are a defence mechanism to protect against bacteriophage. Due to methylation, bacterial DNA remains unaffected.

Read on to know more about EcoRI.

Key Features of EcoRI

  • EcoRI was discovered in Herbert Boyer’s lab.
  • It is a type II restriction enzyme, which cuts specifically at the restriction site having 5’-GAATTC-3’ sequence.
  • It cuts the DNA at a specific site forming sticky ends.
  • Restriction site of EcoRI is a palindrome and it cuts DNA after G forming sticky ends with AATT.
  • The complementary sequence of DNA for G/AATTC is CTTAA/G, where ‘/’ denotes the site where peptide bond is broken.

The cutting pattern of EcoRI is-

EcoRI Restriction Site

  • EcoRI consists of 377 amino acids and has a molecular weight of 31kDa. It is a homodimer.
  • Just like other restriction enzymes, EcoRI is used in recombinant DNA technology and molecular genetics. They are used for cutting viral DNAs and plasmids forming sticky ends, which are easy to ligate.

Comments

Post a Comment

Popular posts from this blog

pBR322 Plasmid

Image
  pBR322 Plasmid The main characteristics of pBR322 are: Restriction sites:  BamH I, Hind III, Sal I, Pvu I, Pvu II, Pst I, EcoR I, Cla I Selectable marker:  antibiotic resistance genes for ampicillin (amp R ) and tetracycline (tet R ) ORI:  the origin of replication ROP:  It codes for proteins, which are involved in the process of replication of plasmid Different antibiotic resistance genes act as a restriction site and to ligate foreign DNA and for the selection of transformants. The gene, where the foreign DNA is inserted becomes inactive. Alternative selectable marker:  Mostly these have an ability to produce some colour after reacting with a chromogenic substance. The alternative markers are used for the ease of differentiating recombinants from non-recombinants, e.g. gene coding for β-galactosidase. When a foreign gene is inserted between the gene coding for β-galactosidase ,  the recombinant cell does not produce the enzyme β-galactosidase due to inactivation of the gene. In the
Read more

What is Plasmid?

  What is Plasmid? Plasmids  are extrachromosomal DNA molecules. They are small, circular and have an ability to replicate autonomously. Replication of plasmid is not under the control of chromosomal DNA. They are mostly found in bacteria. Some of the eukaryotes like yeast and plants also contain plasmids. Their ability to replicate independently makes plasmid a cloning vector in the recombinant DNA technology for transferring and manipulating genes. Many antibiotic-resistant genes in bacteria are present in plasmids. The size of plasmid varies from a few base pairs to thousands of bp. Plasmids also get transferred from one bacterial cell to another by the process of conjugation. Plasmids carrying a specific gene are introduced into bacterial cells, which multiply rapidly and the required DNA fragment is produced in larger quantities. Plasmids are used to prepare a recombinant DNA with the desired gene to transfer genes from one organism to another. This is known as genetic engineering
Read more