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.

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