Question

'EcoRI' has played a very significant role in rDNA technology.

1. Explain the convention for naming EcoRI.
2. Write the recognition site and the cleavage sites of this restriction endonuclease.

Answer 1

(I) Restriction endonucleases are named as follows:

1st alphabet represents the genus of the organism from which the enzyme is isolated.

2nd and 3rd alphabet represent the species of the organism.

4th alphabet represents the strain.

The Roman number represents the order of isolation or discovery of the enzyme.

EcoRI comes from the Escherichia coli RYB strain.

In EcoRI, 'E' comes from the genus 'Escherichia' and 'co' comes from the species name 'Coli'.

The letter 'R' is derived from the name of the strain RYB.

Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria.

(II) The recognition sequence where EcoRI cleaves the DNA molecule is G/AATTC. Such sequences have a complementary sequence, CTTAA/G, which is known as a palindromic sequence.