
EcoRII (pronounced 'eco R two') is an Restriction endonuclease enzyme (REase) of the restriction modification system (RM) naturally found in Escherichia coli, a Gram-negative bacteria. Its molecular mass is 45.2 kDa, being composed of 402 amino acids.
EcoRII is a bacterial Type IIE REase that interacts with two or three copies of the pseudopalindromic DNA recognition sequence 5'-CCWGG-3' (W = A or T), one being the actual target of cleavage, the other(s) serving as the allosteric activator(s). EcoRII cuts the target DNA sequence CCWGG, generating sticky ends.
| Recognition site | Cut results |
5' NNCCWGGNN 3' NNGGWCCNN |
5' NN CCWGGNN 3' NNGGWCC NN |
| Restriction endonuclease EcoRII, N-terminal | |||||||
|---|---|---|---|---|---|---|---|
crystal structure of restriction endonuclease ecorii mutant r88a | |||||||
| Identifiers | |||||||
| Symbol | EcoRII-N | ||||||
| Pfam | PF09217 | ||||||
| Pfam clan | CL0405 | ||||||
| InterPro | IPR015300 | ||||||
| SCOP2 | 1na6 / SCOPe / SUPFAM | ||||||
| |||||||
| EcoRII C terminal | |||||||
|---|---|---|---|---|---|---|---|
crystal structure of restriction endonuclease ecorii mutant r88a | |||||||
| Identifiers | |||||||
| Symbol | EcoRII-C | ||||||
| Pfam | PF09019 | ||||||
| Pfam clan | CL0236 | ||||||
| InterPro | IPR015109 | ||||||
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The apo crystal structure of EcoRII mutant R88A (PDB: 1NA6) has been solved at 2.1 Å resolution. The EcoRII monomer has two domains, N-terminal and C-terminal, linked through a hinge loop.
The N-terminal effector-binding domain has an archetypal DNA-binding pseudobarrel fold (SCOP 101936) with a prominent cleft. Structural superposition showed it is evolutionarily related to:
The C-terminal catalytic domain has a typical restriction endonuclease-like fold (SCOP 52979) and belongs to the large (more than 30 members) restriction endonuclease superfamily (SCOP 52980).
Structure-based sequence alignment and site-directed mutagenesis identified the putative PD..D/EXK active sites of the EcoRII catalytic domain dimer that in apo structure are spatially blocked by the N-terminal domains.