Overview for MACiE Entry M0233
EC Number: 3.1.21.- (A member of the Hydrolases, Acting on ester bonds, Endodeoxyribonucleases producing 5'-phosphomonoesters)
Enzyme Name: DNA endonuclease I-CreI
Biological Species: Chlamydomonas reinhardtii (Green algae)
Catalytic Chain UniprotKB Accession Codes:
- P05725 - DNA endonuclease I-CreI
Representative PDB Code: 1g9z - LAGLIDADG HOMING ENDONUCLEASE I-CREI / DNA PRODUCT COMPLEXWITH MAGNESIUM (Resolution = 1.80 Å).
Catalytic CATH Codes:
- This enzyme has no catalytic CATH domains assigned
"Other" CATH Codes:
Display structure information
Overall Comment: I-CreI exists as a homodimer and the active sites of the enzyme overlap. Mg901 binds to one subunit, Mg903 binds to the other and Mg902 is bound to both. Mg902 is involved in the hydrolysis of both strands of DNA while Mg901 is involved in the hydrolysis of one strand and Mg903 the other.
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Stepwise Description of the Reaction
|Step 1||Activated water, coordinated to Mg901, is the nucleophile for in-line attack on the scissile DNA phosphate. The transition state is trigonal bipyramidal. The 3'-hydroxyl leaving group coordinates to Mg902 and this favours its protonation by water.|
|Step 2||Activated water, coordinated to Mg903, is the nucleophile for in-line attack on the scissile phosphate of the other DNA strand. The transition state is trigonal bipyramidal. The 3'-hydroxyl leaving group coordinates to Mg902 and this favours its protonation by water.|
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Catalytic Residues Involved
There are no catalytic residues associated with this reaction mechanism
Metal Cofactors for M0233
- B. Chevalier et al. (2004), Biochemistry, 43, 14015-14026. Metal-dependent DNA cleavage mechanism of the I-CreI LAGLIDADG homing endonuclease.
- B. S. Chevalier et al. (2001), Nat. Struct. Biol., 8, 312-316. The homing endonuclease I-CreI uses three metals, one of which is shared between the two active sites.
Homologue information for M0233 (1g9z)
MACiE Homologues (within the PDB)
MACiE Homologues (within UniprotKB/SwissProt)
Links to this entry in other databases