EC Number: 18.104.22.168 (A member of the Hydrolases, Acting on ester bonds, Endoribonucleases producing 5'-phosphomonoesters)
Enzyme Name: calf thymus ribonuclease H
Biological Species: Escherichia coli (Bacteria)
Catalytic Chain UniprotKB Accession Codes:
Representative PDB Code: 1rdd - CRYSTAL STRUCTURE OF ESCHERICHIA COLI RNASE HI IN COMPLEXWITH MG2+ AT 2.8 ANGSTROMS RESOLUTION: PROOF FOR A SINGLEMG2+ SITE (Resolution = 2.80 Å).
Overall Comment: Two alternative mechanisms have been proposed for this enzyme. One is a two-metal-ion mechanism where one of the two metal ions activates the attacking hydroxide ion and the other is a general acid-base mechanism where an amino acid residue fulfils this role. NMR and kinetic studies suggest only one metal binds to this protein and that the protein is inactivated by subsequent metal binding events. This makes the general acid base mechanism more plausible . Asp134 holds the nucleophilic water molecule, Glu48 anchors the water molecule that acts as a general acid.
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Stepwise Description of the Reaction
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Catalytic Residues Involved
Metal Cofactors for M0163
Homologue information for M0163 (1rdd)
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