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Catalytic Site Atlas Search Results
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Catalytic Site Atlas

CSA LITERATURE entry for 1w0h

E.C. name3-5 EXONUCLEASE ERI1
SpeciesHomo sapiens (Human)
E.C. Number (IntEnz) 3.1.-.-
CSA Homologues of 1w0h
CSA Entries With UniProtID
CSA Entries With EC Number 3.1.-.-
PDBe Entry 1w0h
PDBSum Entry 1w0h
MACiE Entry 1w0h

Literature Report

Introduction3'-5' exoribonuclease (3'hExo) from Homo sapiens is a DEDDh family member. It contains the invariant DEDD working with H sequence of residues. 3'hExo targets human histone mRNAs and degrades them in a 3' to 5' direction in a sequence specific manner.
Mechansim1. His 293 acts as a general base by deprotonating a water molecule, activating it for nucleophilic attack. 2. The activated water molecule nucleophilically attacks the last phosphorus atom, breaking the phosphodiester bond of the terminal residue of the oligonucleotide chain. 3. A negatively charged, pentacoordinate intermediate is formed, which is stabilised by the MgA ion. 4. Glu 136 deprotonates the O atom of the intermediate, collapsing it to form the products.

Catalytic Sites for 1w0h

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
GluA136136macie:sideChainDeprotonates the pentacoordinate intermediate, causing it to collapse to form the products.
HisA293293macie:sideChainActs as a general base by deprotonating a water molecule, activating it for nucleophilic attack.

Literature References

Notes:
Cheng Y
Crystallographic structure of the nuclease domain of 3'hExo, a DEDDh family member, bound to rAMP.
J Mol Biol 2004 343 305-312
PubMed: 15451662
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