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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1a16

E.C. nameXaa-Pro aminopeptidase
SpeciesEscherichia coli (Bacteria)
E.C. Number (IntEnz) 3.4.11.9
CSA Homologues of 1a16There are 118 Homologs
CSA Entries With UniProtID P15034
CSA Entries With EC Number 3.4.11.9
PDBe Entry 1a16
PDBSum Entry 1a16
MACiE Entry 1a16

Literature Report

IntroductionAminopeptidase P cleaves an Xaa-Pro bond at the N-terminal of a polypeptide (even a dipeptide or tripeptide), where Xaa can be any amino acid. It is part of the peptidase M24B family.
MechansimA hydroxide ion complexed between two manganese (II) ions is the nucleophile for this reaction. It is further activated by a hydrogen bond to glutamate. The nucleophile attacks the carbonyl of the substrate, and the negatively charged tetrahedral intermediate is stabilised by an oxyanion hole. When the intermediate collapses the peptide bond is broken and the products (the C-terminal peptide and the N-terminal amino acid) are released. A solvent water molecule enters the active site to replace the original hydroxide ion.
Reaction

Catalytic Sites for 1a16

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
HisA361362macie:sideChainForms the oxyanion hole to stabilise the negative charge on the tetrahedral intermediate. Also suggested as part of a proton shuttle.
GluA383384macie:sideChainActivates hydroxide ion as a nucleophile.
HisA243244macie:sideChainSuggested as part of a proton shuttle based on similarity to arginase.
HisA350351macie:sideChainSuggested as part of a proton shuttle based on similarity to arginase.

Literature References

Notes:
Wilce MC
Structure and mechanism of a proline-specific aminopeptidase from Escherichia coli.
Proc Natl Acad Sci U S A 1998 95 3472-3477
PubMed: 9520390
Kanyo ZF
Structure of a unique binuclear manganese cluster in arginase.
Nature 1996 383 554-557
PubMed: 8849731
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