3CTZ

Structure of human cytosolic X-prolyl aminopeptidase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.154 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of human cytosolic X-prolyl aminopeptidase: a double Mn(II)-dependent dimeric enzyme with a novel three-domain subunit

Li, X.Lou, Z.Li, X.Zhou, W.Ma, M.Cao, Y.Geng, Y.Bartlam, M.Zhang, X.C.Rao, Z.

(2008) J.Biol.Chem. 283: 22858-22866

  • DOI: 10.1074/jbc.M710274200

  • PubMed Abstract: 
  • X-prolyl aminopeptidases catalyze the removal of a penultimate prolyl residue from the N termini of peptides. Mammalian X-prolyl aminopeptidases are shown to be responsible for the degradation of bradykinin, a blood pressure regulator peptide, and ha ...

    X-prolyl aminopeptidases catalyze the removal of a penultimate prolyl residue from the N termini of peptides. Mammalian X-prolyl aminopeptidases are shown to be responsible for the degradation of bradykinin, a blood pressure regulator peptide, and have been linked to myocardial infarction. The x-ray crystal structure of human cytosolic X-prolyl aminopeptidase (XPN-PEP1) was solved at a resolution of 1.6 angstroms. The structure reveals a dimer with a unique three-domain organization in each subunit, rather than the two domains common to all other known structures of X-prolyl aminopeptidase and prolidases. The C-terminal catalytic domain of XPNPEP1 coordinates two metal ions and shares a similar fold with other prolyl aminopeptidases. Metal content analysis and activity assays confirm that the enzyme is double Mn(II) dependent for its activity, which contrasts with the previous notion that each XPNPEP1 subunit contains only one Mn(II) ion. Activity assays on an E41A mutant demonstrate that the acidic residue, which was considered as a stabilizing factor in the protonation of catalytic residue His498, plays only a marginal role in catalysis. Further mutagenesis reveals the significance of the N-terminal domain and dimerization for the activity of XPNPEP1, and we provide putative structural explanations for their functional roles. Structural comparisons further suggest mechanisms for substrate selectivity in different X-prolyl peptidases.


    Organizational Affiliation

    College of Life Sciences & Tianjin State Laboratory of Protein Sciences, Nankai University, Tianjin 300071, China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Xaa-Pro aminopeptidase 1
A
623Homo sapiensMutation(s): 0 
Gene Names: XPNPEP1 (XPNPEPL, XPNPEPL1)
EC: 3.4.11.9
Find proteins for Q9NQW7 (Homo sapiens)
Go to Gene View: XPNPEP1
Go to UniProtKB:  Q9NQW7
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN

Download SDF File 
Download CCD File 
A
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

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Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
CA
Query on CA

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Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
P6G
Query on P6G

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Download CCD File 
A
HEXAETHYLENE GLYCOL
POLYETHYLENE GLYCOL PEG400
C12 H26 O7
IIRDTKBZINWQAW-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.196 
  • R-Value Work: 0.154 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 71.444α = 90.00
b = 131.429β = 90.00
c = 169.076γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2008-04-15 
  • Released Date: 2008-05-27 
  • Deposition Author(s): Li, X., Lou, Z., Rao, Z.

Revision History 

  • Version 1.0: 2008-05-27
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2014-01-29
    Type: Database references