4BD9

Structure of the complex between SmCI and human carboxypeptidase A4


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.223 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

A Noncanonical Mechanism of Carboxypeptidase Inhibition Revealed by the Crystal Structure of the Tri-Kunitz Smci in Complex with Human Cpa4.

Alonso Del Rivero, M.Reytor, M.L.Trejo, S.A.Chavez, M.A.Aviles, F.X.Reverter, D.

(2013) Structure 21: 1118

  • DOI: 10.1016/j.str.2013.04.021

  • PubMed Abstract: 
  • The crystal structure of SmCI (Sabellastarte magnifica carboxypeptidase inhibitor) has been determined in complex with human carboxypeptidase A4 (hCPA4). SmCI is composed by three BPTI/Kunitz domains, each one displaying high structural homology and ...

    The crystal structure of SmCI (Sabellastarte magnifica carboxypeptidase inhibitor) has been determined in complex with human carboxypeptidase A4 (hCPA4). SmCI is composed by three BPTI/Kunitz domains, each one displaying high structural homology and functionality with serine protease inhibitors. Moreover, SmCI possesses a distinctive capability to inhibit metallo-carboxypeptidases, constituting a bifunctional metallocarboxy- and serine protease inhibitor. The structure of the 1:1 complex of SmCI with hCPA4 reveals a noncanonical mechanism of carboxypeptidase inhibition, which surprisingly occurs mainly via the N-terminal segment, which penetrates into the active site groove of the enzyme. Mutagenesis and biochemical analysis confirm the major role of the N-terminal segment in the inhibition of carboxypeptidases. SmCI represents a tri-Kunitz serine protease inhibitor adapted to inhibit metallo-carboxypeptidases and discloses an unusual mechanism of inhibition by the N-terminal segment, emulating the "classical" C-terminal substrate-like inhibition.


    Organizational Affiliation

    Centro de Estudio de Proteínas, Facultad de Biología, Universidad de la Habana, Cuba 10400.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CARBOXYPEPTIDASE A4
A
310Homo sapiensGene Names: CPA4 (CPA3)
EC: 3.4.17.-
Find proteins for Q9UI42 (Homo sapiens)
Go to Gene View: CPA4
Go to UniProtKB:  Q9UI42
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
CARBOXYPEPTIDASE INHIBITOR SMCI
B
165Sabellastarte magnificaN/A
Find proteins for P84875 (Sabellastarte magnifica)
Go to UniProtKB:  P84875
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.254 
  • R-Value Work: 0.223 
  • Space Group: P 65 2 2
Unit Cell:
Length (Å)Angle (°)
a = 138.670α = 90.00
b = 138.670β = 90.00
c = 161.560γ = 120.00
Software Package:
Software NamePurpose
MOLREPphasing
PHENIXrefinement
SCALAdata scaling
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-07-17
    Type: Initial release