3SO3

Structures of Fab-Protease Complexes Reveal a Highly Specific Non-Canonical Mechanism of Inhibition.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.161 

wwPDB Validation 3D Report Full Report


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Literature

A reverse binding motif that contributes to specific protease inhibition by antibodies.

Schneider, E.L.Lee, M.S.Baharuddin, A.Goetz, D.H.Farady, C.J.Ward, M.Wang, C.I.Craik, C.S.

(2012) J.Mol.Biol. 415: 699-715

  • DOI: 10.1016/j.jmb.2011.11.036
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The type II transmembrane serine protease family consists of 18 closely related serine proteases that are implicated in multiple functions. To identify selective, inhibitory antibodies against one particular type II transmembrane serine protease, mat ...

    The type II transmembrane serine protease family consists of 18 closely related serine proteases that are implicated in multiple functions. To identify selective, inhibitory antibodies against one particular type II transmembrane serine protease, matriptase [MT-SP1 (membrane-type serine protease 1)], a phage display library was created with a natural repertoire of Fabs [fragment antigen binding (Fab)] from human naïve B cells. Fab A11 was identified with a 720 pM inhibition constant and high specificity for matriptase over other trypsin-fold serine proteases. A Trichoderma reesei system expressed A11 with a yield of ∼200 mg/L. The crystal structure of A11 in complex with matriptase has been determined and compared to the crystal structure of another antibody inhibitor (S4) in complex with matriptase. Previously discovered from a synthetic single-chain variable fragment library, S4 is also a highly selective and potent matriptase inhibitor. The crystal structures of the A11/matriptase and S4/matriptase complexes were solved to 2.1 Å and 1.5 Å, respectively. Although these antibodies, discovered from separate libraries, interact differently with the protease surface loops for their specificity, the structures reveal a similar novel mechanism of protease inhibition. Through the insertion of the H3 variable loop in a reverse orientation at the substrate-binding pocket, these antibodies bury a large surface area for potent inhibition and avoid proteolytic inactivation. This discovery highlights the critical role that the antibody scaffold plays in positioning loops to bind and inhibit protease function in a highly selective manner. Additionally, Fab A11 is a fully human antibody that specifically inhibits matriptase over other closely related proteases, suggesting that this approach could be useful for clinical applications.


    Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California, San Francisco, Genentech Hall, San Francisco, CA 94143-2280, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Suppressor of tumorigenicity 14 protein
A
241Homo sapiensMutation(s): 1 
Gene Names: ST14 (PRSS14, SNC19, TADG15)
EC: 3.4.21.109
Find proteins for Q9Y5Y6 (Homo sapiens)
Go to Gene View: ST14
Go to UniProtKB:  Q9Y5Y6
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
A11 FAB light chain
B
217N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
A11 FAB heavy chain
C
228N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SUC
Query on SUC

Download SDF File 
Download CCD File 
B
SUCROSE
C12 H22 O11
CZMRCDWAGMRECN-UGDNZRGBSA-N
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.161 
  • Space Group: P 64
Unit Cell:
Length (Å)Angle (°)
a = 130.598α = 90.00
b = 130.598β = 90.00
c = 96.941γ = 120.00
Software Package:
Software NamePurpose
PHASERphasing
HKL-2000data collection
SCALAdata scaling
StructureStudiodata collection
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-06-20
    Type: Initial release