3P92

Human mesotrypsin complexed with bovine pancreatic trypsin inhibitor variant (BPTI-K15R/R17G)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5992 Å
  • R-Value Free: 0.159 
  • R-Value Work: 0.111 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The P2' residue is a key determinant of mesotrypsin specificity: engineering a high-affinity inhibitor with anticancer activity.

Salameh, M.A.Soares, A.S.Hockla, A.Radisky, D.C.Radisky, E.S.

(2011) Biochem.J. 440: 95-105

  • DOI: 10.1042/BJ20110788
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • PRSS3/mesotrypsin is an atypical isoform of trypsin, the up-regulation of which has been implicated in promoting tumour progression. Mesotrypsin inhibitors could potentially provide valuable research tools and novel therapeutics, but small-molecule t ...

    PRSS3/mesotrypsin is an atypical isoform of trypsin, the up-regulation of which has been implicated in promoting tumour progression. Mesotrypsin inhibitors could potentially provide valuable research tools and novel therapeutics, but small-molecule trypsin inhibitors have low affinity and little selectivity, whereas protein trypsin inhibitors bind poorly and are rapidly degraded by mesotrypsin. In the present study, we use mutagenesis of a mesotrypsin substrate, APPI (amyloid precursor protein Kunitz protease inhibitor domain), and of a poor mesotrypsin inhibitor, BPTI (bovine pancreatic trypsin inhibitor), to dissect mesotrypsin specificity at the key P(2)' position. We find that bulky and charged residues strongly disfavour binding, whereas acidic residues facilitate catalysis. Crystal structures of mesotrypsin complexes with BPTI variants provide structural insights into mesotrypsin specificity and inhibition. Through optimization of the P(1) and P(2)' residues of BPTI, we generate a stable high-affinity mesotrypsin inhibitor with an equilibrium binding constant K(i) of 5.9 nM, a >2000-fold improvement in affinity over native BPTI. Using this engineered inhibitor, we demonstrate the efficacy of pharmacological inhibition of mesotrypsin in assays of breast cancer cell malignant growth and pancreatic cancer cell invasion. Although further improvements in inhibitor selectivity will be important before clinical potential can be realized, the results of the present study support the feasibility of engineering protein protease inhibitors of mesotrypsin and highlight their therapeutic potential.


    Organizational Affiliation

    Department of Cancer Biology, Mayo Clinic Cancer Center, Jacksonville, FL 32224, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PRSS3 protein
A
224Homo sapiensMutation(s): 1 
Gene Names: PRSS3 (PRSS4, TRY3, TRY4)
EC: 3.4.21.4
Find proteins for P35030 (Homo sapiens)
Go to Gene View: PRSS3
Go to UniProtKB:  P35030
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Pancreatic trypsin inhibitor
E
58Bos taurusMutation(s): 2 
Find proteins for P00974 (Bos taurus)
Go to UniProtKB:  P00974
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5992 Å
  • R-Value Free: 0.159 
  • R-Value Work: 0.111 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 44.282α = 90.00
b = 39.222β = 100.28
c = 68.807γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
PHASERphasing
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-08-31
    Type: Initial release
  • Version 1.1: 2011-11-09
    Type: Database references
  • Version 1.2: 2014-10-08
    Type: Structure summary