3P92

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.159 
  • R-Value Work: 0.111 
  • R-Value Observed: 0.115 

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:  
    3P95, 3P92

  • 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:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PRSS3 proteinA224Homo sapiensMutation(s): 1 
Gene Names: PRSS3PRSS4TRY3TRY4
EC: 3.4.21.4
Find proteins for P35030 (Homo sapiens)
Explore P35030 
Go to UniProtKB:  P35030
NIH Common Fund Data Resources
PHAROS  P35030
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Pancreatic trypsin inhibitorE58Bos taurusMutation(s): 2 
Find proteins for P00974 (Bos taurus)
Explore P00974 
Go to UniProtKB:  P00974
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.159 
  • R-Value Work: 0.111 
  • R-Value Observed: 0.115 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 44.282α = 90
b = 39.222β = 100.28
c = 68.807γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
PHASERphasing
PHENIXrefinement
PDB_EXTRACTdata extraction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

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