6F1F

The methylene thioacetal BPTI (Bovine Pancreatic Trypsin Inhibitor) mutant structure


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.716 Å
  • R-Value Free: 0.207 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

BPTI folding revisited: switching a disulfide into methylene thioacetal reveals a previously hidden path.

Mousa, R.Lansky, S.Shoham, G.Metanis, N.

(2018) Chem Sci 9: 4814-4820

  • DOI: 10.1039/c8sc01110a

  • PubMed Abstract: 
  • Bovine pancreatic trypsin inhibitor (BPTI) is a 58-residue protein that is stabilized by three disulfide bonds at positions 5-55, 14-38 and 30-51. Widely studied for about 50 years, BPTI represents a folding model for many disulfide-rich proteins. In ...

    Bovine pancreatic trypsin inhibitor (BPTI) is a 58-residue protein that is stabilized by three disulfide bonds at positions 5-55, 14-38 and 30-51. Widely studied for about 50 years, BPTI represents a folding model for many disulfide-rich proteins. In the study described below, we replaced the solvent exposed 14-38 disulfide bond with a methylene thioacetal bridge in an attempt to arrest the folding pathway of the protein at its two well-known intermediates, N' and N*. The modified protein was expected to be unable to undergo the rate-determining step in the widely accepted BPTI folding mechanism: the opening of the 14-38 disulfide bond followed by rearrangements that leads to the native state, N. Surprisingly, instead of halting BPTI folding at N' and N*, we uncovered a hidden pathway involving a direct reaction between the N* intermediate and the oxidizing reagent glutathione (GSSG) to form the disulfide-mixed intermediate N*-SG, which spontaneously folds into N. On the other hand, N' was unable to fold into N. In addition, we found that the methylene thioacetal bridge enhances BPTI stability while fully maintaining its structure and biological function. These findings suggest a general strategy for enhancing protein stability without compromising on function or structure, suggesting potential applications for future therapeutic protein production.


    Organizational Affiliation

    Institute of Chemistry , The Hebrew University of Jerusalem , Jerusalem , 91904 , Israel . Email: metanis@mail.huji.ac.il.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Pancreatic trypsin inhibitor
A, B, C, D, E
58Bos taurusMutation(s): 0 
Find proteins for P00974 (Bos taurus)
Go to UniProtKB:  P00974
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B, C, D, E
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B, C, E
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
SMC
Query on SMC
A, B, C, D, E
L-PEPTIDE LINKINGC4 H9 N O2 SCYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.716 Å
  • R-Value Free: 0.207 
  • R-Value Work: 0.189 
  • Space Group: P 64 2 2
Unit Cell:
Length (Å)Angle (°)
a = 95.510α = 90.00
b = 95.510β = 90.00
c = 157.130γ = 120.00
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2018-07-18
    Type: Initial release