5JB5

A simplified BPTI variant containing 22 alanines out of 58 residues


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.167 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Crystal structures of highly simplified BPTIs provide insights into hydration-driven increase of unfolding enthalpy

Islam, M.M.Yohda, M.Kidokoro, S.Kuroda, Y.

(2017) Sci Rep 7: 41205-41205

  • DOI: 10.1038/srep41205
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • We report a thermodynamic and structural analysis of six extensively simplified bovine pancreatic trypsin inhibitor (BPTI) variants containing 19-24 alanines out of 58 residues. Differential scanning calorimetry indicated a two-state thermal unfoldin ...

    We report a thermodynamic and structural analysis of six extensively simplified bovine pancreatic trypsin inhibitor (BPTI) variants containing 19-24 alanines out of 58 residues. Differential scanning calorimetry indicated a two-state thermal unfolding, typical of a native protein with densely packed interior. Surprisingly, increasing the number of alanines induced enthalpy stabilization, which was however over-compensated by entropy destabilization. X-ray crystallography indicated that the alanine substitutions caused the recruitment of novel water molecules facilitating the formation of protein-water hydrogen bonds and improving the hydration shells around the alanine's methyl groups, both of which presumably contributed to enthalpy stabilization. There was a strong correlation between the number of water molecules and the thermodynamic parameters. Overall, our results demonstrate that, in contrast to our initial expectation, a protein sequence in which over 40% of the residues are alanines can retain a densely packed structure and undergo thermal denaturation with a large enthalpy change, mainly contributed by hydration.


    Organizational Affiliation

    Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Nakamachi, Koganei-shi, Tokyo 184-8588, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Pancreatic trypsin inhibitor
A, B, C
58Bos taurusMutation(s): 3 
Find proteins for P00974 (Bos taurus)
Go to UniProtKB:  P00974
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B, C
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.167 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 60.989α = 90.00
b = 99.184β = 90.00
c = 61.731γ = 90.00
Software Package:
Software NamePurpose
HKL-2000phasing
DENZOdata reduction
SCALAdata scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2016-04-13 
  • Released Date: 2017-04-19 
  • Deposition Author(s): Islam, M.M.

Revision History 

  • Version 1.0: 2017-04-19
    Type: Initial release