1W6Y

crystal structure of a mutant W92A in ketosteroid isomerase (KSI) from Pseudomonas putida biotype B


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.224 

Starting Model: experimental
View more details

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Small Exterior Hydrophobic Cluster Contributes to Conformational Stability and Steroid Binding in Ketosteroid Isomerase from Pseudomonas Putida Biotype B

Yun, Y.S.Nam, G.H.Kim, Y.-G.Oh, B.-H.Choi, K.Y.

(2005) FEBS J 272: 1999

  • DOI: https://doi.org/10.1111/j.1742-4658.2005.04627.x
  • Primary Citation of Related Structures:  
    1W6Y

  • PubMed Abstract: 

    A structural motif called the small exterior hydrophobic cluster (SEHC) has been proposed to explain the stabilizing effect mediated by solvent-exposed hydrophobic residues; however, little is known about its biological roles. Unusually, in Delta(5)-3-ketosteroid isomerase from Pseudomonas putida biotype B (KSI-PI) Trp92 is exposed to solvent on the protein surface, forming a SEHC with the side-chains of Leu125 and Val127. In order to identify the role of the SEHC in KSI-PI, mutants of those amino acids associated with the SEHC were prepared. The W92A, L125A/V127A, and W92A/L125A/V127A mutations largely decreased the conformational stability, while the L125F/V127F mutation slightly increased the stability, indicating that hydrophobic packing by the SEHC is important in maintaining stability. The crystal structure of W92A revealed that the decreased stability caused by the removal of the bulky side-chain of Trp92 could be attributed to the destabilization of the surface hydrophobic layer consisting of a solvent-exposed beta-sheet. Consistent with the structural data, the binding affinities for three different steroids showed that the surface hydrophobic layer stabilized by SEHC is required for KSI-PI to efficiently recognize hydrophobic steroids. Unfolding kinetics based on analysis of the Phi(U) value also indicated that the SEHC in the native state was resistant to the unfolding process, despite its solvent-exposed site. Taken together, our results demonstrate that the SEHC plays a key role in the structural integrity that is needed for KSI-PI to stabilize the hydrophobic surface conformation and thereby contributes both to the overall conformational stability and to the binding of hydrophobic steroids in water solution.


  • Organizational Affiliation

    Division of Molecular and Life Sciences, Pohang University of Science and Technology, South Korea.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
STEROID DELTA-ISOMERASE131Pseudomonas putidaMutation(s): 1 
EC: 5.3.3.1
UniProt
Find proteins for P07445 (Pseudomonas putida)
Explore P07445 
Go to UniProtKB:  P07445
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP07445
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.224 
  • R-Value Observed: 0.224 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 35.32α = 90
b = 95.871β = 90
c = 72.97γ = 90
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
CNSphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-04-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description