4JB8

Caspase-7 in Complex with DARPin C7_16


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.173 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Design, construction, and characterization of a second-generation DARPin library with reduced hydrophobicity.

Seeger, M.A.Zbinden, R.Flutsch, A.Gutte, P.G.Engeler, S.Roschitzki-Voser, H.Grutter, M.G.

(2013) Protein Sci 22: 1239-1257

  • DOI: 10.1002/pro.2312
  • Primary Citation of Related Structures:  
    4J8Y, 4JB8, 4J7W

  • PubMed Abstract: 
  • Designed ankyrin repeat proteins (DARPins) are well-established binding molecules based on a highly stable nonantibody scaffold. Building on 13 crystal structures of DARPin-target complexes and stability measurements of DARPin mutants, we have generated ...

    Designed ankyrin repeat proteins (DARPins) are well-established binding molecules based on a highly stable nonantibody scaffold. Building on 13 crystal structures of DARPin-target complexes and stability measurements of DARPin mutants, we have generated a new DARPin library containing an extended randomized surface. To counteract the enrichment of unspecific hydrophobic binders during selections against difficult targets containing hydrophobic surfaces such as membrane proteins, the frequency of apolar residues at diversified positions was drastically reduced and substituted by an increased number of tyrosines. Ribosome display selections against two human caspases and membrane transporter AcrB yielded highly enriched pools of unique and strong DARPin binders which were mainly monomeric. We noted a prominent enrichment of tryptophan residues during binder selections. A crystal structure of a representative of this library in complex with caspase-7 visualizes the key roles of both tryptophans and tyrosines in providing target contacts. These aromatic and polar side chains thus substitute the apolar residues valine, leucine, isoleucine, methionine, and phenylalanine of the original DARPins. Our work describes biophysical and structural analyses required to extend existing binder scaffolds and simplifies an existing protocol for the assembly of highly diverse synthetic binder libraries.


    Organizational Affiliation

    Department of Biochemistry, University of Zurich, 8057, Zürich, Switzerland.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Caspase-7 subunit p20 A175Homo sapiensMutation(s): 0 
Gene Names: CASP7MCH3
EC: 3.4.22.60
Find proteins for P55210 (Homo sapiens)
Explore P55210 
Go to UniProtKB:  P55210
NIH Common Fund Data Resources
PHAROS:  P55210
Protein Feature View
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Caspase-7 subunit p11 B105Homo sapiensMutation(s): 0 
Gene Names: CASP7MCH3
EC: 3.4.22.60
Find proteins for P55210 (Homo sapiens)
Explore P55210 
Go to UniProtKB:  P55210
NIH Common Fund Data Resources
PHAROS:  P55210
Protein Feature View
Expand
  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
DARPin C7_16 P171synthetic constructMutation(s): 0 
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.173 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 143.88α = 90
b = 52.51β = 96.92
c = 60.09γ = 90
Software Package:
Software NamePurpose
PHASERphasing
PHENIXrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-08-21
    Type: Initial release
  • Version 1.1: 2013-10-09
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description