X-ray crystal structure of the K11S/K63S double mutant of ubiquitin

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 

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This is version 1.2 of the entry. See complete history


Enhancing ubiquitin crystallization through surface-entropy reduction.

Loll, P.J.Xu, P.Schmidt, J.T.Melideo, S.L.

(2014) Acta Crystallogr F Struct Biol Commun 70: 1434-1442

  • DOI: https://doi.org/10.1107/S2053230X14019244
  • Primary Citation of Related Structures:  
    4PIG, 4PIH, 4PIJ

  • PubMed Abstract: 

    Ubiquitin has many attributes suitable for a crystallization chaperone, including high stability and ease of expression. However, ubiquitin contains a high surface density of lysine residues and the doctrine of surface-entropy reduction suggests that these lysines will resist participating in packing interactions and thereby impede crystallization. To assess the contributions of these residues to crystallization behavior, each of the seven lysines of ubiquitin was mutated to serine and the corresponding single-site mutant proteins were expressed and purified. The behavior of these seven mutants was then compared with that of the wild-type protein in a 384-condition crystallization screen. The likelihood of obtaining crystals varied by two orders of magnitude within this set of eight proteins. Some mutants crystallized much more readily than the wild type, while others crystallized less readily. X-ray crystal structures were determined for three readily crystallized variants: K11S, K33S and the K11S/K63S double mutant. These structures revealed that the mutant serine residues can directly promote crystallization by participating in favorable packing interactions; the mutations can also exert permissive effects, wherein crystallization appears to be driven by removal of the lysine rather than by addition of a serine. Presumably, such permissive effects reflect the elimination of steric and electrostatic barriers to crystallization.

  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
75Homo sapiensMutation(s): 2 
UniProt & NIH Common Fund Data Resources
Find proteins for P62987 (Homo sapiens)
Explore P62987 
Go to UniProtKB:  P62987
PHAROS:  P62987
GTEx:  ENSG00000221983 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP62987
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.198 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 31.97α = 90
b = 48.85β = 90
c = 80.32γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-10-29
    Type: Initial release
  • Version 1.1: 2017-11-22
    Changes: Derived calculations, Other, Refinement description, Source and taxonomy
  • Version 1.2: 2023-09-27
    Changes: Data collection, Database references, Refinement description