Experimental Data Snapshot

  • Resolution: 1.25 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 

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This is version 1.4 of the entry. See complete history


Structural basis for the binding of a globular antifreeze protein to ice.

Jia, Z.DeLuca, C.I.Chao, H.Davies, P.L.

(1996) Nature 384: 285-288

  • DOI: https://doi.org/10.1038/384285a0
  • Primary Citation of Related Structures:  
    1MSI, 3NLA, 3RDN

  • PubMed Abstract: 

    Antifreeze proteins (AFPs) have the unique ability to adsorb to ice and inhibit its growth. Many organisms ranging from fish to bacteria use AFPs to retard freezing or lessen the damage incurred upon freezing and thawing. The ice-binding mechanism of the long linear alpha-helical type I AFPs has been attributed to their regularly spaced polar residues matching the ice lattice along a pyramidal plane. In contrast, it is not known how globular antifreeze proteins such as type III AFP that lack repeating ice-binding residues bind to ice. Here we report the 1.25 A crystal structure of recombinant type III AFP (QAE isoform) from eel pout (Macrozoarces americanus), which reveals a remarkably flat amphipathic ice-binding site where five hydrogen-bonding atoms match two ranks of oxygens on the [1010] ice prism plane in the <0001> direction, giving high ice-binding affinity and specificity. This binding site, substantiated by the structures and properties of several ice-binding site mutants, suggests that the AFP occupies a niche in the ice surface in which it covers the basal plane while binding to the prism face.

  • Organizational Affiliation

    Department of Biochemistry, Queen's University, Kingston, Ontario, Canada. jia@crystal.biochem.queensu.ca

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
TYPE III ANTIFREEZE PROTEIN ISOFORM HPLC 1270Zoarces americanusMutation(s): 1 
Find proteins for P19614 (Zoarces americanus)
Explore P19614 
Go to UniProtKB:  P19614
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP19614
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.25 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 32.328α = 90
b = 38.893β = 90
c = 45.483γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-12-24
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Data collection, Database references, Other
  • Version 1.4: 2024-02-14
    Changes: Data collection