Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 
  • Selection Criteria: AVERAGE 

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Refined solution structure of type III antifreeze protein: hydrophobic groups may be involved in the energetics of the protein-ice interaction.

Sonnichsen, F.D.DeLuca, C.I.Davies, P.L.Sykes, B.D.

(1996) Structure 4: 1325-1337

  • DOI: https://doi.org/10.1016/s0969-2126(96)00140-2
  • Primary Citation of Related Structures:  
    1KDE, 1KDF

  • PubMed Abstract: 

    Antifreeze proteins are found in certain fish inhabiting polar sea water. These proteins depress the freezing points of blood and body fluids below that of the surrounding sea water by binding to and inhibiting the growth of seed ice crystals. The proteins are believed to bind irreversibly to growing ice crystals in such a way as to change the curvature of the ice-water interface, leading to freezing point depression, but the mechanism of high-affinity ice binding is not yet fully understood. The solution structure of the type III antifreeze protein was determined by multidimensional NMR spectroscopy. Twenty-two structures converged and display a root mean square difference from the mean of 0.26 A for backbone atoms and 0.62 A for all non-hydrogen atoms. The protein exhibits a compact fold with a relatively large hydrophobic core, several short and irregular beta sheets and one helical turn. The ice-binding site, which encompasses parts of the C-terminal sheet and a loop, is planar and relatively nonpolar. The site is further characterized by the low solvent accessibilities and the specific spatial arrangement of the polar side-chain atoms of the putative ice-binding residues Gln9, Asn14, Thr15, Thr18 and Gln44. In agreement with the adsorption-inhibition mechanism of action, interatomic distances between active polar protein residues match the spacing of water molecules in the prism planes (¿10&1macr;0¿) of the hexagonal ice crystal. The particular side-chain conformations, however, limit the number and strength of possible proten-ice hydrogen bonds. This suggests that other entropic and enthalpic contributions, such as those arising from hydrophobic groups, could play a role in the high-affinity protein-ice adsorption.

  • Organizational Affiliation

    Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106-4970, USA. frank@herring.phol.cwru.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ANTIFREEZE PROTEIN70Zoarces americanusMutation(s): 2 
Gene Names: K38
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

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 
  • Selection Criteria: AVERAGE 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-04-21
    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: Database references, Derived calculations, Other
  • Version 1.4: 2024-05-22
    Changes: Data collection