Choristoneura Fumiferana (Spruce Budworm) Antifreeze Protein Isoform 501

Experimental Data Snapshot

  • Resolution: 2.45 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.221 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


A beta-helical antifreeze protein isoform with increased activity: structural and functional insights

Leinala, E.K.Davies, P.L.Doucet, D.Tyshenko, M.G.Walker, V.K.Jia, Z.

(2002) J Biol Chem 277: 33349-33352

  • DOI: https://doi.org/10.1074/jbc.M205575200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The insect spruce budworm (Choristoneura fumiferana)(Cf) produces a number of isoforms of its highly active antifreeze protein (CfAFP). Although most of the CfAFP isoforms are in the 9-kDa range, isoforms containing a 30- or 31-amino acid insertion have also been identified. Here we describe the functional and structural analysis of a selected long isoform, CfAFP-501. X-ray crystal structure determination reveals that the 31-amino acid insertion found in CfAFP-501 forms two additional loops within its highly regular beta-helical structure. This effectively extends the area of the two-dimensional Thr array and ice-binding surface of the protein. The larger isoform has 3 times the thermal hysteresis activity of the 9-kDa CfAFP-337. As well, a deletion of the 31-amino acid insertion within CfAFP-501 to form CfAFP-501-Delta-2-loop, results in a protein with reduced activity similar to the shorter CfAFP isoforms. Thus, the enhanced antifreeze activity of CfAFP-501 is directly correlated to the length of its beta-helical structure and hence the size of its ice-binding face.

  • Organizational Affiliation

    Departments of Biochemistry and Biology, Queen's University, Kingston, Ontario, K7L 3N6 Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Antifreeze protein isoform 501
A, B, C, D
121Choristoneura fumiferanaMutation(s): 0 
Find proteins for Q9GSA6 (Choristoneura fumiferana)
Explore Q9GSA6 
Go to UniProtKB:  Q9GSA6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9GSA6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.45 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.221 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.9α = 90
b = 57.4β = 92.1
c = 70.13γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-09-18
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-24
    Changes: Database references