Crystal structure of imaginal disc growth factor-2

Experimental Data Snapshot

  • Resolution: 1.30 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.176 

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This is version 2.1 of the entry. See complete history


Crystal structure of imaginal disc growth factor-2. A member of a new family of growth-promoting glycoproteins from Drosophila melanogaster.

Varela, P.F.Llera, A.S.Mariuzza, R.A.Tormo, J.

(2002) J Biol Chem 277: 13229-13236

  • DOI: https://doi.org/10.1074/jbc.M110502200
  • Primary Citation of Related Structures:  
    1JND, 1JNE

  • PubMed Abstract: 

    Imaginal disc growth factor-2 (IDGF-2) is a member of a recently described family of Drosophila melanogaster-soluble polypeptide growth factors that promote cell proliferation in imaginal discs. Although their precise mode of action has not been established, IDGFs cooperate with insulin in stimulating the growth of imaginal disc cells. We report the crystal structure of IDGF-2 at 1.3-A resolution. The structure shows the classical (betaalpha)(8) barrel-fold of family 18 glycosyl hydrolases, with an insertion of an alpha + beta domain similar to that of Serratia marcescens chitinases A and B. However, amino acid substitutions in the consensus catalytic sequence of chitinases give IDGF-2 a less negatively charged environment in its putative ligand-binding site and preclude the nucleophilic attack mechanism of chitin hydrolysis. Particularly important is the replacement of Glu by Gln at position 132, which has been shown to abolish enzymatic activity in chitinases. Nevertheless, a modest conservation of residues that participate in oligosaccharide recognition suggests that IDGF-2 could bind carbohydrates, assuming several conformational changes to open the partially occluded binding site. Thus, IDGFs may have evolved from chitinases to acquire new functions as growth factors, interacting with cell surface glycoproteins implicated in growth-promoting processes, such as the Drosophila insulin receptor.

  • Organizational Affiliation

    Center for Advanced Research in Biotechnology, W. M. Keck Laboratory of Structural Biology, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Imaginal disc growth factor-2420Drosophila melanogasterMutation(s): 0 
Find proteins for Q9V3D4 (Drosophila melanogaster)
Explore Q9V3D4 
Go to UniProtKB:  Q9V3D4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9V3D4
Sequence Annotations
  • Reference Sequence


Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
Glycosylation Resources
GlyTouCan:  G81315DD
GlyCosmos:  G81315DD
GlyGen:  G81315DD
Experimental Data & Validation

Experimental Data

  • Resolution: 1.30 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.176 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.345α = 90
b = 106.345β = 90
c = 89.987γ = 120
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: 2002-05-01
    Type: Initial release
  • Version 1.1: 2007-10-21
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Database references, Derived calculations, Structure summary
  • Version 2.1: 2023-08-16
    Changes: Data collection, Database references, Refinement description, Structure summary