3AAK

Crystal structure of Zn2+-bound form of des3-20ALG-2F122A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.252 
  • R-Value Observed: 0.254 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Molecular basis for defect in Alix-binding by alternatively spliced isoform of ALG-2 (ALG-2DeltaGF122) and structural roles of F122 in target recognition

Inuzuka, T.Suzuki, H.Kawasaki, M.Shibata, H.Wakatsuki, S.Maki, M.

(2010) BMC Struct Biol 10: 25-25

  • DOI: https://doi.org/10.1186/1472-6807-10-25
  • Primary Citation of Related Structures:  
    3AAJ, 3AAK

  • PubMed Abstract: 

    ALG-2 (a gene product of PDCD6) belongs to the penta-EF-hand (PEF) protein family and Ca2+-dependently interacts with various intracellular proteins including mammalian Alix, an adaptor protein in the ESCRT system. Our previous X-ray crystal structural analyses revealed that binding of Ca2+ to EF3 enables the side chain of R125 to move enough to make a primary hydrophobic pocket (Pocket 1) accessible to a short fragment of Alix. The side chain of F122, facing a secondary hydrophobic pocket (Pocket 2), interacts with the Alix peptide. An alternatively spliced shorter isoform, designated ALG-2DeltaGF122, lacks Gly121Phe122 and does not bind Alix, but the structural basis of the incompetence has remained to be elucidated. We solved the X-ray crystal structure of the PEF domain of ALG-2DeltaGF122 in the Ca2+-bound form and compared it with that of ALG-2. Deletion of the two residues shortened alpha-helix 5 (alpha5) and changed the configuration of the R125 side chain so that it partially blocked Pocket 1. A wall created by the main chain of 121-GFG-123 and facing the two pockets was destroyed. Surprisingly, however, substitution of F122 with Ala or Gly, but not with Trp, increased the Alix-binding capacity in binding assays. The F122 substitutions exhibited different effects on binding of ALG-2 to other known interacting proteins, including TSG101 (Tumor susceptibility gene 101) and annexin A11. The X-ray crystal structure of the F122A mutant revealed that removal of the bulky F122 side chain not only created an additional open space in Pocket 2 but also abolished inter-helix interactions with W95 and V98 (present in alpha4) and that alpha5 inclined away from alpha4 to expand Pocket 2, suggesting acquirement of more appropriate positioning of the interacting residues to accept Alix. We found that the inability of the two-residue shorter ALG-2 isoform to bind Alix is not due to the absence of bulky side chain of F122 but due to deformation of a main-chain wall facing pockets 1 and 2. Moreover, a residue at the position of F122 contributes to target specificity and a smaller side chain is preferable for Alix binding but not favored to bind annexin A11.


  • Organizational Affiliation

    Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Programmed cell death protein 6172Homo sapiensMutation(s): 1 
UniProt & NIH Common Fund Data Resources
Find proteins for O75340 (Homo sapiens)
Explore O75340 
Go to UniProtKB:  O75340
PHAROS:  O75340
GTEx:  ENSG00000249915 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO75340
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.252 
  • R-Value Observed: 0.254 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.266α = 90
b = 170.209β = 90
c = 46.911γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
MOLREPphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-09-08
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description