2J3E

Dimerization is important for the GTPase activity of chloroplast translocon components atToc33 and psToc159


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Dimerization is Important for the Gtpase Activity of Chloroplast Translocon Components Attoc33 and Pstoc159.

Yeh, Y.Kesavulu, M.M.Li, H.Wu, S.Sun, Y.Konozy, E.H.E.Hsiao, C.

(2007) J Biol Chem 282: 13845

  • DOI: 10.1074/jbc.M608385200
  • Primary Citation of Related Structures:  
    2J3E

  • PubMed Abstract: 
  • Arabidopsis Toc33 (atToc33) is a GTPase and a member of the Toc (translocon at the outer-envelope membrane of chloroplasts) complex that associates with precursor proteins during protein import into chloroplasts. By inference from the crystal structu ...

    Arabidopsis Toc33 (atToc33) is a GTPase and a member of the Toc (translocon at the outer-envelope membrane of chloroplasts) complex that associates with precursor proteins during protein import into chloroplasts. By inference from the crystal structure of psToc34, a homologue in pea, the arginine at residue 130 (Arg(130)) has been implicated in the formation of the atToc33 dimer and in intermolecular GTPase activation within the dimer. Here we report the crystal structure at 3.2-A resolution of an atToc33 mutant, atToc33(R130A), in which Arg(130) was mutated to alanine. Both in solution and in crystals, atToc33(R130A) was present in its monomeric form. In contrast, both wild-type atToc33 and another pea Toc GTPase homologue, pea Toc159 (psToc159), were able to form dimers in solution. Dimeric atToc33 and psToc159 had significantly higher GTPase activity than monomeric atToc33, psToc159, and atToc33(R130A). Molecular modeling using the structures of psToc34 and atToc33(R130A) suggests that, in an architectural dimer of atToc33, Arg(130) from one monomer interacts with the beta-phosphate of GDP and several other amino acids of the other monomer. These results indicate that Arg(130) is critical for dimer formation, which is itself important for GTPase activity. Activation of GTPase activity by dimer formation is likely to be a critical regulatory step in protein import into chloroplasts.


    Organizational Affiliation

    Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, Republic of China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
T7I23.11 PROTEINA249Arabidopsis thalianaMutation(s): 1 
Gene Names: TOC33PPI1At1g02280T7I23.11
EC: 3.6.5
Find proteins for O23680 (Arabidopsis thaliana)
Explore O23680 
Go to UniProtKB:  O23680
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GDP
Query on GDP

Download CCD File 
A
GUANOSINE-5'-DIPHOSPHATE
C10 H15 N5 O11 P2
QGWNDRXFNXRZMB-UUOKFMHZSA-N
 Ligand Interaction
MG
Query on MG

Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.228 
  • R-Value Observed: 0.228 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.521α = 90
b = 71.521β = 90
c = 106.269γ = 90
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
SCALEPACKdata scaling
MOLREPphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-03-27
    Type: Initial release
  • Version 1.1: 2013-12-04
    Changes: Derived calculations, Other, Refinement description, Source and taxonomy, Structure summary, Version format compliance