4BAS

Structure of the Arl6 BBS3 Small GTPase from Trypanosoma brucei with bound nucleotide analogue GppNp


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.183 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal Structure of the Small Gtpase Arl6/Bbs3 from Trypanosomabrucei.

Hemsworth, G.R.Price, H.P.Smith, D.F.Wilson, K.S.

(2013) Protein Sci. 22: 196

  • DOI: 10.1002/pro.2198

  • PubMed Abstract: 
  • Arl6/BBS3 is a small GTPase, mutations in which are implicated in the human ciliopathy Bardet-Biedl Syndrome (BBS). Arl6 is proposed to facilitate the recruitment of a large protein complex known as the BBSome to the base of the primary cilium, media ...

    Arl6/BBS3 is a small GTPase, mutations in which are implicated in the human ciliopathy Bardet-Biedl Syndrome (BBS). Arl6 is proposed to facilitate the recruitment of a large protein complex known as the BBSome to the base of the primary cilium, mediating specific trafficking of molecules to this important sensory organelle. Orthologues of Arl6 and the BBSome core subunits have been identified in the genomes of trypanosomes. Flagellum function and motility are crucial to the survival of Trypanosoma brucei, the causative agent of human African sleeping sickness, in the human bloodstream stage of its lifecycle and so the function of the BBSome proteins in trypanosomes warrants further study. RNAi knockdown of T. brucei Arl6 (TbArl6) has recently been shown to result in shortening of the trypanosome flagellum. Here we present the crystal structure of TbArl6 with the bound non-hydrolysable GTP analog GppNp at 2.0 Å resolution and highlight important differences between the trypanosomal and human proteins. Analysis of the TbArl6 active site confirms that it lacks the key glutamine that activates the nucleophile during GTP hydrolysis in other small GTPases. Furthermore, the trypanosomal proteins are significantly shorter at their N-termini suggesting a different method of membrane insertion compared to humans. Finally, analysis of sequence conservation suggests two surface patches that may be important for protein-protein interactions. Our structural analysis thus provides the basis for future biochemical characterisation of this important family of small GTPases.


    Organizational Affiliation

    Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ADP-RIBOSYLATION FACTOR, PUTATIVE (SMALL GTPASE, PUTATIVE)
A
199Trypanosoma brucei gambiense (strain MHOM/CI/86/DAL972)N/A
Find proteins for C9ZVV9 (Trypanosoma brucei gambiense (strain MHOM/CI/86/DAL972))
Go to UniProtKB:  C9ZVV9
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
MG
Query on MG

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Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
GNP
Query on GNP

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Download CCD File 
A
PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER
C10 H17 N6 O13 P3
UQABYHGXWYXDTK-UUOKFMHZSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.183 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 70.920α = 90.00
b = 70.920β = 90.00
c = 80.928γ = 120.00
Software Package:
Software NamePurpose
XDSdata reduction
MrBUMPphasing
REFMACrefinement
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-12-12
    Type: Initial release
  • Version 1.1: 2013-02-13
    Type: Database references