2G13

CsoS1A with sulfate ion


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.61 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.220 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Structural Analysis of CsoS1A and the Protein Shell of the Halothiobacillus neapolitanus Carboxysome.

Tsai, Y.Sawaya, M.R.Cannon, G.C.Cai, F.Williams, E.B.Heinhorst, S.Kerfeld, C.A.Yeates, T.O.

(2007) PLoS Biol 5: e144

  • DOI: https://doi.org/10.1371/journal.pbio.0050144
  • Primary Citation of Related Structures:  
    2EWH, 2G13

  • PubMed Abstract: 

    The carboxysome is a bacterial organelle that functions to enhance the efficiency of CO2 fixation by encapsulating the enzymes ribulose bisphosphate carboxylase/oxygenase (RuBisCO) and carbonic anhydrase. The outer shell of the carboxysome is reminiscent of a viral capsid, being constructed from many copies of a few small proteins. Here we describe the structure of the shell protein CsoS1A from the chemoautotrophic bacterium Halothiobacillus neapolitanus. The CsoS1A protein forms hexameric units that pack tightly together to form a molecular layer, which is perforated by narrow pores. Sulfate ions, soaked into crystals of CsoS1A, are observed in the pores of the molecular layer, supporting the idea that the pores could be the conduit for negatively charged metabolites such as bicarbonate, which must cross the shell. The problem of diffusion across a semiporous protein shell is discussed, with the conclusion that the shell is sufficiently porous to allow adequate transport of small molecules. The molecular layer formed by CsoS1A is similar to the recently observed layers formed by cyanobacterial carboxysome shell proteins. This similarity supports the argument that the layers observed represent the natural structure of the facets of the carboxysome shell. Insights into carboxysome function are provided by comparisons of the carboxysome shell to viral capsids, and a comparison of its pores to the pores of transmembrane protein channels.


  • Organizational Affiliation

    Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Major carboxysome shell protein 1A98Halothiobacillus neapolitanusMutation(s): 0 
Gene Names: csoS1A
UniProt
Find proteins for P45689 (Halothiobacillus neapolitanus (strain ATCC 23641 / c2))
Explore P45689 
Go to UniProtKB:  P45689
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP45689
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.61 Å
  • R-Value Free: 0.260 
  • R-Value Work: 0.218 
  • R-Value Observed: 0.220 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.196α = 90
b = 66.196β = 90
c = 27.421γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
BOSdata collection

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-02-27
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Derived calculations, Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description