4GFA image
Entry Detail
PDB ID:
4GFA
Title:
N-terminal coiled-coil dimer of C.elegans SAS-6, crystal form A
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2012-08-03
Release Date:
2013-06-19
Method Details:
Experimental Method:
Resolution:
3.55 Å
R-Value Free:
0.35
R-Value Work:
0.30
R-Value Observed:
0.31
Space Group:
P 21 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Spindle assembly abnormal protein 6
Chain IDs:A, B, C, D
Chain Length:183
Number of Molecules:4
Biological Source:Caenorhabditis elegans
Ligand Molecules
Primary Citation
Caenorhabditis elegans centriolar protein SAS-6 forms a spiral that is consistent with imparting a ninefold symmetry.
Proc.Natl.Acad.Sci.USA 110 11373 11378 (2013)
PMID: 23798409 DOI: 10.1073/pnas.1302721110

Abstact

Centrioles are evolutionary conserved organelles that give rise to cilia and flagella as well as centrosomes. Centrioles display a characteristic ninefold symmetry imposed by the spindle assembly abnormal protein 6 (SAS-6) family. SAS-6 from Chlamydomonas reinhardtii and Danio rerio was shown to form ninefold symmetric, ring-shaped oligomers in vitro that were similar to the cartwheels observed in vivo during early steps of centriole assembly in most species. Here, we report crystallographic and EM analyses showing that, instead, Caenorhabotis elegans SAS-6 self-assembles into a spiral arrangement. Remarkably, we find that this spiral arrangement is also consistent with ninefold symmetry, suggesting that two distinct SAS-6 oligomerization architectures can direct the same output symmetry. Sequence analysis suggests that SAS-6 spirals are restricted to specific nematodes. This oligomeric arrangement may provide a structural basis for the presence of a central tube instead of a cartwheel during centriole assembly in these species.

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Primary Citation of related structures