1Z5W

Crystal Structure of gamma-tubulin bound to GTP

Summary for 1Z5W

• Entry DOI: 10.2210/pdb1z5w/pdb
• Related: 1Z5V
• Descriptor: Tubulin gamma-1 chain, MAGNESIUM ION, GUANOSINE-5'-TRIPHOSPHATE (3 entities in total)
• Functional Keywords: complex with gtp, structural protein
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm, cytoskeleton, centrosome: P23258
• Total number of polymer chains: 1
• Total formula weight: 54459.18

Authors

Aldaz, H.A.,Rice, L.M.,Stearns, T.,Agard, D.A. (deposition date: 2005-03-20, release date: 2005-05-31, Last modification date: 2023-08-23)

Primary citation

Aldaz, H.,Rice, L.M.,Stearns, T.,Agard, D.A.
Insights into microtubule nucleation from the crystal structure of human gamma-tubulin.
Nature, 435:523-527, 2005

PubMed Abstract: Microtubules are hollow polymers of alphabeta-tubulin that show GTP-dependent assembly dynamics and comprise a critical part of the eukaryotic cytoskeleton. Initiation of new microtubules in vivo requires gamma-tubulin, organized as an oligomer within the 2.2-MDa gamma-tubulin ring complex (gamma-TuRC) of higher eukaryotes. Structural insight is lacking regarding gamma-tubulin, its oligomerization and how it promotes microtubule assembly. Here we report the 2.7-A crystal structure of human gamma-tubulin bound to GTP-gammaS (a non-hydrolysable GTP analogue). We observe a 'curved' conformation for gamma-tubulin-GTPgammaS, similar to that seen for GDP-bound, unpolymerized alphabeta-tubulin. Tubulins are thought to represent a distinct class of GTP-binding proteins, and conformational switching in gamma-tubulin might differ from the nucleotide-dependent switching of signalling GTPases. A crystal packing interaction replicates the lateral contacts between alpha- and beta-tubulins in the microtubule, and this association probably forms the basis for gamma-tubulin oligomerization within the gamma-TuRC. Laterally associated gamma-tubulins in the gamma-TuRC might promote microtubule nucleation by providing a template that enhances the intrinsically weak lateral interaction between alphabeta-tubulin heterodimers. Because they are dimeric, alphabeta-tubulins cannot form microtubule-like lateral associations in the curved conformation. The lateral array of gamma-tubulins we observe in the crystal reveals a unique functional property of a monomeric tubulin.

PubMed: 15917813
DOI: 10.1038/nature03586

Experimental method

X-RAY DIFFRACTION (3 Å)