7YSP

Tubulin heterodimer structure of GDP-2 state in solution

Summary for 7YSP

• Entry DOI: 10.2210/pdb7ysp/pdb
• EMDB information: 34079
• Descriptor: Tubulin alpha-1B chain, Tubulin beta chain, GUANOSINE-5'-TRIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: cytoskeleton, structural protein
• Biological source: Sus scrofa (pig); More
• Total number of polymer chains: 2
• Total formula weight: 101078.60

Authors

Zhou, J.,Wang, H.-W. (deposition date: 2022-08-12, release date: 2023-10-18)

Primary citation

Zhou, J.,Wang, A.,Song, Y.,Liu, N.,Wang, J.,Li, Y.,Liang, X.,Li, G.,Chu, H.,Wang, H.W.
Structural insights into the mechanism of GTP initiation of microtubule assembly.
Nat Commun, 14:5980-5980, 2023

PubMed Abstract: In eukaryotes, the dynamic assembly of microtubules (MT) plays an important role in numerous cellular processes. The underlying mechanism of GTP triggering MT assembly is still unknown. Here, we present cryo-EM structures of tubulin heterodimer at their GTP- and GDP-bound states, intermediate assembly states of GTP-tubulin, and final assembly stages of MT. Both GTP- and GDP-tubulin heterodimers adopt similar curved conformations with subtle flexibility differences. In head-to-tail oligomers of tubulin heterodimers, the inter-dimer interface of GDP-tubulin exhibits greater flexibility, particularly in tangential bending. Cryo-EM of the intermediate assembly states reveals two types of tubulin lateral contacts, "Tube-bond" and "MT-bond". Further, molecular dynamics (MD) simulations show that GTP triggers lateral contact formation in MT assembly in multiple sequential steps, gradually straightening the curved tubulin heterodimers. Therefore, we propose a flexible model of GTP-initiated MT assembly, including the formation of longitudinal and lateral contacts, to explain the nucleation and assembly of MT.

PubMed: 37749104
DOI: 10.1038/s41467-023-41615-w

Experimental method

ELECTRON MICROSCOPY (3.9 Å)