9eds

Tubulin cofactors D,E,G,C bound to tubulin dimer -- TBCC N terminus unbound

spinqualitylabelsall models 9eds, resolution 3.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9eds is a 7 chain structure with sequence from Escherichia coli, Saccharomyces cerevisiae and Sus scrofa. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.8Å Ligands: GDP, GTP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Microtubule polarity and dynamic polymerization arise from the self-association properties of the alphabeta-tubulin heterodimer. For decades, it has remained unclear how the tubulin cofactors TBCD, TBCE, TBCC, and the Arl2 GTPase mediate the biogenesis of alphabeta-tubulin from individual alpha- and beta-tubulins. Here, we use cryo-electron microscopy to determine structures of tubulin cofactors bound to alphabeta-tubulin. TBCD, TBCE, and Arl2 form a heterotrimeric cage-like assembly, we term TBC-DEG, around the alphabeta-tubulin heterodimer. The TBC-DEG-alphabeta-tubulin structures show that TBC-DEG wraps around beta-tubulin while TBCE extends along alpha-tubulin. The TBC-DEG/TBCC-alphabeta-tubulin structures reveal that TBCC forms multi-domain interactions with Arl2 and TBCD to engage the alphabeta-tubulin intradimer-interface, promoting TBCE rotation while TBCD holds beta-tubulin. TBCC engages the GTP-bound Arl2, multiple sites of TBCD, and the native alphabeta-tubulin intradimer interface near the alpha-tubulin N-site GTP. Together, these structures uncover transition states for alphabeta-tubulin biogenesis and degradation, suggesting a vise-like, GTP-hydrolysis-dependent mechanism in which TBCC binding to TBC-DEG modulates alphabeta-tubulin interfaces. Our studies provide structural evidence that tubulin cofactors act as enzymatic regulators that assemble the invariant alphabeta-tubulin architecture. By catalyzing alpha- and beta-tubulin biogenesis and degradation, the TBC-DEG and TBCC assemblies regulate the polymerization competency of alphabeta-tubulin for microtubule formation. Cryo-EM structures of the tubulin cofactors reveal the molecular basis of alpha/beta-tubulin biogenesis.,Taheri A, Wang Z, Singal B, Guo F, Al-Bassam J Nat Commun. 2025 Dec 29;17(1):1405. doi: 10.1038/s41467-025-68142-0. PMID:41461644 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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