24SV
Averaged protofilament of Heimdallarchaeales alpha/beta tubulin microtubule with a single seam
Summary for 24SV
| Entry DOI | 10.2210/pdb24sv/pdb |
| EMDB information | 69786 69801 |
| Descriptor | Heim-alpha-tubulin, Heim-beta-tubulin, GUANOSINE-5'-DIPHOSPHATE, ... (4 entities in total) |
| Functional Keywords | heimdallarchaea tubulin microtubule archaea, protein fibril |
| Biological source | Candidatus Heimdallarchaeaceae More |
| Total number of polymer chains | 4 |
| Total formula weight | 191061.15 |
| Authors | Tran, L.T.,Ali, S.,Matsumoto, T.,Yamazaki, Y.,Narita, A.,Miyazaki, M.,Robinson, R.C. (deposition date: 2026-03-19, release date: 2026-06-24, Last modification date: 2026-08-05) |
| Primary citation | Tran, L.T.,Ali, S.,Matsumoto, T.,Yamazaki, Y.,Narita, A.,Miyazaki, M.,Robinson, R.C. Structure and dynamics of a four-protofilament microtubule from Heimdallarchaeales alpha / beta-tubulin. Sci Adv, 12:eaeh4305-eaeh4305, 2026 Cited by PubMed Abstract: Eukaryotic microtubules are typically 13-protofilament tubes assembled from α/β-tubulin heterodimers that combine mechanical rigidity with dynamic instability. Homologous tubulins have been identified in Asgard archaea, the closest prokaryotic relatives to eukaryotes. Here, we characterize a heterodimeric α/β-tubulin system from Heimdallarchaeales. Biochemical reconstitution shows that α/β-tubulin forms a heterodimer that undergoes guanosine 5'-triphosphate-dependent polymerization with coupled nucleotide hydrolysis. Cryo-electron microscopy reveals that the polymers are composed of four-protofilament tubules, with microtubule-like lattices formed by conserved longitudinal interfaces and ball-and-socket lateral contacts. Single-filament imaging demonstrates intrinsic kinetic polarity and dynamic instability, while liposome encapsulation shows that microtubule growth generates forces sufficient to deform membranes. Despite their reduced protofilament number, -α/β-microtubules share key structural and dynamic features with eukaryotic microtubules but exhibit lower bending stiffness and polymerization force. Thus, microtubule-like polymers can form from a range of protofilament numbers, with reduced architectures potentially adapted to small cellular dimensions and lower mechanical loads. Together, our results indicate expansion in microtubule protofilament number during eukaryogenesis. PubMed: 42455893DOI: 10.1126/sciadv.aeh4305 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.4 Å) |
Structure validation
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