View source for 9hxc


==CryoEM structure of Asgard AtubA/B2 microtubule==
<StructureSection load='9hxc' size='340' side='right'caption='[[9hxc]], [[Resolution|resolution]] 3.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9hxc]] is a 28 chain structure with sequence from [https://en.wikipedia.org/wiki/Candidatus_Lokiarchaeum_ossiferum Candidatus Lokiarchaeum ossiferum]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9HXC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9HXC FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=9hxc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9hxc OCA], [https://pdbe.org/9hxc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9hxc RCSB], [https://www.ebi.ac.uk/pdbsum/9hxc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9hxc ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Microtubules are a hallmark of eukaryotes. Archaeal and bacterial homologs of tubulins typically form homopolymers and non-tubular superstructures. The origin of heterodimeric tubulins assembling into microtubules remains unclear. Here, we report the discovery of microtubule-forming tubulins in Asgard archaea, the closest known relatives of eukaryotes. These Asgard tubulins (AtubA/B) are closely related to eukaryotic alpha/beta-tubulins and the enigmatic bacterial tubulins BtubA/B. Proteomics of Candidatus Lokiarchaeum ossiferum showed that AtubA/B were highly expressed. Cryoelectron microscopy structures demonstrate that AtubA/B form eukaryote-like heterodimers, which assembled into 5-protofilament bona fide microtubules in vitro. The additional paralog AtubB2 lacks a nucleotide-binding site and competitively displaced AtubB. These AtubA/B2 heterodimers polymerized into 7-protofilament non-canonical microtubules. In a sub-population of Ca. Lokiarchaeum ossiferum cells, cryo-tomography revealed tubular structures, while expansion microscopy identified AtubA/B cytoskeletal assemblies. Our findings suggest a pre-eukaryotic origin of microtubules and provide a framework for understanding the fundamental principles of microtubule assembly.

Microtubules in Asgard archaea.,Wollweber F, Xu J, Ponce-Toledo RI, Marxer F, Rodrigues-Oliveira T, Possnecker A, Luo ZH, Malit JJL, Kokhanovska A, Wieczorek M, Schleper C, Pilhofer M Cell. 2025 Mar 19:S0092-8674(25)00254-5. doi: 10.1016/j.cell.2025.02.027. PMID:40120574<ref>PMID:40120574</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9hxc" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Candidatus Lokiarchaeum ossiferum]]
[[Category: Large Structures]]
[[Category: Kokhanovska A]]
[[Category: Malit JJL]]
[[Category: Pilhofer M]]
[[Category: Ponce-Toledo RI]]
[[Category: Rodrigues-Oliveira T]]
[[Category: Schleper C]]
[[Category: Wieczorek M]]
[[Category: Wollweber F]]
[[Category: Xu J]]