View source for 9rwr


==Ancestral Fibrobacteres-Chlorobi-Bacteroidetes Group Chaperonin (AFCB) Double-Ring in Open Conformation==
<StructureSection load='9rwr' size='340' side='right'caption='[[9rwr]], [[Resolution|resolution]] 3.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9rwr]] is a 14 chain structure with sequence from [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=9RWR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9RWR 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]] 3.45&#8491;</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=9rwr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9rwr OCA], [https://pdbe.org/9rwr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9rwr RCSB], [https://www.ebi.ac.uk/pdbsum/9rwr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9rwr ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Chaperonins are essential protein-folding machines, classified into three structural and phylogenetic groups: Group I (bacterial GroEL), Group II (archaeal thermosome and eukaryotic CCT), and Group III (bacterial thermosome-like). Using ancestral sequence reconstruction (ASR) and protein resurrection, we inferred and experimentally characterized the last common ancestors of these groups (Ancestral Chaperonins ACI, ACII, and ACIII). The resurrected proteins exhibited ATPase activity (except ACII) and protected client proteins from heat-induced inactivation. Structural analyses by electron microscopy and Cryo-EM revealed that ACI forms single 7-mer rings, whereas ACII adopts a mixed population of single/double 8-mer rings, representing the first experimental observation of intermediate oligomeric states. ACII also features a unique cochaperonin-independent closure mechanism, distinct from modern Group I and II chaperonins. Together, these findings provide the experimental structural reconstruction of the most ancient and complex multimeric proteins so far, uncover novel intermediate states in chaperonin evolution, and offer a direct empirical framework for studying the emergence of multimeric complexity in early cellular life.

Ancestral Chaperonins Provide the First Structural Glimpse into Early Multimeric Protein Evolution.,Severino R, Cuellar J, Gutierrez-Seijo J, Maestro-Lopez M, Sanchez-Pulido L, Santiago C, Moreno-Paz M, Valpuesta JM, Parro V Mol Biol Evol. 2025 Nov 28:msaf314. doi: 10.1093/molbev/msaf314. PMID:41310978<ref>PMID:41310978</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Cuellar J]]
[[Category: Gutierrez-Seijo J]]
[[Category: Severino R]]