9RWP の概要
| エントリーDOI | 10.2210/pdb9rwp/pdb |
| EMDBエントリー | 54339 |
| 分子名称 | Ancestral Group II Chaperonin (ACII), ADENOSINE-5'-DIPHOSPHATE, MAGNESIUM ION (3 entities in total) |
| 機能のキーワード | chaperonins, ancestors, evolution, cryoelectron microscopy, chaperone |
| 由来する生物種 | synthetic construct |
| タンパク質・核酸の鎖数 | 16 |
| 化学式量合計 | 916206.22 |
| 構造登録者 | |
| 主引用文献 | Severino, R.,Cuellar, J.,Gutierrez-Seijo, J.,Maestro-Lopez, M.,Sanchez-Pulido, L.,Santiago, C.,Moreno-Paz, M.,Valpuesta, J.M.,Parro, V. Ancestral Chaperonins Provide the First Structural Glimpse into Early Multimeric Protein Evolution. Mol.Biol.Evol., 42:-, 2025 Cited by PubMed Abstract: 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. PubMed: 41310978DOI: 10.1093/molbev/msaf314 主引用文献が同じPDBエントリー |
| 実験手法 | ELECTRON MICROSCOPY (3.69 Å) |
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