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-Structure paper
タイトル | Cryo-EM structure and functional landscape of an RNA polymerase ribozyme. |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 121, Issue 3, Page e2313332121, Year 2024 |
掲載日 | 2024年1月16日 |
![]() | Ewan K S McRae / Christopher J K Wan / Emil L Kristoffersen / Kalinka Hansen / Edoardo Gianni / Isaac Gallego / Joseph F Curran / James Attwater / Philipp Holliger / Ebbe S Andersen / ![]() ![]() |
PubMed 要旨 | The emergence of an RNA replicase capable of self-replication is considered an important stage in the origin of life. RNA polymerase ribozymes (PR) - including a variant that uses trinucleotide ...The emergence of an RNA replicase capable of self-replication is considered an important stage in the origin of life. RNA polymerase ribozymes (PR) - including a variant that uses trinucleotide triphosphates (triplets) as substrates - have been created by in vitro evolution and are the closest functional analogues of the replicase, but the structural basis for their function is poorly understood. Here we use single-particle cryogenic electron microscopy (cryo-EM) and high-throughput mutation analysis to obtain the structure of a triplet polymerase ribozyme (TPR) apoenzyme and map its functional landscape. The cryo-EM structure at 5-Å resolution reveals the TPR as an RNA heterodimer comprising a catalytic subunit and a noncatalytic, auxiliary subunit, resembling the shape of a left hand with thumb and fingers at a 70° angle. The two subunits are connected by two distinct kissing-loop (KL) interactions that are essential for polymerase function. Our combined structural and functional data suggest a model for templated RNA synthesis by the TPR holoenzyme, whereby heterodimer formation and KL interactions preorganize the TPR for optimal primer-template duplex binding, triplet substrate discrimination, and templated RNA synthesis. These results provide a better understanding of TPR structure and function and should aid the engineering of more efficient PRs. |
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手法 | EM (単粒子) |
解像度 | 5.0 Å |
構造データ | EMDB-40984, PDB-8t2p: |
由来 |
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![]() | RNA / Polymerase / Ribozyme / heterodimer |