| Title: |
In vitro selection of ribozyme ligases that use prebiotically plausible 2-aminoimidazole-activated substrates |
| Authors: |
Walton, Travis; DasGupta, Saurja; Duzdevich, Daniel; Ohc, Seung Soo; Szostak, Jack W. |
| Contributors: |
Ohc, Seung Soo |
| Publisher Information: |
NATL ACAD SCIENCES |
| Publication Year: |
2020 |
| Collection: |
Pohang University of Science and Technology (POSTECH): Open Access System for Information Sharing (OASIS) |
| Subject Terms: |
TEMPLATE-DIRECTED SYNTHESIS; PRIMER EXTENSION; RNA POLYMERIZATION; STRUCTURAL BASIS; LIGATION; ACTIVATION; CLEAVAGE; ACCURATE; ORIGIN; TOOLS; ribozymes; prebiotic |
| Description: |
The hypothesized central role of RNA in the origin of life suggests that RNA propagation predated the advent of complex protein enzymes. A critical step of RNA replication is the template-directed synthesis of a complementary strand. Two experimental approaches have been extensively explored in the pursuit of demonstrating protein-free RNA synthesis: template-directed nonenzymatic RNA polymerization using intrinsically reactive monomers and ribozyme-catalyzed polymerization using more stable substrates such as biological 5'-triphosphates. Despite significant progress in both approaches in recent years, the assembly and copying of functional RNA sequences under prebiotic conditions remains a challenge. Here, we explore an alternative approach to RNA-templated RNA copying that combines ribozyme catalysis with RNA substrates activated with a prebiotically plausible leaving group, 2-aminoimidazole (2AI). We applied in vitro selection to identify ligase ribozymes that catalyze phosphodiester bond formation between a template-bound primer and a phosphor-imidazolide-activated oligomer. Sequencing revealed the progressive enrichment of 10 abundant sequences from a random sequence pool. Ligase activity was detected in all 10 RNA sequences; all required activation of the ligator with 2AI and generated a 3'-5' phosphodiester bond. We propose that ribozyme catalysis of phosphodiester bond formation using intrinsically reactive RNA substrates, such as imidazolides, could have been an evolutionary step connecting purely nonenzymatic to ribozyme-catalyzed RNA template copying during the origin of life. ; 1 ; 1 ; Y ; scie ; scopus |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA; Multidisciplinary Sciences; Science & Technology - Other Topics; https://oasis.postech.ac.kr/handle/2014.oak/105621; 41163; 000520011000032 |
| DOI: |
10.1073/pnas.1914367117 |
| Availability: |
https://oasis.postech.ac.kr/handle/2014.oak/105621; https://doi.org/10.1073/pnas.1914367117 |
| Accession Number: |
edsbas.5DEDF09F |
| Database: |
BASE |