1
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Kakoti A, Joyce GF. RNA Polymerase Ribozyme That Recognizes the Template-Primer Complex through Tertiary Interactions. Biochemistry 2023. [PMID: 37256719 DOI: 10.1021/acs.biochem.3c00091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
RNA enzymes (ribozymes) often rely on specific base-pairing interactions to engage RNA substrates, which limits the substrate sequence generality of these enzymes. An RNA polymerase ribozyme that was previously optimized by directed evolution to operate in a more efficient and sequence-general manner can now recognize the RNA template, RNA primer, and incoming nucleoside 5'-triphosphate (NTP) entirely through tertiary interactions. As with proteinaceous polymerases, these tertiary interactions are largely agnostic to the sequence of the template, which is an essential property for the unconstrained transmission of genetic information. The polymerase ribozyme exhibits Michaelis-Menten saturation kinetics, with a catalytic rate of 0.1-1 min-1 and a Km of 0.1-1 μM. Earlier forms of the polymerase did not exhibit a saturable substrate binding site, but this property emerged over the course of directed evolution as the ribozyme underwent a structural rearrangement of its catalytic center. The optimized polymerase makes tertiary contacts with both the template and primer, including a critical interaction at the C2' position of the template nucleotide that opposes the 3'-terminal nucleotide of the primer. UV cross-linking studies paint a picture of how several portions of the ribozyme, including regions that were remodeled by directed evolution, come together to position the template, primer, and NTP within the active site for RNA polymerization.
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Affiliation(s)
- Ankana Kakoti
- The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Gerald F Joyce
- The Salk Institute, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
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2
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Cojocaru R, Unrau PJ. Processive RNA polymerization and promoter recognition in an RNA World. Science 2021; 371:1225-1232. [PMID: 33737482 DOI: 10.1126/science.abd9191] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 02/04/2021] [Indexed: 12/21/2022]
Abstract
Early life is thought to have required the self-replication of RNA by RNA replicases. However, how such replicases evolved and subsequently enabled gene expression remains largely unexplored. We engineered and selected a holopolymerase ribozyme that uses a sigma factor-like specificity primer to first recognize an RNA promoter sequence and then, in a second step, rearrange to a processive elongation form. Using its own sequence, the polymerase can also program itself to polymerize from certain RNA promoters and not others. This selective promoter-based polymerization could allow an RNA replicase ribozyme to define "self" from "nonself," an important development for the avoidance of replicative parasites. Moreover, the clamp-like mechanism of this polymerase could eventually enable strand invasion, a critical requirement for replication in the early evolution of life.
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Affiliation(s)
- Razvan Cojocaru
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
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3
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Setterholm NA, Haratipour P, Kashemirov BA, McKenna CE, Joyce GF. Kinetic Effects of β,γ-Modified Deoxynucleoside 5'-Triphosphate Analogues on RNA-Catalyzed Polymerization of DNA. Biochemistry 2020; 60:1-5. [PMID: 33356161 DOI: 10.1021/acs.biochem.0c00779] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A recently described DNA polymerase ribozyme, obtained by in vitro evolution, provides the opportunity to investigate mechanistic features of RNA catalysis using methods that previously had only been applied to DNA polymerase proteins. Insight can be gained into the transition state of the DNA polymerization reaction by studying the behavior of various β,γ-bridging substituted methylene (CXY; X, Y = H, halo, methyl) or imido (NH) dNTP analogues that differ with regard to the pKa4 of the bisphosphonate or imidodiphosphate leaving group. The apparent rate constant (kpol) of the polymerase ribozyme was determined for analogues of dGTP and dCTP that span a broad range of acidities for the leaving group, ranging from 7.8 for the CF2-bisphosphonate to 11.6 for the CHCH3-bisphosphonate. A Brønsted plot of log(kpol) versus pKa4 of the leaving group demonstrates linear free energy relationships (LFERs) for dihalo-, monohalo-, and non-halogen-substituted analogues of the dNTPs, with negative slopes, as has been observed for DNA polymerase proteins. The unsubstituted dNTPs have a faster catalytic rate than would be predicted from consideration of the linear free energy relationship alone, presumably due to a relatively more favorable interaction of the β,γ-bridging oxygen within the active site. Although the DNA polymerase ribozyme is considerably slower than DNA polymerase proteins, it exhibits a similar LFER fingerprint, suggesting mechanistic commonality pertaining to the buildup of negative charge in the transition state, despite the very different chemical compositions of the two catalysts.
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Affiliation(s)
- Noah A Setterholm
- The Salk Institute, Jack H. Skirball Center for Chemical Biology and Proteomics, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Pouya Haratipour
- Department of Chemistry, Dana and David Dornsife College of Letters, Arts, and Sciences, University of Southern California, University Park Campus, Los Angeles, California 90089, United States
| | - Boris A Kashemirov
- Department of Chemistry, Dana and David Dornsife College of Letters, Arts, and Sciences, University of Southern California, University Park Campus, Los Angeles, California 90089, United States
| | - Charles E McKenna
- Department of Chemistry, Dana and David Dornsife College of Letters, Arts, and Sciences, University of Southern California, University Park Campus, Los Angeles, California 90089, United States
| | - Gerald F Joyce
- The Salk Institute, Jack H. Skirball Center for Chemical Biology and Proteomics, 10010 North Torrey Pines Road, La Jolla, California 92037, United States
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4
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Tjhung KF, Shokhirev MN, Horning DP, Joyce GF. An RNA polymerase ribozyme that synthesizes its own ancestor. Proc Natl Acad Sci U S A 2020; 117:2906-2913. [PMID: 31988127 PMCID: PMC7022166 DOI: 10.1073/pnas.1914282117] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The RNA-based organisms from which modern life is thought to have descended would have depended on an RNA polymerase ribozyme to copy functional RNA molecules, including copying the polymerase itself. Such a polymerase must have been capable of copying structured RNAs with high efficiency and high fidelity to maintain genetic information across successive generations. Here the class I RNA polymerase ribozyme was evolved in vitro for the ability to synthesize functional ribozymes, resulting in the markedly improved ability to synthesize complex RNAs using nucleoside 5'-triphosphate (NTP) substrates. The polymerase is descended from the class I ligase, which contains the same catalytic core as the polymerase. The class I ligase can be synthesized by the improved polymerase as three separate RNA strands that assemble to form a functional ligase. The polymerase also can synthesize the complement of each of these three strands. Despite this remarkable level of activity, only a very small fraction of the assembled ligases retain catalytic activity due to the presence of disabling mutations. Thus, the fidelity of RNA polymerization should be considered a major impediment to the construction of a self-sustained, RNA-based evolving system. The propagation of heritable information requires both efficient and accurate synthesis of genetic molecules, a requirement relevant to both laboratory systems and the early history of life on Earth.
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Affiliation(s)
- Katrina F Tjhung
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute, La Jolla, CA 92037
| | - Maxim N Shokhirev
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute, La Jolla, CA 92037
| | - David P Horning
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute, La Jolla, CA 92037
| | - Gerald F Joyce
- Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute, La Jolla, CA 92037
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5
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Janzen E, Blanco C, Peng H, Kenchel J, Chen IA. Promiscuous Ribozymes and Their Proposed Role in Prebiotic Evolution. Chem Rev 2020; 120:4879-4897. [PMID: 32011135 PMCID: PMC7291351 DOI: 10.1021/acs.chemrev.9b00620] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
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The ability of enzymes,
including ribozymes, to catalyze side reactions
is believed to be essential to the evolution of novel biochemical
activities. It has been speculated that the earliest ribozymes, whose
emergence marked the origin of life, were low in activity but high
in promiscuity, and that these early ribozymes gave rise to specialized
descendants with higher activity and specificity. Here, we review
the concepts related to promiscuity and examine several cases of highly
promiscuous ribozymes. We consider the evidence bearing on the question
of whether de novo ribozymes would be quantitatively
more promiscuous than later evolved ribozymes or protein enzymes.
We suggest that while de novo ribozymes appear to
be promiscuous in general, they are not obviously more promiscuous
than more highly evolved or active sequences. Promiscuity is a trait
whose value would depend on selective pressures, even during prebiotic
evolution.
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Affiliation(s)
- Evan Janzen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93109, United States.,Biomolecular Sciences and Engineering Program, University of California, Santa Barbara, Santa Barbara, California 93109, United States
| | - Celia Blanco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93109, United States
| | - Huan Peng
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93109, United States
| | - Josh Kenchel
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93109, United States.,Biomolecular Sciences and Engineering Program, University of California, Santa Barbara, Santa Barbara, California 93109, United States
| | - Irene A Chen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93109, United States.,Biomolecular Sciences and Engineering Program, University of California, Santa Barbara, Santa Barbara, California 93109, United States.,Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California 90095, United States
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6
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Akoopie A, Müller UF. The NTP binding site of the polymerase ribozyme. Nucleic Acids Res 2019; 46:10589-10597. [PMID: 30289487 PMCID: PMC6237761 DOI: 10.1093/nar/gky898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 10/03/2018] [Indexed: 11/15/2022] Open
Abstract
A previously developed RNA polymerase ribozyme uses nucleoside triphosphates (NTPs) to extend a primer 3′-terminus, templated by an RNA template with good fidelity, forming 3′-5′-phosphordiester bonds. Indirect evidence has suggested that the ribozyme's accessory domain binds the NTP with a highly conserved purine-rich loop. To determine the NTP binding site more precisely we evolved the ribozyme for efficient use of 6-thio guanosine triphosphate (6sGTP). 6sGTP never appeared in the evolutionary history of the ribozyme, therefore it was expected that mutations would appear at the NTP binding site, adapting to more efficient binding of 6sGTP. Indeed, the evolution identified three mutations that mediate 200-fold improved incorporation kinetics for 6sGTP. A >50-fold effect resulted from mutation A156U in the purine-rich loop, identifying the NTP binding site. This mutation acted weakly cooperative with two other beneficial mutations, C113U in the P2 stem near the catalytic site, and C79U on the surface of the catalytic domain. The preference pattern of the ribozyme for different NTPs changed when position 156 was mutated, confirming a direct contact between position 156 and the NTP. The results suggest that A156 stabilizes the NTP in the active site by a hydrogen bond to the Hoogsteen face of the NTP.
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Affiliation(s)
- Arvin Akoopie
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Ulrich F Müller
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
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7
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Abstract
Central to the “RNA world” hypothesis of the origin of life is the emergence of an RNA catalyst capable of RNA replication. However, possible replicase ribozymes are quite complex and were likely predated by simpler non-enzymatic replication reactions. The templated polymerisation of phosphorimidazolide (Imp) activated ribonucleotides currently appears as the most tractable route to both generate and replicate short RNA oligomer pools from which a replicase could emerge. Herein we demonstrate the rapid assembly of complex ribozymes from such Imp-activated RNA fragment pools. Specifically, we show assembly of a newly selected minimal RNA polymerase ribozyme variant (150 nt) by RNA templated ligation of 5’-2-methylimidazole-activated RNA oligomers <30 nucleotides long. Our results provide support for the possibility that complex RNA structures could have emerged from pools of activated RNA oligomers and outlines a path for the transition from non-enzymatic/chemical to enzymatic RNA replication.
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Affiliation(s)
- Falk Wachowius
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH (UK)
| | - Philipp Holliger
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH (UK)
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8
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Chaput JC. Visualizing primer extension without enzymes. eLife 2018; 7:e37926. [PMID: 29851382 PMCID: PMC5980227 DOI: 10.7554/elife.37926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 05/25/2018] [Indexed: 12/02/2022] Open
Abstract
X-ray crystallography has been used to observe the synthesis of RNA in the absence of enzymes with atomic resolution.
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Affiliation(s)
- John C Chaput
- Department of Pharmaceutical SciencesUniversity of California, IrvineIrvineUnited States
- Department of ChemistryUniversity of California, IrvineIrvineUnited States
- Department of Molecular Biology & BiochemistryUniversity of California, IrvineIrvineUnited States
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9
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Cojocaru R, Unrau PJ. Transitioning to DNA genomes in an RNA world. eLife 2017; 6. [PMID: 29091027 PMCID: PMC5665642 DOI: 10.7554/elife.32330] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 10/27/2017] [Indexed: 11/25/2022] Open
Abstract
The unexpected ability of an RNA polymerase ribozyme to copy RNA into DNA has ramifications for understanding how DNA genomes evolved.
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Affiliation(s)
- Razvan Cojocaru
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada
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10
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Tagami S, Attwater J, Holliger P. Simple peptides derived from the ribosomal core potentiate RNA polymerase ribozyme function. Nat Chem 2017; 9:325-332. [PMID: 28338682 DOI: 10.1038/nchem.2739] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 01/20/2017] [Indexed: 11/09/2022]
Abstract
The emergence of functional interactions between nucleic acids and polypeptides was a key transition in the origin of life and remains at the heart of all biology. However, how and why simple non-coded peptides could have become critical for RNA function is unclear. Here, we show that putative ancient peptide segments from the cores of both ribosomal subunits enhance RNA polymerase ribozyme (RPR) function, as do derived homopolymeric peptides comprising lysine or the non-proteinogenic lysine analogues ornithine or, to a lesser extent, diaminobutyric acid, irrespective of chirality or chiral purity. Lysine decapeptides enhance RPR function by promoting holoenzyme assembly through primer-template docking, accelerate RPR evolution, and allow RPR-catalysed RNA synthesis at near physiological (≥1 mM) Mg2+ concentrations, enabling templated RNA synthesis within membranous protocells. Our results outline how compositionally simple, mixed-chirality peptides may have augmented the functional potential of early RNAs and promoted the emergence of the first protocells.
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Affiliation(s)
- Shunsuke Tagami
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - James Attwater
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Philipp Holliger
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
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11
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Abstract
In all extant life, genetic information is stored in nucleic acids that are replicated by polymerase proteins. In the hypothesized RNA world, before the evolution of genetically encoded proteins, ancestral organisms contained RNA genes that were replicated by an RNA polymerase ribozyme. In an effort toward reconstructing RNA-based life in the laboratory, in vitro evolution was used to improve dramatically the activity and generality of an RNA polymerase ribozyme by selecting variants that can synthesize functional RNA molecules from an RNA template. The improved polymerase ribozyme is able to synthesize a variety of complex structured RNAs, including aptamers, ribozymes, and, in low yield, even tRNA. Furthermore, the polymerase can replicate nucleic acids, amplifying short RNA templates by more than 10,000-fold in an RNA-catalyzed form of the PCR. Thus, the two prerequisites of Darwinian life-the replication of genetic information and its conversion into functional molecules-can now be accomplished with RNA in the complete absence of proteins.
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12
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Martin LL, Unrau PJ, Müller UF. RNA synthesis by in vitro selected ribozymes for recreating an RNA world. Life (Basel) 2015; 5:247-68. [PMID: 25610978 PMCID: PMC4390851 DOI: 10.3390/life5010247] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/22/2014] [Accepted: 01/13/2015] [Indexed: 01/20/2023] Open
Abstract
The RNA world hypothesis states that during an early stage of life, RNA molecules functioned as genome and as the only genome-encoded catalyst. This hypothesis is supported by several lines of evidence, one of which is the in vitro selection of catalytic RNAs (ribozymes) in the laboratory for a wide range of reactions that might have been used by RNA world organisms. This review focuses on three types of ribozymes that could have been involved in the synthesis of RNA, the core activity in the self-replication of RNA world organisms. These ribozyme classes catalyze nucleoside synthesis, triphosphorylation, and the polymerization of nucleoside triphosphates. The strengths and weaknesses regarding each ribozyme’s possible function in a self-replicating RNA network are described, together with the obstacles that need to be overcome before an RNA world organism can be generated in the laboratory.
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Affiliation(s)
- Lyssa L Martin
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
| | - Ulrich F Müller
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0356, USA.
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13
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Abstract
The complexity of even the simplest known life forms makes efforts to synthesize living cells from inanimate components seem like a daunting task. However, recent progress toward the creation of synthetic cells, ranging from simple protocells to artificial cells approaching the complexity of bacteria, suggests that the synthesis of life is now a realistic goal. Protocell research, fueled by advances in the biophysics of primitive membranes and the chemistry of nucleic acid replication, is providing new insights into the origin of cellular life. Parallel efforts to construct more complex artificial cells, incorporating translational machinery and protein enzymes, are providing information about the requirements for protein-based life. We discuss recent advances and remaining challenges in the synthesis of artificial cells, the possibility of creating new forms of life distinct from existing biology, and the promise of this research for gaining a deeper understanding of the nature of living systems.
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Affiliation(s)
- J Craig Blain
- Howard Hughes Medical Institute, Department of Molecular Biology, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston, Massachusetts 02114; ,
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14
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Yao C, Müller UF. Polymerase ribozyme efficiency increased by G/T-rich DNA oligonucleotides. RNA (NEW YORK, N.Y.) 2011; 17:1274-1281. [PMID: 21622900 PMCID: PMC3138564 DOI: 10.1261/rna.2726811] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 04/25/2011] [Indexed: 05/30/2023]
Abstract
The RNA world hypothesis states that the early evolution of life went through a stage where RNA served as genome and as catalyst. The replication of RNA world organisms would have been facilitated by ribozymes that catalyze RNA polymerization. To recapitulate an RNA world in the laboratory, a series of RNA polymerase ribozymes was developed previously. However, these ribozymes have a polymerization efficiency that is too low for self-replication, and the most efficient ribozymes prefer one specific template sequence. The limiting factor for polymerization efficiency is the weak sequence-independent binding to its primer/template substrate. Most of the known polymerase ribozymes bind an RNA heptanucleotide to form the P2 duplex on the ribozyme. By modifying this heptanucleotide, we were able to significantly increase polymerization efficiency. Truncations at the 3'-terminus of this heptanucleotide increased full-length primer extension by 10-fold, on a specific template sequence. In contrast, polymerization on several different template sequences was improved dramatically by replacing the RNA heptanucleotide with DNA oligomers containing randomized sequences of 15 nt. The presence of G and T in the random sequences was sufficient for this effect, with an optimal composition of 60% G and 40% T. Our results indicate that these DNA sequences function by establishing many weak and nonspecific base-pairing interactions to the single-stranded portion of the template. Such low-specificity interactions could have had important functions in an RNA world.
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Affiliation(s)
- Chengguo Yao
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
| | - Ulrich F. Müller
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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15
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Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
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16
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Wochner A, Attwater J, Coulson A, Holliger P. Ribozyme-catalyzed transcription of an active ribozyme. Science 2011; 332:209-12. [PMID: 21474753 DOI: 10.1126/science.1200752] [Citation(s) in RCA: 262] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A critical event in the origin of life is thought to have been the emergence of an RNA molecule capable of replicating a primordial RNA "genome." Here we describe the evolution and engineering of an RNA polymerase ribozyme capable of synthesizing RNAs of up to 95 nucleotides in length. To overcome its sequence dependence, we recombined traits evolved separately in different ribozyme lineages. This yielded a more general polymerase ribozyme that was able to synthesize a wider spectrum of RNA sequences, as we demonstrate by the accurate synthesis of an enzymatically active RNA, a hammerhead endonuclease ribozyme. This recapitulates a central aspect of an RNA-based genetic system: the RNA-catalyzed synthesis of an active ribozyme from an RNA template.
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Affiliation(s)
- Aniela Wochner
- Medical Research Council (MRC) Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
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