{"title":"原始RNA世界中的RNA i-Motif。","authors":"Bin Wang","doi":"10.1007/s11084-019-09576-7","DOIUrl":null,"url":null,"abstract":"<p><p>The primordial RNA world is a hypothetical era prior to the appearance of protein and DNA, when RNA molecules were the sole building blocks for early forms of life on Earth. A critical concern with the RNA-world hypothesis is the instability of the cytosine nucleobase compared to the other three bases (adenine, guanine, and uracil). The author proposes that cytosine residues could have stably existed in the primordial world in the RNA i-motif, a four-stranded quadruplex structure formed by base-pairing of protonated and unprotonated cytosine residues under acidic conditions. The i-motif structure not only increases the lifetime of cytosine residues by slowing their deamination rate, but could also allow RNA polymers to bind to certain ligands (e.g., anions) to perform critical functions. Future studies focused on determining the rate of cytosine deamination in RNA i-motifs over a range of pH, temperature, and pressure conditions, and on interrogating the interactions between ligands and RNA i-motifs, could uncover new evidence of the origin of life on Earth.</p>","PeriodicalId":19614,"journal":{"name":"Origins of Life and Evolution of Biospheres","volume":"49 1-2","pages":"105-109"},"PeriodicalIF":1.9000,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s11084-019-09576-7","citationCount":"1","resultStr":"{\"title\":\"The RNA i-Motif in the Primordial RNA World.\",\"authors\":\"Bin Wang\",\"doi\":\"10.1007/s11084-019-09576-7\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>The primordial RNA world is a hypothetical era prior to the appearance of protein and DNA, when RNA molecules were the sole building blocks for early forms of life on Earth. A critical concern with the RNA-world hypothesis is the instability of the cytosine nucleobase compared to the other three bases (adenine, guanine, and uracil). The author proposes that cytosine residues could have stably existed in the primordial world in the RNA i-motif, a four-stranded quadruplex structure formed by base-pairing of protonated and unprotonated cytosine residues under acidic conditions. The i-motif structure not only increases the lifetime of cytosine residues by slowing their deamination rate, but could also allow RNA polymers to bind to certain ligands (e.g., anions) to perform critical functions. Future studies focused on determining the rate of cytosine deamination in RNA i-motifs over a range of pH, temperature, and pressure conditions, and on interrogating the interactions between ligands and RNA i-motifs, could uncover new evidence of the origin of life on Earth.</p>\",\"PeriodicalId\":19614,\"journal\":{\"name\":\"Origins of Life and Evolution of Biospheres\",\"volume\":\"49 1-2\",\"pages\":\"105-109\"},\"PeriodicalIF\":1.9000,\"publicationDate\":\"2019-06-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1007/s11084-019-09576-7\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Origins of Life and Evolution of Biospheres\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1007/s11084-019-09576-7\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2019/5/25 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q2\",\"JCRName\":\"BIOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Origins of Life and Evolution of Biospheres","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1007/s11084-019-09576-7","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2019/5/25 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"BIOLOGY","Score":null,"Total":0}
The primordial RNA world is a hypothetical era prior to the appearance of protein and DNA, when RNA molecules were the sole building blocks for early forms of life on Earth. A critical concern with the RNA-world hypothesis is the instability of the cytosine nucleobase compared to the other three bases (adenine, guanine, and uracil). The author proposes that cytosine residues could have stably existed in the primordial world in the RNA i-motif, a four-stranded quadruplex structure formed by base-pairing of protonated and unprotonated cytosine residues under acidic conditions. The i-motif structure not only increases the lifetime of cytosine residues by slowing their deamination rate, but could also allow RNA polymers to bind to certain ligands (e.g., anions) to perform critical functions. Future studies focused on determining the rate of cytosine deamination in RNA i-motifs over a range of pH, temperature, and pressure conditions, and on interrogating the interactions between ligands and RNA i-motifs, could uncover new evidence of the origin of life on Earth.
期刊介绍:
The subject of the origin and early evolution of life is an inseparable part of the general discipline of Astrobiology. The journal Origins of Life and Evolution of Biospheres places special importance on the interconnection as well as the interdisciplinary nature of these fields, as is reflected in its subject coverage. While any scientific study which contributes to our understanding of the origins, evolution and distribution of life in the Universe is suitable for inclusion in the journal, some examples of important areas of interest are: prebiotic chemistry and the nature of Earth''s early environment, self-replicating and self-organizing systems, the theory of the RNA world and of other possible precursor systems, and the problem of the origin of the genetic code. Early evolution of life - as revealed by such techniques as the elucidation of biochemical pathways, molecular phylogeny, the study of Precambrian sediments and fossils and of major innovations in microbial evolution - forms a second focus. As a larger and more general context for these areas, Astrobiology refers to the origin and evolution of life in a cosmic setting, and includes interstellar chemistry, planetary atmospheres and habitable zones, the organic chemistry of comets, meteorites, asteroids and other small bodies, biological adaptation to extreme environments, life detection and related areas. Experimental papers, theoretical articles and authorative literature reviews are all appropriate forms for submission to the journal. In the coming years, Astrobiology will play an even greater role in defining the journal''s coverage and keeping Origins of Life and Evolution of Biospheres well-placed in this growing interdisciplinary field.