{"title":"Three Ways to Make an RNA Sequence","authors":"P. Higgs","doi":"10.1201/B22230-28","DOIUrl":"https://doi.org/10.1201/B22230-28","url":null,"abstract":"","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124569558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Evolution of Habitability","authors":"C. Lineweaver, A. Chopra, Sarah Mcintyre","doi":"10.1201/B22230-45","DOIUrl":"https://doi.org/10.1201/B22230-45","url":null,"abstract":"","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128991290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Coevolution of RNA and Peptides","authors":"P. Strazewski","doi":"10.1201/B22230-29","DOIUrl":"https://doi.org/10.1201/B22230-29","url":null,"abstract":"","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"230 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124188658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Generalized and Universalized Definition of Life Applicable to Extraterrestrial Environments","authors":"B. Clark","doi":"10.1201/B22230-7","DOIUrl":"https://doi.org/10.1201/B22230-7","url":null,"abstract":"","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124319402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Origin and Amplification of Chirality Leading to Biological Homochirality","authors":"K. Soai, A. Matsumoto, Tsuneomi Kawasaki","doi":"10.1201/B22230-23","DOIUrl":"https://doi.org/10.1201/B22230-23","url":null,"abstract":"","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"269 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134242226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Role of Cations in RNA Folding and Function","authors":"Jessica C. Bowman, A. Petrov, L. Williams","doi":"10.1201/B22230-30","DOIUrl":"https://doi.org/10.1201/B22230-30","url":null,"abstract":"Inorganic metal cations are abundant in cells and are essential to life on Earth. Metal cations are vital for a variety of biological processes. Fundamental biological processes such as electron transfer, photosynthesis, and respiration require these ions (Bertini et al. 2007). Cations stabilize transition states in the replication of DNA, transcription of DNA to RNA, and ligation and cleavage of the nucleic acids by both proteins and ribozymes (Lykke-Andersen and Christiansen 1998; Steitz 1999; Doherty and Dafforn 2000; Lee et al. 2000; Yin and Steitz 2004; Ellenberger and Tomkinson 2008). Protein sequences encoded in messenger RNA are translated by amino-acidbearing tRNAs at the ribosome, neither of which are transcribed, folded, assembled, or functional in the absence of inorganic cations. Few natural biological manipulations of the nucleic acid phosphodiester backbone proceed in vitro without divalent cations, and none are known to proceed in the absence of monovalent cations. Divalent cations stabilize three-dimensional structures of proteins, catalyze redox reactions, stabilize cell membranes, and transmit electrical current in the nervous system. Here, we focus on the interactions of metal ions with nucleic acids and explain their role in the translation system. The earliest available data suggests that translation, one of the most central processes of life, originated with dependence on inorganic cations. The catalytic center of the ribosomal large subunit (LSU), responsible for peptide bond formation, is stabilized by Mg2+. Within 20 Å of this center, about 20% of the phosphate oxygens of the RNA phosphodiester backbone interact directly with Mg2+ (Klein et al. 2004; Hsiao et al. 2009). Mg2+ bridges RNA nucleotides from disparate regions of the RNA sequence to form a structure that is inaccessible with monovalent cations alone (Hsiao and Williams 2009; Lenz et al. 2017). These Mg2+-RNA bridges are highly conserved in position and structure through all three major evolutionary branches of life, suggesting that they preceded, or at least coincided with, the last universal common ancestor (LUCA). The availability of biologically useful inorganic ions is dependent on the existence of certain minerals and on their solubility in water. The composition of the atmosphere affects cation solubility, especially partial pressures of O2(g) and CO2(g). An influx of O2(g) to an aqueous system diminishes the solubility of redox-sensitive ions such as Cu2+, Fe2+, and Mn2+. Similarly, CO2(g) decreases pH, mobilizing ions such as Ca2+ and Na+ from soils and precipitants. Fe2+ has been proposed and demonstrated to be a functional early Earth analogue for Mg2+ in nucleic-acid-processing steps, due to its similarity in size and charge density (Athavale et al. 2012; Okafor et al. 2017). Yet, in the pH range that sustains most life, Fe(aq) precipitates as Fe(OH)2(s) (Morgan and Lahav 2007) or Fe(III)(s) species (Derry 2015) in a complex mechanism and at a rate ","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129439436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Astrobiology as a Medium of Science Education","authors":"S. Kwok","doi":"10.1201/B22230-4","DOIUrl":"https://doi.org/10.1201/B22230-4","url":null,"abstract":"Astrobiology is the study of the origin, evolution, and distribution of life in the universe. Through the study of how life developed on Earth, we extrapolate this knowledge to extraterrestrial objects and speculate on how life could have developed under different conditions. Using remote observations with telescopes and direct physical experimentation with space probes, we are actively searching for evidence of life beyond the Earth.","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129715464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Formation and Delivery of Complex Organic Molecules to the Solar System and Early Earth","authors":"S. Kwok","doi":"10.1201/B22230-14","DOIUrl":"https://doi.org/10.1201/B22230-14","url":null,"abstract":"The late stages of stellar evolution from asymptotic giant branch stars to planetary nebulae are now known to be an active phase of molecular synthesis. Over 80 gas-phase molecules have been detected through rotational transitions in the mm/submm region. Infrared spectroscopy has also detected inorganic minerals, fullerenes, and organic solids. The synthesis of these molecules and solids take place over very low density ($<10^6$ cm$^{-3}$) and short ($sim10^3$ yr) time scales. The complex organics are observed to have mixed aromatic/aliphatic structures and may be related to the complex organics found in meteorites, comets, interplanetary dust particles, and planetary satellites. The possible links between stellar and solar system organics is discussed.","PeriodicalId":394692,"journal":{"name":"Handbook of Astrobiology","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132493126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
