Nucleobases are the informational subunits of RNA and DNA and are essential to all known forms of life. The nucleobases can be divided into two groups of molecules: the pyrimidine-based compounds that include uracil, cytosine, and thymine, and the purine-based compounds that include adenine and guanine. Previous work in our laboratory has demonstrated that uracil, cytosine, thymine, and other nonbiological, less common nucleobases can form abiotically from the UV photoirradiation of pyrimidine in simple astrophysical ice analogues containing combinations of H2O, NH3, and CH4. In this work, we focused on the UV photoirradiation of purine mixed with combinations of H2O and NH3 ices to determine whether or not the full complement of biological nucleobases can be formed abiotically under astrophysical conditions. Room-temperature analyses of the resulting photoproducts resulted in the detection of adenine, guanine, and numerous other functionalized purine derivatives. Key Words: Pyrimidine—Nucleobases—Interstellar; Ices—Cometary; Ices—Molecular processes—Prebiotic chemistry. Astrobiology 17, 761–770.
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References
1.
AllamandolaL.J., SandfordS.A., and ValeroG.J. (1988) Photochemical and thermal evolution of interstellar/precometary ice analogs. Icarus, 76:225–252.
2.
BennettC.J. and KaiserR.I. (2007) On the formation of glycolaldehyde (HCOCH2OH) and methyl formate (HCOOCH3) in interstellar ice analogs. Astrophys J, 600:1289–1295.
3.
BeraP.P., NuevoM., MilamS.N., SandfordS.A., and LeeT.J. (2010) Mechanism for the abiotic synthesis of uracil via UV-induced oxidation of pyrimidine in pure H2O ices under astrophysical conditions. J Chem Phys, 133:104303.
4.
BeraP.P., NuevoM., MatereseC.K., LeeT.J., and SandfordS.A. (2016) Mechanisms for the formation of thymine under astrophysical conditions and implications for the origin of life. J Chem Phys, 144, doi:10.1063/1.4945745.
5.
BeraP.P., SteinT., Head-GordonM., and LeeT.J. (2017) Mechanisms of the formation of adenine, guanine, and their analogues in UV-irradiated mixed NH3:H2O molecular ices containing purine. Astrobiology, 17, doi:10.1089/ast.2016.1614.
6.
BernsteinM.P., SandfordS.A., AllamandolaL.J., and ChangS. (1995) Organic compounds produced by photolysis of realistic interstellar and cometary ice analogs containing methanol. Astrophys J, 454:327–344.
7.
BernsteinM.P., SandfordS.A., AllamandolaL.J., GilletteJ.S., ClemettS.J., and ZareR.N. (1999) UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers. Science, 283:1135–1138.
8.
BernsteinM.P., DworkinJ.P., SandfordS.A., CooperG.W., and AllamandolaL.J. (2002a) The formation of racemic amino acids by ultraviolet photolysis of interstellar ice analogs. Nature, 416:401–403.
9.
BernsteinM.P., ElsilaJ.E., DworkinJ.P., SandfordS.A., AllamandolaL.J., and ZareR.N. (2002b) Side group addition to the PAH coronene by UV photolysis in cosmic ice analogs. Astrophys J, 576:1115–1120.
10.
BrünkenS., McCarthyM.C., ThaddeusP., GodfreyP.D., and BrownR.D. (2006) Improved line frequencies for the nucleic acid base uracil for a radioastronomical search. Astron Astrophys, 459:317–320.
11.
CaffertyB.J. and HudN.V. (2015) Was a pyrimidine-pyrimidine base pair the ancestor of Watson-Crick base pairs? Insights from a systematic approach to the origin of RNA. Isr J Chem, 55:891–905.
12.
CallahanM.P., SmithK.E., CleavesH.J.II, RuzickaJ., SternJ.C., GlavinD.P., HouseC.H., and DworkinJ.P. (2011) Carbonaceous meteorites contain a wide range of extraterrestrial nucleobases. Proc Natl Acad Sci USA, 108:13995–13998.
13.
CallahanM.P., GerakinesP.A., MartinM.G., PeetersZ., and HudsonR.L. (2013) Irradiated benzene ice provides clues to meteoritic organic chemistry. Icarus, 226:1201–1209.
14.
CharnleyS.B., KuanY.-J., HuangH.-C., BottaO., ButnerH.M., CoxN., DespoisD., EhrenfreundP., KisielZ., LeeY.-Y., MarkwickA.J., PeetersZ., and RodgersS.D. (2005) Astronomical searches for nitrogen heterocycles. Adv Space Res, 36:137–145.
15.
CherchneffI., BarkerJ.R., and TielensA.G.G.M. (1992) Polycyclic aromatic hydrocarbon formation in carbon-rich stellar envelopes. Astrophys J, 401:269–287.
16.
CieslaF.J. and SandfordS.A. (2012) Organic synthesis via irradiation and warming of ice grains in the solar nebula. Science, 336:452–454.
17.
CrickF.H.C. (1968) The origin of genetic code. J Mol Biol, 38:367–379.
18.
DworkinJ.P., DeamerD.W., SandfordS.A., and AllamandolaL.J. (2001) Self-assembling amphiphilic molecules: synthesis in simulated interstellar/precometary ices. Proc Natl Acad Sci USA, 98:815–819.
19.
FolsomeC.E., LawlessJ., RomiezM., and PonnamperumaC. (1971) Heterocyclic compounds indigenous to the Murchison meteorite. Nature, 232:108–109.
20.
FrenklachM. and FeigelsonE.D. (1989) Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes. Astrophys J, 341:372–384.
21.
GerakinesP.A., MooreM.H., and HudsonR.L. (2001) Energetic processing of laboratory ice analogs: UV photolysis versus ion bombardment. J Geophys Res, 106:33381–33385.
22.
HagenW., AllamandolaL.J., and GreenbergM. (1979) Interstellar molecule formation in grain mantles: the laboratory analog experiments, results implications. Astrophys Space Sci, 65:215–240.
23.
HamidA.M., BeraP.P., LeeT.J., AzizS.G., AlyoubiA.O., and El-ShallM.S. (2014) Evidence for the formation of pyrimidine cations from the sequential reactions of hydrogen cyanide with the acetylene radical cation. J Phys Chem Lett, 5:3392–3398.
HayatsuR., AndersE., StudierM.H., and MooreL.P. (1975) Purines and triazines in the Murchison meteorite. Geochim Cosmochim Acta, 39:471–488.
26.
KuanY.-J., CharnleyS.B., HuangH.-C., KisielZ., EhrenfreundP., TsengW.-L., and YanC.-H. (2004) Searches for interstellar molecules of potential prebiotic importance. Adv Space Res, 33:31–39.
27.
MartinsZ., BottaO., FogelM.L., SephtonM.A., GlavinD.P., WatsonJ.S., DworkinJ.P., SchwartzA.W., and EhrenfreundP. (2008) Extraterrestrial nucleobases in the Murchison meteorite. Earth Planet Sci Lett, 270:130–136.
28.
MatereseC.K., NuevoM., BeraP.P., LeeT.J., and SandfordS.A. (2013) Thymine and other prebiotic molecules produced for the ultraviolet photo-irradiation of pyrimidine in simple astrophysical ice analogs. Astrobiology, 13:948–962.
29.
MatereseC.K., NuevoM., and SandfordS.A. (2015) N- and O-heterocycles produced from the irradiation of benzene and naphthalene in H2O/NH3-containing ices. Astrophys J, 800:116–123.
30.
MathisJ.S., MezgerP.G., and PanagiaN. (1983) Interstellar radiation field and dust temperatures in the diffuse interstellar matter and in giant molecular clouds. Astron Astrophys, 128:212–229.
31.
MeierhenrichU.J., Muñoz CaroG.M., SchutteW.A., ThiemannW.H.-P., BarbierB., and BrackA. (2005) Precursors of biological cofactors from ultraviolet irradiation of circumstellar/interstellar ice analogues. Chemistry, 11:4895–4900.
32.
MooreM.H. and HudsonR.L. (1998) Infrared study of ion-irradiated water-ice mixtures with hydrocarbons relevant to comets. Icarus, 135:518–527.
33.
Muñoz CaroG.M., MeierhenrichU.J., SchutteW.A., BarbierB., Arcones SegoviaA., RosenbauerH., ThiemannW.H.-P., BrackA., and GreenbergJ.M. (2002) Amino acids from ultraviolet irradiation of interstellar ice analogues. Nature, 416:403–406.
34.
NishikuraK. (2010) Functions and regulation of RNA editing by ADAR deaminases. Annu Rev Biochem, 79:321–349.
35.
NuevoM., AugerG., BlanotD., and d'HendecourtL. (2008) A detailed study of the amino acids produced from the vacuum UV irradiation of interstellar ice analogs. Orig Life Evol Biosph, 38:37–56.
36.
NuevoM., MilamS.N., SandfordS.A., ElsilaJ.E., and DworkinJ.P. (2009) Formation of uracil from the ultraviolet photo-irradiation of pyrimidine in pure H2O ices. Astrobiology, 9:683–695.
37.
NuevoM., MilamS.N., and SandfordS.A. (2012) Nucleobases and prebiotic molecules in organic residues produced from the ultraviolet photo-irradiation of pyrimidine in NH3 and H2O+NH3 ices. Astrobiology, 12:295–314.
38.
NuevoM., MatereseC.K., and SandfordS.A. (2014) The photochemistry of pyrimidine in realistic astrophysical ices and the production of nucleobases. Astrophys J, 793:125–131.
39.
PrasadS.S. and TarafdarS.P. (1983) UV radiation field inside dense clouds—its possible existence and chemical implications. Astrophys J, 267:603–609.
40.
RiccaA., BauschlicherC.W.Jr, and BakesE.L.O. (2001) A computational study of the mechanisms for the incorporation of a nitrogen atom into polycyclic aromatic hydrocarbons in the Titan haze. Icarus, 154:516–521.
41.
RiosA.C. and TorY. (2013) On the origin of the canonical nucleobases: an assessment of selection pressures across chemical and early biological evolution. Isr J Chem, 53:469–483.
42.
SandfordS.A., BeraP.P., LeeT.J., MatereseC.K., and NuevoM. (2015) Photosynthesis and photo-stability of nucleic acids in prebiotic and extraterrestrial environments. Top Curr Chem, 356:123–164.
43.
ShenC.J., GreenbergJ.M., SchutteW.A., and van DishoeckE.F. (2004) Cosmic ray induced explosive chemical desorption in dense clouds. Astron Astrophys, 415:203–215.
44.
SimonM.N. and SimonM. (1973) Search for interstellar acrylonitrile, pyrimidine, and pyridine. Astrophys J, 184:757–762.
45.
StoksP.G. and SchwartzA.W. (1979) Uracil in carbonaceous meteorites. Nature, 282:709–710.
46.
Van der VeldenW. and SchwartzA.W. (1977) Search for purines and pyrimidines in the Murchison meteorite. Geochim Cosmochim Acta, 41:961–968.
47.
WarnekP. (1962) A microwave-powered hydrogen lamp for vacuum ultraviolet photochemical research. Appl Opt, 1:721–726.
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