2-Aminoadenine is an adenine substituting for a base in S-2L cyanophage DNA

Kirnos, M. D.; Khudyakov, Ivan; Alexandrushkina, N. I.; Vanyushin, B. F.

doi:10.1038/270369a0

Cited by 146 publications

(93 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Following the interpretation of the CD spectrum of p0ly(2NH~A).poly(U),~ which has a negative band a t 286 nm and an A-conformation, Kirnos et al 4.j attribute the long-wavelength band to the B~u transition of BNHzA, while noting the difference of sign. We find that the CD spectrum of poly(2NH2dA)-poly(dT) does indeed have a positive long-wavelength band a t 297 nm ( Fig.…”

mentioning

confidence: 99%

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH₂A

Howard¹,

Miles²

1983

Biopolymers

View full text Add to dashboard Cite

2-Aminopolyadenylic acid and its helical complexes have been thoroughly examined in the ribopolynucleotide series,1-3 but comparable information is not available in the deoxy series. The need for such information has been highlighted recently by the remarkable discovery of a new kind of DNA by Kirnos et a1.495 They have found that the DNA of cyanophage S-2L has all of its A residues replaced by 2NH2A. They have reported its thermal stability and anomalous CD spectrum and, in the absence of deoxy models, have based their interpretation on ribopolynucleotide studies2 Further biological interest in 2-aminopolydeoxyadenylic stems from the work of Stahl and Chamberlin,G who found that in T7 DNA promoter regions, 2NH2A is read as G rather than as A. The enzyme evidently recognizes the NH2 in the minor groove without reference to base pairing. Within a transcribed region, however, 2NHzA is read and transcribed as A by a base-pairing mechanism. To obtain basic chemical information relevant to biological properties of 2NH2A, we have synthesized 2-aminopolydeoxyadenylic acid and characterized its interaction with other polynucleotides. 2NH2dAMP was synthesized by the Tener p r~c e d u r e ,~ modified by addition of triethylamine to prevent the rapid depurination that occurs in the unmodified procedure. The triphosphate was made by the method of Moffatt and Khorana.s We polymerized the substrate with deoxynucleotidyl transferaseg following the procedure of Willis.l0 Synthesis of the same nucleotide and polymer has recently been reported.l1 A more detailed report of the synthetic method and physical properties will be published separately.The CD spectrum of S-2L DNA is anomalous in having two positive long-wavelength bands, a t 290 and 265 nm, rather than the usual single positive band a t -275 nm. Following the interpretation of the CD spectrum of p0ly(2NH~A).poly(U),~ which has a negative band a t 286 nm and an A-conformation, Kirnos et al.4.j attribute the long-wavelength band to the B~u transition of BNHzA, while noting the difference of sign. We find that the CD spectrum of poly(2NH2dA)-poly(dT) does indeed have a positive long-wavelength band a t 297 nm (Fig. l), identical in sign and similar in wavelength to the long-wavelength band of S-2L DNA. Reasons for assigning transitions in CD spectra of polymers containing 2NH2A residues have been presented previously in some detail.2 We follow that reasoning in the present case and assign the positive band a t 297 nm to exciton splitting of the BPU transition of 2NH2A a t -278 nm. The expected negative lobe of the splitting may contribute, presumably overlapped by a T transition, to the minimum observed at 270 nm. The

show abstract

mentioning

confidence: 99%

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH₂A

Howard¹,

Miles²

1983

Biopolymers

View full text Add to dashboard Cite

show abstract

“…68. 2,6-Diamino purine (9), considered as possible extraterrestrial marker because it is not typically found in terrestrial biochemistry (62), operates in some microorganisms as bioisoster of adenine efficiently pairing with thymine by three intramolecular hydrogen bonds, thus eliminating the major difference between the two types of Watson-Crick interactions (68). Orotic acid (10) is a key intermediate in the pyrimidine synthesis pathway (69), whereas 4,6-dihydroxypyrimidine (11) is one of the possible isomers of uracil.…”

Section: Resultsmentioning

confidence: 99%

Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation

Saladino

Carota

Botta

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

165

157

View full text Add to dashboard Cite

Liquid formamide has been irradiated by high-energy proton beams in the presence of powdered meteorites, and the products of the catalyzed resulting syntheses were analyzed by mass spectrometry. Relative to the controls (no radiation, or no formamide, or no catalyst), an extremely rich, variegate, and prebiotically relevant panel of compounds was observed. The meteorites tested were representative of the four major classes: iron, stony iron, chondrites, and achondrites. The products obtained were amino acids, carboxylic acids, nucleobases, sugars, and, most notably, four nucleosides: cytidine, uridine, adenosine, and thymidine. In accordance with theoretical studies, the detection of HCN oligomers suggests the occurrence of mechanisms based on the generation of radical cyanide species (CN·) for the synthesis of nucleobases. Given that many of the compounds obtained are key components of extant organisms, these observations contribute to outline plausible exogenous high-energy-based prebiotic scenarios and their possible boundary conditions, as discussed.origin of life | formamide | prebiotic syntheses | nucleosides | meteorites H ypothesizing formamide (FA) as parent molecule, we explored its potentiality in synthetic processes when exposed to proton irradiation. The purpose of this analysis is to verify a possible prebiotic scenario consisting of FA, considered here as starting one-carbon atom material, of proton beams mimicking solar energetic particles as energy source, and of meteorites as catalysts. The rationale of this approach is that the results could help in outlining exogenous prebiotic models and their boundaries.FA (NH 2 CHO) is becoming one of the most intensively studied precursors for prebiotic syntheses of compounds potentially relevant for the origin of life (1-4). FA is a ubiquitous molecule in the universe. It has been detected in galactic centers (Sgr A and Sgr B), in star-forming regions of dense molecular clouds, in high-mass young stellar objects, in the interstellar medium and in comets and satellites (5)(6)(7)(8)(9)(10)(11)(12)(13)(14).With the appropriate mineral as catalyst, different ensembles of intermediates of genetic and metabolic apparatuses are simultaneously synthesized from FA under thermal conditions (i.e., by heating liquid FA between 333 and 453 K at room pressure). DNA and RNA components (15-21), amino acids (22, 23), sugars (24), and carboxylic acids (25, 26) have been obtained. Minerals tune the selectivity of these transformations (1, 2), the mechanistic pathways for the synthesis of nucleobases requiring pyrimidine (27-30) or imidazole intermediates (31,32).Within the solar system, ionizing cosmic radiation is generated by the Sun [solar cosmic rays (SCRs), primarily protons accelerated by flares and coronal mass ejections to energies typically of tens to hundreds megaelectronvolts] and is also formed by particles coming from the deep universe [galactic cosmic rays (GCRs)] (33). The SCRs and GCRs differ in their components and energy spectra, but their overwhelming co...

show abstract

“…Diaminopurine nucleoside 1 (34), which can form three hydrogen bonds with dT, stabilizes the dA-dT pair only very little, in contrast to the canonical tridentate dG-dC pair. Oligonucleotides incorporating the pyrazolo [3,4-d]pyrimidin-4,6-diamine nucleoside 2a instead of 1 form more stable duplex structures.…”

Section: Discussionmentioning

confidence: 99%

Pyrazolo[3,4-d]pyrimidine Nucleic Acids: Adjustment of the dA-dT to the dG-dC Base Pair Stability

Budow

Seela

2003

Nucleosides, Nucleotides and Nucleic Acids

View full text Add to dashboard Cite

2-Aminoadenine is an adenine substituting for a base in S-2L cyanophage DNA

Cited by 146 publications

References 18 publications

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH₂A

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH₂A

Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation

Pyrazolo[3,4-d]pyrimidine Nucleic Acids: Adjustment of the dA-dT to the dG-dC Base Pair Stability

Contact Info

Product

Resources

About

2-Aminoadenine is an adenine substituting for a base in S-2L cyanophage DNA

Cited by 146 publications

References 18 publications

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH2A

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH2A

Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation

Pyrazolo[3,4-d]pyrimidine Nucleic Acids: Adjustment of the dA-dT to the dG-dC Base Pair Stability

Contact Info

Product

Resources

About

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH₂A

Poly(2‐aminodeoxyadenylic acid): Circular dichroism and thermal stability of its complexes and their relevance to phage DNA in which A is replaced by 2NH₂A