Remarques sur le crotonoside

Cherbuliez, Emile; Bernhard, Karl

doi:10.1002/hlca.193201501106

Cited by 24 publications

(26 citation statements)

References 2 publications

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“…It remained generally accepted until 1927 when Robinson questioned the occurrence of rihosc in the nucleosides and nucleotides (326). He believed that the hydrolysis in the isolation process causes a Walden inversion which would yield ribose from another sugar, but this theory was speedily disproved by Levene (240), and the isolation of this carbohydrate from various nucleosidex under different conditions of hydrolysis corroborated Levene's contention (67,336,374). Only in recent years has the occurrence of pentoses other than Dribose in pmtose nucleic acids been seriously considered again.…”

Section: C; Carbohydratesmentioning

confidence: 59%

“…Isoguanosine (crotonoside) has been discovered by Cherbuliez and Bernhard (67) in croton seeds (Tiglizm croton) . This unusual material has attracted the interest of biochemists for several reasons: Besides croton oil it contains the extremely toxic protein crotin (104) and shows highly allergenic properties; hence, the preparation of crotonoside from the seeds requires precautions which are unusual in nucleotide chemistry (373a).…”

Section: Nucleosidesmentioning

confidence: 99%

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Chemistry and Enzymology of Nucleic Acids

Schlenk

1949

Advances in Enzymology - And Related Areas of Molecular Biology

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Section: C; Carbohydratesmentioning

confidence: 59%

Section: Nucleosidesmentioning

confidence: 99%

Chemistry and Enzymology of Nucleic Acids

Schlenk

1949

Advances in Enzymology - And Related Areas of Molecular Biology

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“…5'-isoGMP was obtained directly by the photochemical rearrangement of the N I -oxide of 5'-AMP, as elsewhere described [13], and converted by the morpholidate procedure [14] to the sodium salt of Poly(G), poly (1) and poly(X) were obtained from Miles, and poly(A), poly(C) and poly(U) from Calbiochem (New York, U.S.A.). Pancreatic RNase was a product of Reanal (Budapest, Hungary), while RNase T, originated from Sankyo (Tokyo, Japan) and snake venom phosphodiesterase from Sigma (St Louis, Mo., U.S.A.).…”

Section: Methodsmentioning

confidence: 99%

Preparation and Properties of an Analogue of Poly(A) and Poly(G): Poly(isoguanylic acid)

et al. 1976

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Isoguanosine-5'-pyrophosphate, in the presence of an oligonucleotide primer, was polymerized by Eschrrichiu coli polynucleotide phosphorylase under conditions analogous to those required for polymerization of 5'-GMP. The resulting poly(isoguany1ic acid), poly(isoG), was a multistranded helix with a stability considerably higher than that of poly(G), and fully resistant to various nucleolytic enzymes. The polymer exhibited a two-step temperature transition profile in moderately alkaline propylene glycol. Alkaline titration in aqueous medium, by ultraviolet and circular dichroism spectroscopy, showed two clearly defined transitions, the second of which was fully cooperative. The accompanying changes in sedimentation constants were consistent with a structure for poly(isoG) of a fourstranded helix, like neutral poly(G). In acid medium, spectral and potentiometric titrations demonstrated the existence of more than one transition in the pH range 6-1.2, with accompanying protonation of the isoguanosine residues. In neutral medium the polymer formed no complexes with other potentially complementary homopolymers. In acid medium, on the other hand, the protonated form of poly(isoG) did form a triple-stranded complex with poly(I), viz. 2poly(I) . poly(isoG)+.Possible structures are formulated for the neutral and protonated forms of poly(isoG) which account for the two-step thermal transition in alkaline propylene glycol and on alkaline titration in aqueous medium. The nature of the protonated form, and its complex with poly(1) is also discussed.Crotonoside, a purine derivative originally isolated from croton beans and shown to yield isoguanine and D-ribose on acid hydrolysis [l], was subsequently found to be identical with 9-f3-~-ribofuranosylguanine (isoguanosine, isoG), synthesized by Davoll [2] by deamination of 2,6-diamino-9-fl-~-

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“…1b). iG itself occurs naturally (7) and may be considered an elementary nucleobase in the sense that it derives from hydrogen cyanide, a prime prebiotic reagent (8). Thus, iG may have contributed to early biopolymer evolution (9) and has been used to encode genetic information during ribosomal translation in vitro (10).…”

mentioning

confidence: 99%

A DNA pentaplex incorporating nucleobase quintets

Chaput

Switzer

1999

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

124

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Supramolecular self-assembly is an integral step in the formation of many biological structures. Here we report a DNA pentaplex that derives from a metal-assisted, hydrogen bond-mediated self-assembly process. In particular, cesium ions are found to induce pentameric assembly of DNA bearing the nonstandard nucleobase iso-guanine. The pentaplex was designed by using a simple algorithm to predict nucleobase structural requirements within a quintet motif. The design principles are general and should extend to complexes beyond pentaplex. Structures exhibiting molecularities of five or more were previously accessible to peptides, but not nucleic acids.In abiologic systems, metal-mediated self-assembly has yielded arrays (1), nanometer-sized dendrimers (2), and other systems (3), notably, double-and triple-helical metal complexes that bear a formal resemblance to DNA (4). Recognition in the latter is driven by ligand constraints and metal coordination geometry. Recognition within DNA double and triple helices, in contrast, depends primarily on hydrogen bond complementarity. Quadruple helices of DNA based on the G-quartet motif are unusual, however, in that they rely on both hydrogen bonding and metal ion coordination (5, 6). Here we demonstrate the ability to expand DNA molecularity beyond quadruplexes by engineering nucleobases to fit dimensions required of higher-order motifs. Specifically, we design and characterize a DNA pentaplex.The iG-motif (iG refers to 2Ј-deoxy-iso-guanosine) may be predicted to yield the first nonquartet structure within the series shown in Fig. 1, which also illustrates working design principles to expand nucleobase motifs. Each of the generalized motifs in this figure is modular and comprised of components for which an ideal sector angle may be attributed, e.g., 360͞4°and 360͞5°for quartets and quintets, respectively. In the case of G-quartets, vectors along hydrogen bond donor͞ acceptor groups contributing to recognition result in the 90°i deal sector angle (Fig. 1a). In contrast to G, the 67°sector angle of iG approaches the quintet optimum (Fig. 1b). iG itself occurs naturally (7) and may be considered an elementary nucleobase in the sense that it derives from hydrogen cyanide, a prime prebiotic reagent (8). Thus, iG may have contributed to early biopolymer evolution (9) and has been used to encode genetic information during ribosomal translation in vitro (10). We (11) and others (12, 13) have established that higher-order self-pairing of iG depends on metal ions, similar to G-quartets (for iG self-pairing in another sugar system, see ref. 32). Our present findings show that monovalent cations can influence decisively the degree of strand association in a nonstandard DNA. Whereas tetraplexes are observed as the major outcome of incubating iG-rich DNA in the presence of potassium ions, pentaplex association dominates under the influence of cesium ions. As a consequence, the iG-motif fulfills geometric predictions.

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Remarques sur le crotonoside

Cited by 24 publications

References 2 publications

Chemistry and Enzymology of Nucleic Acids

Chemistry and Enzymology of Nucleic Acids

Preparation and Properties of an Analogue of Poly(A) and Poly(G): Poly(isoguanylic acid)

A DNA pentaplex incorporating nucleobase quintets

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