The structures of polyinosinic acid

Thiele, Danielle; Guschlbauer, Wilhelm

doi:10.1007/bf01184691

Cited by 77 publications

(30 citation statements)

References 26 publications

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“…The pure uv and CD spectra obtained for the four detected species, and their distribution plot (concentration profiles) with pH, are given in Figures 2-4. From previous studies, 11,26 it is known that the CD spectra of protonated and deprotonated poly(I) have a very low intensity at any pH value in relation to the CD spectra of all the species of poly(C). Therefore, the CD spectra obtained for the different The comparative study between the pure CD spectra poly(I0) and poly(C).…”

Section: Poly(i)-poly(c)-h Systemmentioning

confidence: 92%

Acid-base and copper (II) complexation equilibria of poly(inosinic)-poly(cytidylic)

1997

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The acid‐base and copper (II) complexing properties of the heteropolynucleotide poly(inosinic)‐poly(cytidylic) acid were studied by means of potentiometric, spectrophotometric, CD, and molecular fluorescence titrations in a working aqueous medium of 0.15 M ionic strength at 37°C. The study of the acid‐base equilibria has proved the existence of four different species in the pH interval 2–11. Two new species are detected in the presence of copper(II) ion, at acidic and neutral pH values. Spectrophotometric, CD, melting, and fluorescence data were treated with a multivariate curve resolution procedure that allowed the determination of the number of species simultaneously present in each system [acid‐base equilibria, copper(II) complexation equilibria], and the estimation of their concentration profiles and of the pure spectra for each species. From the concentration profiles an unambiguous assignment of which species are present at any pH conditions can be made. Furthermore, the knowledge of the pure uv‐visible, fluorescence, and CD spectra recovered by the proposed resolution method for each species brings important structural information. When this mathematical approach was applied to the thermal denaturation data, the melting profile and the uv pure spectra for all the different species or conformations formed in the melting process, were calculated. © 1997 John Wiley & Sons, Inc. Biopoly 42: 271–283, 1997

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Section: Poly(i)-poly(c)-h Systemmentioning

confidence: 92%

Acid-base and copper (II) complexation equilibria of poly(inosinic)-poly(cytidylic)

1997

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“…4 The study of polyinosinic acid (poly rI) can be traced back to as early as the 1950s and has been extensively investigated by a variety of physical techniques, including fiber diffraction and solution spectroscopy. 5 In 1958, Rich proposed a model of a three parallel stranded structure with base-triplets as the repeating unit based on the fiber diffraction data of poly rI. 6 However, two later independent studies indicated that poly rI adopts the quadruplex conformation.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure of an RNA Quadruplex Containing Inosine Tetrad: Implications for the Roles of NH2 Group in Purine Tetrads

Pan

Shi

Sundaralingam

2006

Journal of Molecular Biology

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“…D'ailleurs, le minimum de la bande d'absorption du poly(1) a 95°C se situe toujours a 249 nm en presence de (dien)Pd(II), comparativement a 247 nm pour le poly(1) libre, ce qui montre que le Pd(I1) est complex6 au poly(1) dans ces conditions. La diminution graduelle de la temperature conduit a une renaturation trks lente du polymkre, caractiristique du poly(1) (19). La vitesse de renaturation semble augmenter cependant avec la concentration en (dien)Pd(II).…”

Section: Partie Experimentaleunclassified

“…Un tel accroissement de I'intensitt peut &tre attribue a la formation d'une structure helicoi'dale ordonnee. La forme de ce spectre est differente cependant de celles generalement attribuees la multiple helice du poly (1) a force ionique elevee ou i basse temperature (19,20). En particulier, la bande negative vers 280 nm pour le poly(1) libre est remplacee par une bande positive en presence du (dien)Pd(II).…”

Section: Partie Experimentaleunclassified

Étude cinétique et thermodynamique de l'interaction d'un complexe de Pd(II) avec l'inosine et l'acide polyinosinique

Ménard¹,

Zador²

1988

Can. J. Chem.

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R e p le 26 mai 1987ROBERT M~N A R D et MIKLOS ZADOR. Can. J. Chem. 66, 178 (1988). Les rCactions du complexe (dien)Pd(II) avec I'inosine et I'acide polyinosinique ont Ct C CtudiCes a I'aide de mtthodes spectroscopiques et de flux-stoppC. Dans les deux cas, le metal se lie initialement au site N7 de la base hypoxanthine. Les rCsultats des etudes cinCtiques indiquent que le mecanisme implique deux voies rCactionnelles : une substitution nuclkophile directe ainsi qu'une reaction via un intermediaire aquo. Les rCactions sont plus rapides dans le cas du poly(I), due a la forte densit6 de charges nCgatives de ce polymkre. La rCaction initiale au site N7 est suivie d'une redistribution lente du metal vers le site NI thermodynamiquement plus stable. La fixation du (dien)Pd(II) au poly(1) induit la formation d'une structure multi-hClicoi'dale stable du polymkre. Cette structure a Ct C caractCrisCe par des mesures d'absorbance et de dichroi'sme circulaire ainsi que par la dktermination de la courbe de fusion du polymkre. I1 a aussi Ct C observC qu'en prCsence du complexe de Pd(II), le poly(1) peut Ctre hydrolysC B pH alcalin, dans des conditions relativement douces.ROBERT M~N A R D and MIKLOS ZADOR. Can. J. Chem. 66, 178 (1988) Reactions of the (dien)Pd(II) complex with inosine and polyinosinic acid were studied by spectroscopic and stopped-flow methods. In both cases, the metal initially binds at the N7 site of the hypoxanthine base. The results of kinetic studies indicate the existence of a two-path mechanism: a direct nucleophilic substitution and a solvent path with formation of an aquo intermediate. The reactions are faster for poly(I), due to the high density of negative charges for this polymer. The initial reaction at N7 is followed by a slow redistribution of the metal towards the thermodynamically more stable N I site. Binding of (dien)Pd(II) to poly(1) leads to formation of a stable, multistranded helicoidal structure of the polymer. This structure was characterized by absorption and circular dichroism measurements and by the melting curve of the polymer. It was also observed that in presence of the Pd(I1) complex, poly(1) can be hydrolyzed at relatively mild conditions at high pH.

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The structures of polyinosinic acid

Cited by 77 publications

References 26 publications

Acid-base and copper (II) complexation equilibria of poly(inosinic)-poly(cytidylic)

Acid-base and copper (II) complexation equilibria of poly(inosinic)-poly(cytidylic)

Crystal Structure of an RNA Quadruplex Containing Inosine Tetrad: Implications for the Roles of NH2 Group in Purine Tetrads

Étude cinétique et thermodynamique de l'interaction d'un complexe de Pd(II) avec l'inosine et l'acide polyinosinique

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