Search results for "Polynucleotide"
showing 7 items of 37 documents
Self-instructed condensation of amino acids and the origin of biological information
1984
In contemporary cells biological information is largely stored in nucleic acids. Therefore, a prerequisite in many theories on the origin of cellular life is the pre-existence of self-replicating polynucleotides that had to be formed by abiotic processes on the prebiotic Earth. It is usually assumed that the spontaneous synthesis of a self-replicating polynucleotide could take place readily. However, serious stereochemical obstacles exist which make such a synthesis extremely improbable. Amino acids, on the other hand, which are abundantly formed in prebiotic simulation experiments, are relatively easily polymerized to macromolecules (protoproteins) that share with modern proteins many prop…
Spectroscopic study of polynucleotides in cationic W/O microemulsions
2007
Water has an active and key role in determining the structure of DNA. Entrapment of DNA and of synthetic model polynucleotides in reverse micelles, where the water activity can easily be modulated, may be a useful way of assessing the influence of water on DNA characteristics; it may also offer useful ideas on the problem of how the giant DNA molecule can be confined in the limited space of cell nuclei. The quaternary microemulsion CTAB n-hexane|n-pentanol| water was used to entrap calf thymus DNA, and the model polynucleotides single-strand polyA, single-strand polyT and duplex polyAT. Ultraviolet spectros-copy, specifically the band at 260 nm, was used to compare the pairing of complement…
Revealing interactions between polyaza pyridinophane compounds and DNA/RNA polynucleotides by SERS spectroscopy
2014
Surface-enhanced Raman scattering spectroscopy (SERS) in the near-infrared region had been applied to study interactions of polyaza pyridinophanes with single stranded RNA and double stranded DNA and RNA polynucleotides. Studied compounds, PYPOD and PHENPOD, differed in the central aromatic moiety, pyridine and phenanthroline, respectively, which linked two cyclic amines. An intense scattering was obtained from molecules adsorbed onto the silver nanoparticles, showing nonlinear concentration dependence in the 6.5 × 10−8−6.5 × 10−5 M range. New bands in spectra of PYPOD/polynucleotide and PHENPOD/polynucleotide mixtures were assigned to vibrational modes of polynucleotide moieties involved i…
The CdCl2 effects on synthetic DNAs encaged in the nanodomains of a cationic water-in-oil microemulsion
2011
The present work is dedicated to the study of the interactions of CdCl(2) with the synthetic polynucleotides polyAT and polyGC confined in the nanoscopic aqueous compartment of the water-in-oil microemulsion CTAB/pentanol/hexane/water, with the goal to mimic in vitro the situation met by the nucleic acids in vivo. In biological structures, in fact, very long strings of nucleic acids are segregated into very small compartments having a radius exceedingly smaller than the length of the encapsulated macromolecule. For comparison, the behaviour of polyGC was also studied in aqueous solutions of matched composition. The conformational and thermal stabilities of both polynucleotides enclosed in t…
Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays.
2017
Three polyaminocyclodextrin materials, obtained by direct reaction between heptakis(6-deoxy-6-iodo)-β-cyclodextrin and the proper linear polyamines, were investigated for their binding properties, in order to assess their potential applications in biological systems, such as vectors for simultaneous drug and gene cellular uptake or alternatively for the protection of macromolecules. In particular, we exploited polarimetry to test their interaction with some model p-nitroaniline derivatives, chosen as probe guests. The data obtained indicate that binding inside the host cavity is mainly affected by interplay between Coulomb interactions and conformational restraints. Moreover, simultaneous i…
Guanosine 5'-diphosphate 3'-diphosphate (ppGpp) as a negative modulator of polynucleotide phosphorylase activity in a 'rare' actinomycete.
2010
Abstract With the beginning of the idiophase the highly phosphorylated guanylic nucleotides guanosine 5'-diphosphate 3'-diphosphate (ppGpp) and guanosine 5'-triphosphate 3'-diphosphate (pppGpp), collectively referred to as (p)ppGpp, activate stress survival adaptation programmes and trigger secondary metabolism in actinomycetes. The major target of (p)ppGpp is the RNA polymerase, where it binds altering the enzyme activity. In this study analysis of the polynucleotide phosphorylase (PNPase)-encoding gene pnp mRNA, in Nonomuraea sp. ATCC 39727 wild-type, constitutively stringent and relaxed strains, led us to hypothesize that in actinomycetes (p)ppGpp may modulate gene expression at the leve…
Cationic microemulsion hosting polynucleotides: Effect of NaCl on host and guest
2004
The structural features of the quaternary water-in-oil microemulsion CTAB/n-hexane/n-pentanol/water in the presence of fairly high concentrations of NaCl and of relatively high molecular weight polynucleotides have been determined. Even in these severe conditions, the hosting system can still be depicted as formed by water droplets stabilised by a surfactant/cosurfactant layer. Moreover, the time stability of the host/guest system has been evaluated and the phase behaviour of the hosting system in the presence of increasing concentrations of NaCl determined.