Multinuclear NMR investigation of the NaDNA/ethidium bromide anisotropic system

A combined use of P-31, Na-23, H-2 and O-17 NMR spectroscopies and polarized light microscopy has been employed to investigate the effect of the ethidium bromide (EB) binding on the liquid crystalline phase of concentrated double stranded DNA solutions. The optical textures and the P-31 and Na-23 NMR spectra of the DNA anisotropic solutions show that the intercalation of EB induces significant modifications either in the arrangements of the DNA rods and the surrounding ionic atmosphere. On the contrary, no indication of significant changes of the orientational order of the water molecules around DNA emerges from the water H-2 and O-17 NMR spectra

Adaptative value of a PKC-PKI55 feedback loop of inhibition that prevents the kinase's deregulation.

A 168-bp amplification product was obtained in RT-PCR experiments using a degenerate oligonucleotide designed on a five-amino acid sequence of IN, a 7-kDa protein, previously characterized as a PKC inhibitor. It was included in the coding ORF of the 1530-bp-long IMAGE clone ID 38900 (accession numbers R51337 and R51448) that produces a translation product of 6.5 kDa. The translation of the ORF conceptual reading frame allowed the preparation of the synthetic protein PKI55, which was found to inhibit and degrade both untreated nPKC d isozymes and activated cPKC isozymes. The PKI55 gene is localized in chromosome 2q35. The Repeat Maskers output showed a 533-bp-long LTR32/ERVL segment that included the PKI55 coding sequence and a complete regulatory region. The coding sequence and the structure of PKI55 were detected in a brain cDNA of Macaca fascicularis (diverged from human lineages about 25 Myr ago). Three other human genes with over 60% identities with PKI55 were identified in three different loci (i.e., chromosomes 10, 15, and 20.) Synthesis of PKI55 was stimulated by PKC activation. A feedback loop of inhibition is established. When the PKCs are overactivated, PKI55 induces degradation of the enzyme and prevents the isozyme overexpression implicated in a number of important diseases including cancer, diabetes, and disorders of the immune system. The presence of the PKI55 sequence in Macaca fascicularis as well as in human chromosomes 10, 15, and 20 indicates a selective advantage for the PKI55 sequence and the adaptive value of the feedback mechanism

A 23Na NMR study of the effect of D(+) and L(-) arabitol on NaDNA in aqueous solution.

The 23Na NMR quadrupolar relaxation in NaDNA aqueous solutions has been investigated in the presence of D(+) and L(-) arabitol. Quite different results were produced by the enantiomers, i.e. the addition of D(+) arabitol produced a small increase of the 23Na NMR relaxation rates, while in the presence of L(-) arabitol a significant decrease was observed. These findings were analysed and discussed in terms of an effective interaction of L(-) arabitol with DNA

Discovery of a structural-element specific g-quadruplex "light-up" probe

10.1038/srep03776Scientific Reports4