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Biomedical subjects

E Cubero

Publications and source records attributed to E Cubero.

5 recordsLinked to original sources
PubMed2001

Theoretical studies of d(A:T)-based parallel-stranded DNA duplexes.

Poly d(A:T) parallel-stranded DNA duplexes based on the Hoogsteen and reverse Watson-Crick hydrogen bond pairing are studied by means of extensive molecular dynamics (MD) simulations and molecular mechanics coupled to Poisson-Boltzmann (MM-PB/SA) calculations. The structural, flexibility, and reactivity characteristics of Hoogsteen and reverse Watson-Crick parallel duplexes are described from the analysis of the trajectories. Theoretical calculations show that the two parallel duplexes are less stable than the antiparallel Watson-Crick duplex. The difference in stability between antiparallel and parallel duplexes increases steadily as the length of the duplex increases. The reverse Watson-Crick arrangement is slightly more stable than the Hoogsteen duplex, the difference being also increased linearly with the length of the duplex. A subtle balance of intramolecular and solvation terms is responsible for the preference of a given helical structure.

DNA↗
PubMed2001

The effect of amino groups on the stability of DNA duplexes and triplexes based on purines derived from inosine.

The effect of amino groups attached at positions 2 and 8 of the hypoxanthine moiety in the structure, reactivity and stability of DNA duplexes and triplexes is studied by means of quantum mechanical calculations, as well as extended molecular dynamics (MD) and thermodynamic integration (MD/TI) simulations. Theoretical estimates of the change in stability related to 2'-deoxyguanosine (G) --> 2'-deoxyinosine (I) --> 8-amino-2'-deoxyinosine (8AI) mutations have been experimentally verified, after synthesis of the corresponding compounds. An amino group placed at position 2 stabilizes the duplex, as expected, and surprisingly also the triplex. The presence of an amino group at position 8 of the hypoxanthine moiety stabilizes the triplex but, surprisingly, destabilizes the duplex. The subtle electronic redistribution occurring upon the introduction of an amino group on the purine seems to be responsible for this surprising behavior. Interesting 'universal base' properties are found for 8AI.

Base Sequence↗
PubMed1998

Is polarization important in cation-pi interactions?

The importance of cation->aromatic polarization effects on cation-pi interactions has been explored. Theoretical calculations demonstrate that polarization is a large contribution to cation-aromatic interactions, and particularly to cation-pi interactions. For a series of compounds with a similar aromatic core, polarization is constant and makes small influence in the relative cation-binding energies. However, when the aromatic core changes polarization contributions might be very different. We found that the generalized molecular interaction potential with polarization is a very fast and powerful tool for the prediction of cation binding of aromatic compounds.

Journal Article↗
PubMed1991

Antiviral effects of xanthate D609 on the human respiratory syncytial virus growth cycle.

The antiviral compound tricyclo-decan-9-yl-xanthogenate (D609) inhibits respiratory syncytial (RS) virus growth in human epithelial (Hep 2) cells. D609 treatment resulted in a decrease in the accumulation of viral proteins, in the phosphorylation of the viral phosphoprotein, and in the amount of extracellular antigens and infectious particles. The relative accumulation of viral proteins was also unbalanced, however no differences were found in the amount of viral RNA with plus or minus polarity. In addition nucleocapsids formation was not inhibited. These observations suggested that this antiviral compound affects the relative proportion of viral proteins and the phosphorylation of P protein. Both features appear to be important in RS virus morphogenesis.

Antigens, Viral↗