The 1-propynylation at C5 of consecutive pyrimidines in DNA can enhance DNA:RNA hybrid stability at 37 degrees C by over 1 kcal/mol of substitution [Barnes, T. W., III; Turner, D. H. J. Am. Chem. Soc.2001, 123, 4107-4118]. To provide information on the structural consequences of propynylation, two-dimensional NMR spectroscopy was used to study the structures of several oligonucleotides. Intrare...

This work was supported by the Royal Society of New Zealand through a Marsden grant. We acknowledge the use of extensive computer time on Massey University’s parallel supercomputer facilities Doublehelix and Bestgrid. Dr. Matthias Lein, Prof. Dr. Peter Schwerdtfeger, Center for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, Private B...

Following photodissociation of 2-chloropropene (H(2)CCClCH(3)) at 193 nm, vibration-rotationally resolved emission spectra of HCl (upsilon < or = 6) in the spectral region of 1900-2900 cm(-1) were recorded with a step-scan time-resolved Fourier-transform spectrometer. All vibrational levels show a small low-J component corresponding to approximately 400 K and a major high-J component correspond...

Experiments designed to simulate the low temperature surface chemistry occurring in interstellar clouds provide clear evidence of a reaction between oxygen atoms and propyne ice. The reactants are dosed onto a surface held at a fixed temperature between 14 and 100 K. After the dosing period, temperature programmed desorption (TPD), coupled with time-of-flight mass spectrometry, are used to iden...

One of the problems that hamper the use of antisense DNAs as effective drugs is the non-specific binding of chemically-modified oligonucleotides to cellular proteins. We previously showed that the affinity of a model ssDNA-binding protein, the Ff gene 5 protein (g5p), was >300-fold higher for phosphorothioate-modified DNA (S-DNA) than for unmodified dA(36), consistent with the propensity of S-D...

The reaction dynamics of the dicarbon molecule with D3-methylacetylene, CD3CCH(X A1), were investigated utilizing the crossed molecular beams approach. By combining the experimental results on the atomic hydrogen versus deuterium loss channels with electronic structure calculations, we could substantiate that the D3CCCCC(X A) radical is neither formed on the singlet nor on the triplet surface. ...

Acetylene is a slow-binding inhibitor of the Ni- and Fe-containing dimeric hydrogenase isolated from Azotobacter vinelandii. Acetylene was released from hydrogenase during the recovery from inhibition. This indicates that no transformation of acetylene to another compound occurred as a result of the interaction with hydrogenase. However, the release of C2H2 proceeds more rapidly than the recove...

Motivated by the recent detection of propene (C3H6) in the atmosphere of Titan, we use a one-dimensional Titan photochemical model with an updated eddy diffusion profile to systematically study the vertical profiles of the stable species in the C3-hydrocarbon family. We find that the stratospheric volume mixing ratio of propene (C3H6) peaks at 150 km with a value of 5 × 10, which is in good agr...