Base dynamics, heretofore observed only at TpA steps in DNA, were investigated as a function of sequence context by NMR spectroscopy. The large amplitude conformational dynamics have been previously observed in TnAn segments where n > or = 2. In order to determine whether the dynamic characteristics occur in more general sequence contexts, we examined four self-complementary DNA sequences, [d(C...

The denaturation of the double helix is a template for fundamental biological functions such as replication and transcription involving the formation of local fluctuational openings. The denaturation transition is studied for heterogeneous short sequences of DNA, i.e. ~100 base pairs, in the framework of a mesoscopic Hamiltonian model which accounts for the helicoidal geometry of the molecule. ...

Semi-classical simulations of the UV-photoabsorption cross sections of adenine, guanine, cytosine, thymine, and uracil in gas phase were performed at the resolution-of-identity coupled cluster to the second-order (RI-CC2) level. With the exception of cytosine, the spectra of the other four nucleobases show a two band pattern separated by a low intensity region. The spectrum of cytosine is shape...

Using a nonempirically tuned range-separated DFT approach, we study both the quasiparticle properties (HOMO-LUMO fundamental gaps) and excitation energies of DNA and RNA nucleobases (adenine, thymine, cytosine, guanine, and uracil). Our calculations demonstrate that a physically motivated, first-principles tuned DFT approach accurately reproduces results from both experimental benchmarks and mo...

The conformation of DNA's with adenine-thymine tracts exhibiting retardation in electrophoretic migration and considered as curved were investigated in solution by CD and RAMAN spectroscopy. The following curved multimers with adenine tracts but of different flanking sequences d(CA5TGCC)n, d(TCTCTA6TATATA5)n, d(GA4T4C)n yield CD spectroscopic features indicating a non-B structure of the dA.dT t...

Electronic coupling V(da) is one of the key parameters that determine the rate of charge transfer through DNA. While there have been several computational studies of V(da) for hole transfer, estimates of electronic couplings for excess electron transfer (ET) in DNA remain unavailable. In the paper, an efficient strategy is established for calculating the ET matrix elements between base pairs in...

A considerable amount of evidence indicates that desoxyribonucleie acid is capable of duplicating itself, a property also possessed by genes. (By a selfduplicating material, we mean one which plays some essential role in its own production.) Watson & Crick (1) have proposed a new structure for desoxyribonucleic acid which not only takes into account the existing analytical and x-ray diffraction...