In this paper we have designed a biosensor device built from B-N substituted graphene nanoribbon within density functional based tight-binding (DFTB) framework. We have investigated the interaction of the nucleobases adenine (A), Guanine (G), Cytosine (C) and Thymine (T) with device. Our calculation suggests that all the nucleobases have different interaction strength when they interact with de...

The structures of all stable tautomers of guanine⋅cytosine and adenine⋅thymine Watson–Crick base pairs produced by single and double proton transfers from the most stable structures are optimized using density functional theory (DFT) at the B3LYP/6-31G(d,p) level. The zwitterionic tautomer of guanine⋅cyosine is stable in a high-dielectric medium (water), but not in the gas phase. Normal mode ca...

1-ethynylpyrene shows remarkable absorption changes upon DNA hybridization when it is covalently attached to the 8-position of guanine. An absorption band at approximately 420 nm is only present in the duplex, exhibits thermal melting behaviour and provides the basis for a molecular beacon together with 1-ethynylpyrene-modified cytosine.

Intense electric fields activate the mutagenic mechanism of a single guanine-cytosine base pair. Would they be able to induce a permanent mutation in real DNA? This question is addressed here by modeling a DNA-embedded fragment with state-of-the-art theoretical tools. We show how DNA can, in principle, be mutated if an appropriate electric field is applied.

Although it is well documented that the immunological activity of cytosine-guanine (CpG) motifs is abrogated by 5' methylation of the cytosine residue, encapsulation within stabilized lipid nanoparticles endows these methylated cytosine-guanine- (mCpG-) containing oligonucleotides (ODNs) with potent immunostimulatory activity in murine animal models. Surprisingly, not only do liposomal nanopart...

Rat liver nuclei were separated into two fractions, the nucleolus and the nucleoplasm, by a combined salt-enzymic extraction. RNA was purified from both sources and analysed on sucrose density gradients. In both fractions a prominent heterogeneous RNA class with mean sedimentation coefficient of 18S was found. This material was analysed by measuring the rate of reaction with formaldehyde, the u...

Tan et al. (Reports, 25 September 2009, p. 1686) argued that loss of tyrosine residues from proteins in metazoans was driven by positive selection to remove potentially deleterious phosphorylation sites. We challenge this hypothesis, providing evidence that the high guanine-cytosine (GC) content of metazoan genomes was the primary driver in the loss of tyrosine residues.

Hybridization-sensitive fluorescent probes have an inherent disadvantage: self-dimerization of the probe prevents the fluorescence quenching prior to hybridization with the target, resulting in a high background signal. To avoid self-dimerization of probes, we focused on a base pair formed by 2'-deoxyinosine (I) and N(4)-ethyl-2'-deoxycytidine (E). I and E bases form more stable base pairs with...

Hydrogen-bonded and stacked structures of adenine-thymine and guanine-cytosine nucleotide base pairs, along with their methylated analogues, are examined with the ab inito based general effective fragment potential (EFP2) method. A comparison of coupled cluster with single, double, and perturbative triple (CCSD(T)) energies is presented, along with an EFP2 energy decomposition to illustrate the...

Chloroplast DNA of the duckweed Spirodela oligorrhiza, isolated by CsCl gradient centrifugation, was characterized by its buoyant density, guanine + cytosine content, melting behavior, circularity, and contour length. In all these characteristics, chloroplast DNA of S. oligorrhiza is similar to the chloroplast genomes of other higher plants, except that it has a significantly larger size.