Non-natural oligonucleotides represent important (bio)chemical tools and potential therapeutic agents. Backbone modifications altering hybridization properties and biostability can provide useful analogues. Here, we employ an artificial nucleosyl amino acid (NAA) motif for the synthesis of oligonucleotides containing a backbone decorated with primary amines. An oligo-T sequence of this cationic...

one of the great intellectual achievements of 20th century biological science: deciphering of the DNA code by Jim Watson and Francis Crick (Watson & Crick, 1953). It is also the month and year in which The National Human Genome Research Institute announced completing the human genome (Collins et al, 2003). Is this the time to hold a memorial mass to bury social psychiatry, an outmoded corpus of...

In an experiment later named for them, Matthew Stanley Meselson and Franklin William Stahl in the US demonstrated during the 1950s the semi-conservative replication of DNA, such that each daughter DNA molecule contains one new daughter subunit and one subunit conserved from the parental DNA molecule. The researchers conducted the experiment at California Institute of Technology [5] (Caltech) in...

one of the great intellectual achievements of 20th century biological science: deciphering of the DNA code by Jim Watson and Francis Crick (Watson & Crick, 1953). It is also the month and year in which The National Human Genome Research Institute announced completing the human genome (Collins et al, 2003). Is this the time to hold a memorial mass to bury social psychiatry, an outmoded corpus of...

The structure of a DNA aptamer, which was selected for specific binding to arginine, was determined using NMR spectroscopy. The sequence forms a hairpin loop, with residues important for binding occurring in the loop region. Binding of argininamide induces formation of one Watson-Crick and two non-Watson-Crick base pairs, which facilitate generation of a binding pocket. The specificity for argi...

The rigidity and stability of the tertiary structure of yeast tRNAPhe is related to a bond index obtained in an IEHT (iterative extended Hückel theory) calculation. The index permits a quantitative estimate of the electron density along the hydrogen bond, having thus an appealing physical meaning. The results indicate that Hoogsteen-type bonds have, as expected, greater electronic population th...

All pairwise interactions occurring between bases which could be detected in three-dimensional structures of crystallized RNA molecules are annotated on new planar diagrams. The diagrams attempt to map the underlying complex networks of base-base interactions and, especially, they aim at conveying key relationships between helical domains: co-axial stacking, bending and all Watson-Crick as well...

When representing DNA molecules as words, it is necessary to take into account the fact that a word u encodes basically the same information as its Watson–Crick complement θ(u), where θ denotes the Watson–Crick complementarity function. Thus, an expression which involves only a word u and its complement can be still considered as a repeating sequence. In this context, we define and investigate ...

Hydroxyl radicals are potent mutagens that attack DNA to form various base and ribose derivatives. One of the major damaged thymine derivatives is 5-formyluracil (fU), which induces pyrimidine transition during replication. In order to establish the structural basis for such mutagenesis, the crystal structures of two kinds of DNA d(CGCGRATfUCGCG) with R = A/G have been determined by X-ray cryst...

We study the secondary structure of RNA determined by Watson-Crick pairing without pseudo-knots using Milnor invariants of links. We focus on the first non-trivial invariant, which we call the Heisenberg invariant. The Heisenberg invariant, which is an integer, can be interpreted in terms of the Heisenberg group as well as in terms of lattice paths. We show that the Heisenberg invariant gives a...