Nucleic acids structural diversity

The three major classes of biopolymers found in eukaryotic systems are nucleic acids, proteins, and polysaccharides. The latter class is the most complex with respect to structural and stereochemical diversity. Polysaccharides indeed possess a massive information content. Furthermore, polysaccharides are commonly found in nature covalently attached (conjugated) to other biomolecules such as proteins, isoprenoids, fatty acids, and lipids.1... 

Additionally, nucleic acid bases have been used in the dynamic assembly of mixed-metal, mixed-pyrimidine metallacalix[n]arenes [47]. In this approach, Lippert and coworkers investigated the dynamic assembly of metallacalixarenes based on platinum (Pt ), palladium (Pd°), uracil, and cytosine assemblies with mixed amines. These combinations form cyclic metallacalix[n]arenes structures with n = A and = 8. Of the metallacalix[4]arenes, compounds were formed with five, six, and eight bonded metals, and a variety of nucleobase coimecfivities (UCUC and UCCU). The dynamic nature of this assembly allows access to novel and structurally diverse set of nucleobase metallacalixarenes. 

The terminology nucleotide or nucleoside immediately directs our thoughts towards nucleic acids. Remarkably, nucleosides and nucleotides play other roles in biochemical reactions that are no less important than their function as part of nucleic acids. We also encounter more stmctural diversity. It is rare that the chemical and biochemical reactivities of these derivatives relate specihcally to the base plus sugar part of the structure, and usually reside elsewhere in the molecule. Almost certainly, it is this base plus sugar part of the structure that provides a recognition... 

Like most trace elements, nickel can activate various enzymes in vitro, but no enzyme has been shown to require nickel, specifically, to be activated. Howevei, mease has been shown to be a nickel metalloenzyme and has been found to contain 6 to 8 atoms of nickel per mole of enzyme (Fishbein et al.. 1976). RNA (ribonucleic add) preparations from diverse sources consistently contain nickel in concentrations many times higher than those found in native materials from which the RNA ts isolated (Wacker-Vallee, 1959 Sunderman, 1965). Nickel may serve to stabilize the ordered structure of RNA. Nickel may have a role in maintaining ribosomal structure (Tal, 1968, 1969). These studies and other information have led to the suggestion that nickel may play a role in nucleic acid and/or protein metabolism. 

TODD, SIR ALEXANDER R. (1907-1997). A British chemist who won the Nobel prize for chemistry in 19.57. His diverse research and accomplishments involved phosphorylation and mechanisms of biological reactions concerning phosphates. Many of his studies concerned the structure of nucleic acids, nucleotides, nucleotidic coenzynies, as well as vitamins Bj, B12, and E. Work in biological organic chemistry indicated diat hemp plant could be used for production of narcotics. T odd had degrees awarded from Oxford, Frankfurt, and Glasgow, among others. 

Vaish, N.K., Fraley, A.W., Szostak, J.W., McLaughlin, L.W. Expanding the structural and functional diversity of RNA analog uridine triphosphates as candidates for in vitro selection of nucleic acids. Nucleic Acids Res. 28, 3316-3322 (2000). 

The diversity of protein structures has already been mentioned. It is a property of proteins to bind other molecules—water, ions, neutral solutes such as sugars, lipid soluble molecules, other proteins and nucleic acids. Binding sites may be on the surface of the molecule, in a crevice or, with membrane bound proteins, projecting into the extracellular fluid or cytoplasm. Over time, many binding sites have become highly specific, with binding constants > 106 or indeed > 109. The structure of many such sites are now known (Campbell, 1996). 

Indeed, the discovery of catalytic RNA revived the discussion about an RNA world and the question whether polynudeotides or polypeptides were first to evolve [4]. What makes nucleic-add-like molecules so interesting and unique is their inherent capacity to store and to replicate information. These properties, in combination with their structural diversity, makes nucleic acid-like molecules the... 

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