Deoxyribonucleic acid phosphate esters

Nucleic acids are acidic substances present m the nuclei of cells and were known long before anyone suspected they were the primary substances involved m the storage transmission and processing of genetic information There are two kinds of nucleic acids ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) Both are complicated biopolymers based on three structural units a carbohydrate a phosphate ester linkage between carbohydrates and a heterocyclic aromatic compound The heterocyclic aro matic compounds are referred to as purine and pyrimidine bases We 11 begin with them and follow the structural thread... 

Phosphate esters play a central role in biochemistry. Figure 11-3 shows how phosphate ester linkages compose the backbone of the nucleic acids RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). These nucleic acids, which carry the genetic information in the cell, are discussed in Chapter 23. 

Several structurally and mechanistically distinct classes of catalytic RNAs have been discovered (Altman 1990 Cech 1990 Pace and Smith 1990). Generally, for catalytic RNA reactions reported thus far, RNA and deoxyribonucleic acid (DNA) are substrates and transesterification or hydrolysis of phosphate esters are the reactions catalyzed (Piccirilli et al. 1992). However, binding of amino acids, organic dyes, and other small molecules to RNA suggest that catalytic RNAs may catalyze other reactions (Prudent et al. 1994). Some catalytic RNA molecules are metalloenzymes and require magnesium for their three-dimensional structure and catalytic activity. Like... 

Nucleic acids are polynucleotides in which a phosphate ester unit links the 5 oxygen of one nucleotide to the 3 oxygen of another. Figure 27.22 is a generalized depiction of the structure of a nucleic acid. Nucleic acids are classified as ribonucleic acids (RNA) or deoxyribonucleic acids (DNA) depending on the carbohydrate present. 

Phosphates play an enormously important role in biological systems. The genetic substances deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are phosphate esters (see Figure 9.11). Bones and teeth are constructed from collagen (fibrous protein) and single crystals of hydroxyapatite, Ca5(0H)(P04)j. Tooth decay involves acid attack on the phosphate, but the addition of fluoride ion to water supplies facilitates the formation of fluoroapatite, which is more resistant to decay. 

The structure and properties of nucleic acids are affected and inherited from the general stracture characteristics of their monomer molecules and nucleotides (Blackburn and Gait, 1996 Harmon et al, 1978 Saenger, 1984). Nucleotides are the phosphate esters of nucleosides, which are components of both ribonucleic add (RNA) and deoxyribonucleic acid (DNA). All nucleotides are constructed from three components ... 

The mineral phosphate, apatite, is the most abundant and widespread phosphorus compound on earth and phosphoric acid is the most important industrial conunodity based on phosphorus. However, the organic phosphate ester known as deoxyribonucleic acid (DNA), is present in aU life forms and lies at the very heart of biochanistry and genetics. It is the most frequently studied phosphorus compound and is probably the most crucial phosphorus compound as far as the survival and... 

Many of the simple trioses, tetroses, and pentoses do not occur naturally in the free state but are commonly found as phosphate-ester derivatives. The phospho-esters are important intermediates in the breakdown and synthesis of carbohydrates by living organisms. D-Glucose is converted into D-fructose-l,6-bisphos-phate that is then cleaved in half to give D-glyceraldehyde-3-phosphate and dihydroxy acetone phosphate (see Chapter 11). D-Erythrose is found as the 4-phosphate in the pentose-phosphate pathway of carbohydrate degradation and in the photosynthetic process. D-Ribose-5-phosphate, D-ribulose-5-phosphate, D-xy-lose-5-phosphate, and D-xylulose-5-phosphate are found in the pentose phosphate pathway as well as in the photosynthetic pathway (see Chapter 10). D-Ribulose-1,5-bisphosphate is the direct intermediate to which CO2 is added in the photosynthetic pathway. D-Ribose-5-phosphate also is the precursor of RNA (ribonucleic acid) and DNA (deoxyribonucleic acid). See Fig. 1.7 for the structures of these common sugar phosphates. 

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