Deoxyribonucleic acid biosynthesis

The nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), are the chemical carriers of a cell s genetic information. Coded in a cell s DNA is the information that determines the nature of the cell, controls the cell s growth and division, and directs biosynthesis of the enzymes and other proteins required for cellular functions. 

The nucleic acids play a central role in the storage and expression of genetic information (see p. 236). They are divided into two major classes deoxyribonucleic acid (DNA) functions solely in information storage, while ribonucleic acids (RNAs) are involved in most steps of gene expression and protein biosynthesis. All nucleic acids are made up from nucleotide components, which in turn consist of a base, a sugar, and a phosphate residue. DNA and RNA differ from one another in the type of the sugar and in one of the bases that they contain. 

Relatively recently Fe/S proteins have been found to function in the regulation of biosynthesis. This can be by promoting deoxyribonucleic acid (DNA) transcription, e.g. the [2Fe-2S] containing Escherichia coli superoxide-activated (SoxR) transcription activator [10-12], or the presumably [4Fe-4S]-containing E. coli transcription factor fumarate nitrate reduction (FNR) [13,14], Alternatively, the Fe/S protein can act by interference with messenger ribonucleic acid (mRNA) translation, i.e., the iron regulatory proteins (IRPs) [15,16], These interactions are stoichiometric, therefore not catalytic. Presumably, they are also a form of sensoring, namely, of oxidants and/or iron [17],... 

Deoxyribonucleic acid is the genetic material such that the information to make all the functional macromolecules of the cell is preserved in DNA (Sinden, 1994). Ribonucleic acids occur in three functionally different classes messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA) (Simons and Grun-berg-Manago, 1997). Messenger RNA serves to carry the information encoded from DNA to the sites of protein synthesis in the cell where this information is translated into a polypeptide sequence. Ribosomal RNA is the component of ribosome which serves as the site of protein synthesis. Transfer RNA (tRNA) serves as a carrier of amino acid residues for protein synthesis. Amino acids are attached as aminoacyl esters to the 3 -termini of the tRNA to form aminoacyl-tRNA, which is the substrate for protein biosynthesis. 

In the form of deoxyribonucleic acid (DNA), the macromolecular nucleic acids are of prime importance in biology because they carry the building plan for each living individual. They are identically reduplicated and inherited from one generation to the next, be it bacterium, plant, animal, or man. The information about every feature of and about every molecule contained in a living being is encoded in the nucleotide sequence of its DNA, which is read out and translated into the amino acid sequences of its proteins. In the many different steps involved in this protein biosynthesis, information transfer takes place which would be impossible without the weak hydrogen bonds. Because they can easily and rapidly be formed and broken, they are ideally suited for these dynamic processes which are so important for life. 

Kornberg s work on the biosynthesis of deoxyribonucleic acid has shown that enzymes in Escherichia coli extracts catalyze the formation of the 5-triphosphates of 2-deoxyadenosine, 2-deoxyguanosine, 2-deoxycyti-dine, and thymidine from the corresponding monophosphates in the presence of adenosine 5-triphosphate, but fail to catalyze phosphorylation of deoxyuridine 5-phosphate this finding could explain why uracil is not a constituent of deoxyribonucleic acid. 

One of the major achievements in all of science has been the identification, at the molecnlar level, of the chemical interactions that are involved in the transfer of genetic information and the control of protein biosynthesis. The substances involved are biological macromolecnles called nucleic acids. Nucleic acids were isolated over 100 years ago, and, as their name implies, they are acidic substances present in the nuclei of cells. There are two major kinds of nucleic acids ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). To understand the complex structure of nucleic acids, we first need to examine some simpler substances, nitrogen-containing aromatic heterocycles called pyrimidines and purines. The parent substance of each class and the numbering system used are shown ... 

Nucleic acids are polymers of nucleotides ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). Although nucleic acids do not survive for geological periods in sediments (the maximum appears to be c.50kyr under favourable conditions) they are very important they control the self-replication of organisms (and hence provide information on evolutionary relationships) and act as the templates for protein biosynthesis. There are four nitrogen-containing bases... 

Another important biological reaction shown to involve a radical intermediate is the conversion of a ribonucleotide into a deoxyribonucleotide. The biosynthesis of ribonucleic acid (RNA) requires ribonucleotides, whereas the biosynthesis of deoxyribonucleic acid (DNA) requires deoxyribonucleotides (Section 27.1). The first step in the conversion of a ribonucleotide to the deoxyribonucleotide needed for DNA biosynthesis involves abstraction of a hydrogen atom from the ribonucleotide to form... 

Bekesi, J. G., Bekesi, E., and Winzler, R. J. Inhibitory effect of o-glucosamine and other sugars on the biosynthesis of protein, ribonu cieic acid, and deoxyribonucleic acid in normal and neoplastic tissues. J. Biol. Chem., 244 3766-3772,1969. 

Smellie, R.M., Gray, E.D., Keir, H.M., Richards, J., Bell, D., Davidson, J.N. Studies on the biosynthesis of deoxyribonucleic acid by extracts of mammalian cells. III. Net synthesis of polynucleotides. Biochim. biophys. Acta (Amst.) 37, 243-250 (1960)... 

The reduction of ribonucleic acids (RNAs) to form deoxyribonucleic acids (DNAs) is the first committed step in the biosynthesis of DNA ... 

Saponin astramembrainin I at a dose of 10 mg/kg i.v. injected into rabbits induced accumulation of cAMP in plasma, affected deoxyribonucleic acid (DNA) biosynthesis in hepatectomized mice and increased incorporation of H-thymidine into regenerating mouse liver [19]. These effects meet many of the requirements of an adaptogen. 

P. Reichard, Z. N. Canellakis, and E. S. Canellakis, Studies on a possible regulatory mechanism for the biosynthesis of deoxyribonucleic acid,/. Biol. Chem. 236, 2514 (1961). 

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