Protein and Nucleic Acid Synthesis

All of the genetic information in the cell is called the genome. Every time a cell divides, the information in the genome is copied and passed on to the new cells. This replication process must duplicate the genetic instructions exactly. Some sections of DNA called genes contain the information to make a particular protein. 

When a cell requires protein, another type of nucleic acid, ribonucleic acid (RNA), interprets the genetic information in DNA and carries that information to the ribosomes, where the synthesis of protein takes place. However, mistakes may occur that lead to mutations that affect the synthesis of a certain protein. 

Identifying the Primary, Secondary, Tertiary, and Quaternary Stmctures of Proteins (16.3, 16.4) 

Describe the bases and ribose sugars that make up the nucleic acids DNA and RNA. 

The nitrogen-containing bases in nucleic adds are derivatives of pyrimidine or purine. 

2 (a) The nucleosides have an iV-glycosidic linkage diat (like an (9-glycosidic linkage) is rapidly hydrolyzed by aqueous acid but is one that is stable in aqueous base. 

4 (a) The isopropylidene group is part of a cyclic acetal and is thus susceptible to hydrolysis by mild acid. 

14 Ionization of the benzoyl gronp at the anomeric carbon (Cl) is assisted by the carbonyl oxygen of the C2 benzoyl gronp, resnlting in a stabilized cation blocked from attack on the a-face. 

l Analysis of the molecular formula C5H10O indicates an IHD = 1. Structural possibilities are a C=C, a C=0, or a ring. 

Two CH3CH2 groups must be present, with the CH3 giving rise to the signal at 5 10 and the CH2 giving the signal at S 37. 

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Dacarbazine is activated by photodecomposition (chemical breakdown caused by radiant energy) and by enzymatic N-demethylation. Formation of a methyl carbonium ion results in methylation of DNA and RNA and inhibition of nucleic acid and protein synthesis. Cells in all phases of the cell cycle are susceptible to dacarbazine. The drug is not appreciably protein bound, and it does not enter the central nervous system. 

Hall IH, Liou YF, Lee KH. Antitumor agents LII The effects of molephantinin on nucleic acid and protein synthesis of Ehrlich ascites cells. J Pharm Sci 1982 71 687-690. 

It should already be clear from what has been stated that a great diversity of viruses exist. It should therefore not be surprising that there is also a great diversity in the manner by which virus multiplication occurs. Interestingly, many viruses have special features of their nucleic acid and protein synthesis processes that are not found in cells. In the present chapter, we are only able to present some of the major types of virus replication patterns, and must skip some of the interesting exceptional cases. 

Volume XX. Nucleic Acids and Protein Synthesis (Part C)... 

We consider, successively, the catalytic role of several classes of mononuclear Zn2+ enzymes and then discuss enzymes with di- and tri-nuclear cocatalytic zinc centres, some of which include a metal ion other than zinc. We conclude with a presentation of some of the zinc-based motifs found in proteins involved in the regulation of nucleic acid and protein synthesis. 

Casiano Torres, C. A. and Baez, A. 1986. Effects of the antitumor drugs 3-nitrobenzothiallozo[3,2-a]quinolium and fagaronine on nucleic acid and protein synthesis. Biochemistry and Pharmacology, 35 679-685. 

Viruses are obligate intracellular parasites that use many of the host cell s biochemical mechanisms and products to sustain their viability. A mature virus (virion) can exist outside a host cell and still retain its infective properties. However, to reproduce, the virus must enter the host cell, take over the host cell s mechanisms for nucleic acid and protein synthesis, and direct the host cell to make new viral particles. 

Mycelial growth is more sensitive to cymoxanil than early growth phases, including the release of zoospores from sporangia and their germination. Cymoxanil inhibits nucleic acid and protein synthesis in some fungi but may have to be activated to induce a fungicidal response. 

Antibiotics as Inhibitors of Nucleic Acid and Protein Synthesis G. Hartmann et al., Angew. Chem., Int. Ed. Engl., 1968, 7, 693-701. 

M. Goodman and F. Morehouse, Organic Molecules in Action, Gordon and Breach, New York, 1973. See, for example, the chapters on prebiotic synthesis, origin of the cell, nucleic acids, and protein synthesis. 

Low activities of orotidine phosphate decarboxylase and (usually) orotate phosphoribosyltransferase are associated with a genetic disease in children that is characterized by abnormal growth, megaloblastic anemia, and the excretion of large amounts of orotate. When affected children are fed a pyrimidine nucleoside, usually uridine, the anemia decreases and the excretion of orotate diminishes. A likely explanation for the improvement is that the ingested uridine is phosphorylated to UMP, which is then converted to other pyrimidine nucleotides so that nucleic acid and protein synthesis can resume. In addition, the increased intracellular concentrations of pyrimidine nucleotides inhibit carbamoyl phosphate synthase, the first enzyme in the. naibwav of aro-tate synthesis. 

Zinc 2-3 g 15 mg > 160 enzymes in main metabolic pathways, nucleic acid and protein synthesis, immune system Occurs in Iran, Egypt TPN, genetic disease, traumatic stress growth depression, delayed sexual maturation, skin lesions, depression of immunocompetence, change of taste acuity Unlikely except from prolonged therapeutic use can interfere with Fe and Cu metabolism... 

Mechanism of Action. Pyrimethamine blocks the production of folic acid in susceptible protozoa by inhibiting the function of the dihydrofolate reductase enzyme. Folic acid helps catalyze the production of nucleic and amino acids in these parasites. Therefore, this drug ultimately impairs nucleic acid and protein synthesis by interfering with folic acid production. The action of sulfadoxine and other sulfonamide antibacterial agents was discussed in Chapter 33. These agents also inhibit folic acid synthesis in certain bacterial and protozoal cells. 

Higgins, T. J. V. Zwar, J. A. Jacobsen, J. V. Hormonal control of the level of translatable mRNA for barley aleurone layers. In Nucleic Acids and Protein Synthesis in Plants, Ed. J. H. Well L. Bogorad, Paris ... 

As discussed earlier, there are a number of ways by which an antibiotic can selectively interfere with biochemical processes in a microbe. This part of the chapter deals in more detail with the respective mechanisms. These include the cell wall and membrane, nucleic acid and protein synthesis, and intermediary metabolism. 

Anti-viral drugs use mechanisms that interfere with nucleic acid and protein synthesis, inhibiting their attachment to and penetration of host cells. Because the viruses frequently adapt their structures, their elimination is difficult. A research team in Cambridge19 are looking at what they call a mutator protein . This protein is made by our own cells and is released to sneak inside certain viruses and cause chaos and mutations in their genome. Unfortunately the AIDS virus has evolved a defence against this process, but it is useful for other viruses. 

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