Nucleic acids protein syntheses

Hall IH, Liou YF, Okano M, Lee KH 1982 Antitumor agents 46 In vitro effects of esters of brusatol, bisbrusatol, and related compounds on nucleic acid protein synthesis of P-388 Lymphocytic leukemia cells. J Pharm Sci 71 345-348... 

The classification of these dmgs as antimetaboHtes stems from the mode of action as antagonists to the natural metaboHc processes leading to either DNA, RNA, or proteiu synthesis (13) (see Nucleic acids Proteins). They either inhibit function of a key en2yme involved in protein synthesis or are recmited into the cell division process as DNA synthesis terrninators. For example, methotrexate (8) is a foHc acid [59-30-3], antagonist and... 

Viral replication consists of several steps (Figure 49-1) (1) attachment of the vims to receptors on the host cell surface (2) entry of the virus through the host cell membrane (3) uncoating of viral nucleic acid (4) synthesis of early regulatory proteins, eg, nucleic acid polymerases (5) synthesis of new viral RNA or DNA (6) synthesis of late, structural proteins (7) assembly (maturation) of viral particles and (8) release from the cell. Antiviral agents can potentially target any of these steps. 

The bottom-up synthesis of metallic nanowires was further applied to construct a nanotransistor device.93 The sequence-specific winding of the homologous nucleic acid carried by the RecA-protein into the duplex DNA was used to address the nucleic acid/protein complex on the DNA scaffold (Fig. 12.27). The subsequent association of the anti-RecA antibody to the protein DNA complex, followed by the association of the biotinylated antiantibody, and the linkage of streptavidin-modified carbon nanotube deposited the tubes in the specific domain of the DNA scaffold. The further... 

Adapting techniques based on in vitro protein synthesis to the isolation of enzymes requires establishing a link between a nucleic acid-protein complex and product formation. Methods based on binding, analogous to those developed for phage displayed libraries, may be used to enrich catalysts from noncatalysts. In addition, Tawfik and Griffiths (1998) exploited the aqueous core of reverse micelles as artificial compartments... 

Among the long-chain proline-rich AMPs, diptericin that is carrying post-translational modifications (C-terminal amidation and two O-glycosylations, see for details the previous section of this chapter) has a controversial mode of action. It was shown to disrupt the bacterial membrane, but it is unlikely that it acts primarily as a pore-former, rather it is expected to target metabolic processes such as nucleic acid, protein, and cell wall synthesis [98]. 

Protein synthesis is an extraordinarily complex process in which genetic information encoded in the nucleic acids is translated into the 20 amino acid alphabet of polypeptides. In addition to translation (the mechanism by which a nucleotide base sequence directs the polymerization of amino acids), protein synthesis can also be considered to include the processes of posttranslational modification and targeting. Posttranslational modification consists of chemical alterations cells use to prepare polypeptides for their functional roles. Several modifications assist in targeting, which directs newly synthesized molecules to a specific intracellular or extracellular location. 

The life of a cell depends on thousands of chemical interactions and reactions exquisitely coordinated with one another in time and space and under the influence of the cell s genetic instructions and its environment. How does a cell extract critical nutrients and information from its environment How does a cell convert the energy stored in nutrients into work (movement, synthesis of critical components) How does a cell transform nutrients into the fundamental structures required for its survival (cell wall, nucleus, nucleic acids, proteins, c3Aoskeleton) How does a cell link Itself to other cells to form a tissue How do cells communicate with one another so that the organism as a whole can function One of the goals of molecular cell biology Is to answer such questions about the structure and function of cells and organisms In terms of the properties of Individual molecules and Ions. 

In the cytoplasm, the acetyl moiety of acetyl-CoA can enter the reactions of fatty acid synthesis or lipogenesis. As with other biosynthetic processes, this pathway involves the energy-dependent sequential addition of activated precnrsors to a growing molecule but in contrast to nucleic acid, protein, and glycogen synthesis, lipogenesis also reqnires redncing equivalents. 

In the cell, nucleic acids are involved in the storage of genomic information and the production of proteins. However, other functions of nucleic acids, especially RNA, have been discovered. For example, ribosomal RNAs not only fold the structure of the ribosome but play an important role in protein synthesis (Moore and Steitz, 2002), and the RNA-induced silencing complex (RICS) is composed of a guide strand of siRNA or microRNA and proteins to control gene expression through RNA interference (Filipowicz, 2005). Those RNAs and proteins work cooperatively to achieve complicated tasks. This means that if we could engineer a nucleic acid-protein complex, we could construct more functional biosensor systems. 

The molecules of biological organisms fall into four groups proteins, carbohydrates, nucleic acids, and lipids (nonpolymaic materials soluble in organic solvents, such as fats and oils). Proteins and nucleic acids, and many carbohydrates, are polymers. In this chapter, we will limit our discussion to proteins and nucleic acids. Proteins are the basic constituents of living organisms we discuss these substances in the next section. Nucleic acids are important in the synthesis of proteins we discuss these in the final section of the chapter. 

In this section we consider the two types of biochemical polymers that are most universally characteristic of living things proteins and nucleic acids. Proteins serve structural and catalytic functions in biochemical systems nucleic acids serve functions in protein synthesis and in reproduction. 

Nucleic acid-directed synthesis may have also been important in early peptide formation. Weber and Orgel showed that when the amino acid glycine is esterified to derivatives of adenosine (in the same manner that amino acids are bonded to tRNA in extant protein synthesis), the amino acids will form peptide bonds, resulting in cyclic Gly-Gly dipeptides [29]. Further, when poly-uracil (poly(U)) is added to the mixture, the amount of cyclic Gly-Gly formed increases about 3 times [30]. The temperature and concentration effects of the reactions suggested dependence on formation of a poly(U) hehx specifically, a triple helix of two strands of poly(U) complexed with the glycine-esterified adenosine derivatives. While the exact mechanism of peptide bond formation in this case has not been established, the increased yield of dipeptide could be due to increased local concentration/ optimal orientation of the glycine derivatives based on specific interactions between poly(U) and adenosine. 

The field claimed by molecular biologists is essentially that of nucleic acids, protein structure and synthesis, genetics. The use of drugs in this field is of great theoretical and practical interest. But fundamental pharmacology cannot be limited to this aspect. 

Synthesis of Proteins. From the available pool of free amino acids, proteins are synthesized. The synthesis requires ATP and specific nucleic acids as cofactors and as templates. This is the place where hereditary factors (deoxyribonucleic acids) take effect, since they bear the information for the structure of the proteins (including enzyme proteins). This information is transcribed to messenger RNA which then adheres to ribosomes and serves as the template for the lining-up of activated amino acids. Protein synthesis is one of the most important energyconsuming processes. 

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