Nucleotide monomer

Nucleic Acids. Nucleic acids are polynucleotides that is, they are condensation polymers of nucleotide monomers. A nucleotide is a three-component system, ie, a combination of a sugar, a phosphate, and a nitrogenous base residue. Adenosine monophosphate is an example ... 

With respect to template-directed syntheses, the syntheses of oligonucleotide using polynucleotide have already been attempted62-69. However, it has not necessarily been successful yet, since the binding constant of the nucleotide monomer with polynucleotide was not large, particularly in aqueous media. 

The ability to detect small genetic changes becomes more difficult as mass increases. There is further an upper mass range where analysis is impractical. For low-resolution instruments this limit is around a 100 mer. Thus the mass has to be minimized or a high-resolution instrument employed. Alternatively, the smaller the piece of DNA analyzed, the more it chemically resembles a primer or nucleotide monomer thus separation of the two during cleanup is difficult to do. If the primers and nucleotides are not removed, they can provide a massive background on MS analysis or inhibit ionization of the PCR product by preferential ionization. Thus for practical reasons it is extremely difficult to employ a PCR product below a 40 to 50mer for direct ESI MS or ESI MS-MS analysis. 

In each nucleotide monomer of DNA or RNA molecules, a phosphate group is attached to the C-5 hydroxyl of each sugar residue in an ester (anhydride) linkage. These phosphate groups in turn are linked in diester bonds to neighboring sugar groups of adjacent nucleotides... 

Use a molecular model kit to build an example of a DNA nucleotide monomer. Join your nucleotide to your classmates nucleotides... 

Figure 13-27 illustrates the two major classes of nucleic acids, distinguished from each other by the MbUKt u.zb type of ribose sugar in the nucleotide monomers. Those without an oxygen... 

Nucleic acid A long polymeric chain of nucleotide monomers. 

Thus DNA may be considered to be built up from nucleotide monomers by esterification of the 3 -hydroxyl group of one nucleotide with the phosphate group of another (Figure 25-21). 

Polymers are large molecules formed by the repetitive bonding together of many smaller molecules, called monomers. As we ll see in the next chapter, biological polymers occur throughout nature. Cellulose and starch are polymers built from small sugar monomers, proteins are polymers built from amino acid monomers, and nucleic acids are polymers built from nucleotide monomers. The basic idea is the same, but synthetic polymers are much less complex than biopolymers because the starting monomer units are usually smaller and simpler. 

The chapter begins with a discussion of the structure of nucleosides and nucleotides. Then the structure of the nucleic acids, DNA and RNA. the polymers formed from nucleotide monomers, is presented. The function of these polymers in the replication, transcription, and translation of genetic information is briefly addressed. Next, the organic chemistry involved in determining the sequence of DNA is presented. Finally, the synthesis of small DNA molecules in the laboratory is discussed. 

First, the question of where nucleotide monomers may have come from is critical. Given that the formose reaction is the most likely candidate for the synthesis of prebiotic ribose, but yields very little pure material, the role of stereoselective catalysts (clays, amino acids, or lipid aggregates) in directing the reaction should be fully explored. In this respect, Wachters-hauser16 has advanced a scheme for nucleotide synthesis based on pyrite catalysis than can be readily tested. 

The repair and replication of cells involves metabolism - interconversions of hundreds of low molecular weight metabolites that ultimately yield the precursors for much larger, more complex macromolecules such as phospholipids (based on phosphatidic. acids or long chain fatty acid esters of glycerol phosphate), polynucleotides such as RNA and DNA (polymers of nucleotide monomers), proteins (polypeptides or amino acid monomers linked by peptide bonds) and polysaccharides (polymers of simple sugars or monosaccharides). 

DNA Synthesis for Nanoconstruction Single strands of DNA, otherwise known as oligomers, are most commonly produced using a solid-support synthesis process [161, 162], This is a cyclic process where each nucleotide is sequentially coupled to form a nucleotide chain (working from the 3 end to the 5 end). The 3 end is initially covalently linked to a solid support and the nucleotide monomers are added sequentially. This is a well-established process and its key parameters and critical process steps are well documented in the literature [163,164],The DNA strands can be tailored according to the desired nanoconstruction scheme and target structure [165]. 

Nucleic acids are polymers constructed from nucleotides (monomers) and found in cell nuclei. 

Nucleic acids are polymers constmcted from nucleotides (monomers), where ribonucleic acid (RNA) comprises ribonucleotides, and deoxyribonucleic acid (DNA) contains deoxyribonucleotides. 

Nucleic acids are composed of nucleotide monomers, which themselves are built from a phosphate group, a sugar, and a nitrogenous base. The bases are of two types, pyrimidines (single ringed) and purines (double ringed). 

The recent revolution in molecular biology has brought with it an increased demand for the efficient chemical synthesis of short DNA segments, called oligonucleotides. The problems of DNA synthesis are similar to those of protein synthesis (Section 26.10) but are more difficult because of the complexity of the nucleotide monomers. Each nucleotide has multiple reactive sites that must be selectively protected and deprotected at the proper times, and coupling of the four nucleotides must be carried out in the proper sequence. Automated DNA synthesizers are now available, however, that allow the fast and reliable synthesis of DNA segments up to 200 nucleotides in length. 

Dihydropyrane appears to be the reagent of choice for blocking the 2 -hydroxy groups of 5 -nucleotide monomers that are to be polymerized. The THP-ethers are usually very sensitive to acids and should be prepared just prior to use or else stored in the dry state at the lowest possible temperature. 

Both starch and cellulose are prepared in nature by enzymatic, chain growth polymerization reactions of glucose nucleotide monomers [6]. In both cases, the monomer precursor is glucose-1-phosphate, which is enzymatically converted to the nucleotide derivative. The latter, in turn, complexes with an enzyme to form the activated monomer at the active site on the enzyme, which also contains the growing polymer molecule, as schematically illustrated below for the enzymatic polymerization of cellulose ... 

As pointed out in section 9.6.5, insertion of 3 -0-(N,N-diisopropylamino)methoxyphos-phine nucleotide monomers and subsequent amidation using 1,5-diaminopentane/iodine leads to aminoalkylated phosphoramidates, which may act as linkers for functional moieties (Fig. 33). 

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