Polynucleotide Conjugates

Heller, M. J. Polynucleotides conjugated with chromophores and fluorophores for determination of nucleic acid. PCX Int. Appl. WO 9309128, 1993 Chem. Abstr. 1993, 119, 242929. 

Molecules of DNA and RNA are polynucleotides, polymeric species built from nucleotide units. Polymerization takes place when the phosphate group of one nucleotide (which is the conjugate base of an organic phosphoric acid) condenses... 

The development of DNA sensors and high-density DNA arrays has been prompted by the tremendous demands for innovative analytical tools capable of delivering the genetic information in a faster, simpler, and cheaper manner at the sample source, compared to traditional nucleic acid assays. Nanoparticle-biopolymer conjugates offer great potential for DNA diagnostics and can have a profound impact upon bioanalytical chemistry. Nanoparticle/polynucleotide assemblies for advanced electrical detection of DNA sequences have been reviewed by Wang [145]. 

In addition to the reaction of mercaptopropionic acid, mixed anhydrides were also formed and identified starting from leucine and phenylalanine in the presence of Ca2+ ions, showing that RNAs can replace protein aminoa-cyl fRNA synthetase catalysts for amino acid activation. The formation of a detectable amount of aminoacyl S -phosphalc polynucleotide seems to be in contradiction with the instability predicted for aminoacyl adenylates (Table 1), however it can be explained by the low pH value increasing their stability and the fact that the selected RNA structures are likely to stabilize the mixed anhydride moiety of the covalent conjugate by favorable intramolecular interactions induced by folding. 

How likely is it to have a value matrix fV with pairs of conjugate complex eigenvalues Rumschitzki [8] showed that the value matrix JV can be converted to a symmetric matrix fV by means of a similarity transformation provided the corresponding mutation matrix Q is symmetric (Qij = Qji)-Then all eigenvalue of JV are real. Equal frequency of mutations in both directions, Ij - /j and 7j - Ij, is a realistic assumption unless the polynucleotide sequences under consideration contain so-called hot spots. These are positions at which point mutations are particularly frequent. It is unlikely that the reverse mutation leading to the sequence with the original hot spot is also an unusually frequent event. Therefore we expect a mutation matrix Q lacking symmetry in these cases. 

In experimental studies on the formation of antibodies to a hapten-protein conjugate, it appears that the more immunogenic the protein, the better the response. Although proteins are usually the most efficient carriers, polypeptides, polysaccharides, lipid membranes, or even polynucleotides may be sufficient to impart im-munogenicity. In recent years, direct conjugation of simple chemicals to structural elements of cell membranes (especially of monocytes and macrophages) has been thought to play an important role in the induction of sensitization (de Weck 1975 Shearer 1975). The protein carrier or cell membrane structure of the host may contribute to the specificity of the response (partial autoimmunity). 

The anionic nature of polynucleotides is utilized in the formation of their noncovalent conjugates. Their simple mixing with natural macromolecules, such as chitosan [42] or various cationic artificial polymers [43], leads to the spontaneous noncovalent complex formation that under special conditions can exist as nanoparticles capable for i.v. injections (Fig. 3.35). The lifetime for blood circulation of extracellular DNA molecules in mammalians is in... 

This chapter will introduce polymer systems containing either naturally occurring maaomolecules (polysaccharides, proteins, DNA) or their subunits (bioanalogous molecules, amino acids, short peptides and peptide derivatives, polypeptides, polynucleotides), respectively. The natural building blocks can be connected by covalent bonds or by self-assembly and either can be used alone (see, e.g.. Section 5.4) or in combination with synthetic polymer units (biohybrids). Alternatively the building block itself may be a hybrid of a natural and synthetic molecule (bioconjugate cf. Section 3.5), as, for instance, a PEG-peptide conjugate. 

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