Strand analogues, polynucleotide

Polynucleotide Strand-Analogues The following polymers (Tables I and II) were prepared by AIBN- or -ray induced (Laboratory Radiation Unit RCH-y-30 as a 60co -source) polymerization and copolymerization reactions, respectively, followed in case of (vA, IvOH]q 7)p by a polymeranalogous reaction. The starting amounts of N-vinylnucleobases and their comonomers were adjusted to yield a nearly l l-ratio in the copolymers. 

Modelling and "Strangening" Nucleic Acids by Polynucleotide Strand-Analogues... 

Figure 36. CPK illustration of the hypothetical (C)n (vH,vCOO )n hybrid compared with the all-polynucleotide base-paired (C)n (I)n> vizualizing the hydrogen-bonding and stack similarities between the polynucleotide/mutual strand-analogue hybrid and the...

Figure 45. Effects of some polynucleotide strand analogues in an in vitro AMV-revertase assay (RNA-dependent DNA polymerase endogenous template-primer combination) (70). Assay pH 8.0 50 mM Tris-HCl 2 mM DTT 5 mM Mg 1 mM Mn -50 mM NaCl 0.2 mM dBTPs 10 fiC H-TTP T = 37°C.

Hoffmann,S..Witkowski,W.."Polynucleotide Strand-Analogues" and "Base-Pair Analogues" in Conf,Proc. "Wirkungsmechanismen von Herbiciden und syntheti-schen Wachstumsregulatoren" 1972,RGW-Symp,Halle/S.. GDR... 

Especially attractive was the possibility to connect nucleosides, as has been realized, for instance, with the hexathymidine 141 and with the elongated and alternating strands 142 and 143. These compounds represent artificial oligonucleosides, which may interact with natural polynucleotides or nucleic acids. On treatment with Cu(i), 142 and 143 gave the double-helical complexes 144 and 145, respectively, inside-out analogues of double-stranded nucleic acids, which may be termed deoxy-... 

Another variation of the classical primary polynucleotide structure (10.90a) was established by the synthesis of derivatives based on hexose rings (10.92b). The use of the latter in place of ribose rings produces a more linear chain which forms a non-helical double-stranded arrangement. However, some of these polyhexose chains appear to form double-stranded arrangements more stable than duplex DNA built from (10.92a). Similarly for RNA analogues [62]. 

Several additional results have arisen from these studies. Polynucleotides can not only form Watson-Crick helical double-stranded complexes but may also form helical structures between themselves which can have more than two strands, as well as non-Watson-Crick base pairs, like the complex poly(l) poly(A)-poly(l). Furthermore, numerous polymers of base and sugar analogues have been prepared and studied. 

Anti-poly G poly C antibodies have been demonstrated by immunodiffusion and by complement fixation in the sera of rabbits immunized with poly G-poly C — MBSA (Michelson et al., 1971 Nahon-Merlin et al., 1971). The anti-poly G poly C antibodies react not only with poly G poly C but also with a large number of double-helical complexes such as poly A poly U, poly I poly C and poly dG poly dC. It is nevertheless to be noted that the complex poly A poly I in which two purine polynucleotides are involved is not precipitated by these antibodies, which is readily explained by the special stereochemical structure of this complex. The anti-poly G poly C antisera nevertheless precipitate poly iso A poly I, but in this case it can be considered that displacement of the glycosyl-hnkage from N to in polyisoadenylic acid converts this polynucleotide into an analogue of poly C. The complex is thus effectively between a poly purine ribonucleotide and a poly pyrimidine ribonucleotide as in the case of other complexes such as poly A poly U and poly I poly C. Immune sera against poly G poly C also react with the triple-stranded complex 2 poly G poly C. In addition they can precipitate one or the other of the component polynucleotides of the homologous complex. 

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