Oligonucleotide systems

N. Windhab, R. Micura, M. Stanek, B. Jaun, and A. Eschenmoser, Pentopyranosyl oligonucleotide systems. 9th Communication, Helv. Chim. Acta, 86 (2003) 4270-4363. 

Such a capability of an oligonucleotide system deserves special attention in the context of the problem of the origin of biomolecular homochirality breaking molecular mirror symmetry by de-racemization is an intrinsic property of such a system whenever the constitutional complexity of the products of co-oligomerization exceeds a critical level. 

Chirality Induced Through Association with Oligonucleotide Systems... 

Schoning K, Scholz P, Guntha S, Wu X, Krishnamurthy R, Eschenmoser A. Chemical etiology of nucleic acid structure the alpha-threofuranosyl-(3 ->2 ) oligonucleotide system. Science 2000 290 1347-1351. 

Schbning, K.-U., et al. (2000). Chemical etiology of nucleic acid structure the Q -threofuranosyl-(3 -x T oligonucleotide system. Science, 290, 1347-51. 

In order to facilitate entry into a wide variety of artificial oligonucleotide systems, electrophilic synthons 3 and 4 were developed. Both compounds have their exo-cyclic amino group protected as the benzamide. This not only protects this functionality, but also improves the solubility of the heterocycles in organic solvents. Moreover, because both incorporate a reactive electrophilic functionality. 

Kinetic analysis of the experimental data gave rise to a p value of 0.63, which is slightly higher than in oligonucleotide systems. This finding suggests that self-replicators suffer less from product inhibition on the basis of peptides... 

A comprehensive experimental involvement in the problems of a chemical etiology of the nucleic acids structure would require a systematic extension of the study into hexo- and pentopyranosyl (as well as hexo-and pentofuranosyl) oligonucleotide systems which have their phospho-diester link between positions other than the (6 4 )- or the (5 -> 3 )-... 

Figure 40. Arrows indicate sources of severe stoic hindrance which hamper base pairing in hexopyranosyl oligonucleotide systems.

Figure 44. All hexi ynuiosyl oligonucleotide systems investigated so ar (cf. lecture 1) have their (rfiosphodiestor groups between the position C-6 and C-4 of the hexopyranose units.

Figure 45. Survey of ttie constitutions of (formally) conceivable oligonucleotide systems derived firom aldohexoses and aldopentoses, and predictions about their pairing propensities.

Figure 49. Constitution and configuration of the ribopyranosyI-(4 -> 2 )-oligonucleotide system ( Ribopyranosyl-RNA", p-RNA ) [17].

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