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Kwasy nukleinowe jako katalizatory reakcji chemicznych

Bukowiecka-Matusiak M., Sobczak M.

Wiadomości Chemiczne

2012

[Z] 66, 1-2

119-137

Nucleic acids, due to their specific structure, are effective and durable carriers of genetic information. They have also been used as catalysts in chemical reactions. The right-handed DNA double helix structure has become one of the icons of modern science, and its share in asymmetric catalysis is undeniable. In these reactions, DNA is a source of chirality and proximity between oligonucleotides and complexes of copper during catalysis, what allows a direct transfer of chirality from DNA to the reaction product. Almost complete regioselectivity and excellent enantioselectivity of the aforementioned reactions in water are the evidence of the potential of asymmetry based on DNA. Asymmetric catalysis used in organic synthesis, allows achieving high enantioselectivity. This strategy has been successfully used to create new C-C bonds in Diels- Alder cycloaddition, Friedel-Crafts alkylation and Michael addition using copper complexes with oligonucleotides as catalysts. The important factor to optimize the reaction of asymmetric catalysis in the presence of DNA constitutes its sequence. It has been shown that the use of the double helix DNA can provide the product with higher enantiomeric excess than using the single strand of DNA. In addition, the results of the study suggest that Friedel-Crafts alkylation is accelerated by DNA almost 30-fold. The same correlation is observed in Diels-Alder cycloaddition. Due to promising results, further testing directed at the possibility of using catalytic DNA is being conducted.

Perspektywy stosowania metody blokowej do syntezy modyfikowanych oligonukleotydów w roztworze i na stałym podłożu

Bukowiecka-Matusiak M., Ziemecka I.

Wiadomości Chemiczne

2009

[Z] 63, 1-2

63-83

Studies on properties and function of nucleic acids constitute the most fascinating cognitive area in biology, chemistry and medicine. Dynamic development of the required techniques, primarily Nuclear Magnetic Resonance (NMR) [4], or crystallization techniques, allowed to obtain a detailed information about structural diversity of complicated biological compounds, for example peptides and nucleic acids. The replacement of one of the nonbonding oxygens of internucleotide bond by sulfur, selenium, methyl or other functionalized alkyl groups creates a stereogenic centre at the modified phosphorus atom [16]. This arises a question about availability of stereoregular, P-defined analogues of DNA and RNA. Short synthetic oligonucleotides are indispensable tools in biomolecular and structural studies [5, 6]. They also have potential as therapeutics [13, 14] for manipulation of genes expression in a sequence specific manner. The block synthesis assuming incorporation of P-chiral, diastereomerically pure dimeric building blocks is attractive, reliable and patent for automated approach to the synthesis of "chimeric oligonucleotides", both in solution and on solid support [23]. The attention of researches turned toward chimeric constructs of 16 containing, in successive internucleotide positions, phosphates and methanephosphonates. Reynolds et al. [34] found that for therapeutic applications, only chimeric oligonucleotides 16 with incorporated RP-dinucleoside methanephosphonates had acceptable binding affinity towards complementary template of DNA and RNA. Isosequential chimeric oligomers, constructed either from diastereomeric mixtures of dinucleoside methanephosphonates, or from those with SP-configuration, form less stable duplexes with the same complementary RNA templates. The preparation of the aforementioned chimeras utilized a "dimeric building blocks" approach [23]. The corresponding dinucleoside (3',5')-methanephosphonates 17 were separated into diastereomers by chromatographic methods. After removal of the 3'-O-protecting group, the required RP-isomers were activated at the 3'-O-position, and used as such for condensation via the phosphoramidite method [25]. Attempts towards their P-epimerization and recycling have failed. Such situation was notwithstanding the requirement of a cost-effective synthesis of new potential therapeutics. Therefore, Stec et al. [36-38], and efforts were undertaken in the design of a cost-effective synthesis of RP-dinucleoside (3',5')-methanephosphonates 17.