Sugar Modifications

The a-anomeric form of a 2 -deoxyribose, which has the base inverted with respect to the natural P-anomeric form, can be synthesized by using the phosphoramidite method sugar modification renders the derivatives nuclease-resistant. These analogues form parallel duplexes with complementary RNA... 

As biochemical tools, suitable and sensible imino sugar modifications will certainly become helpful intelligent probes and reporters addressing some of the future needs of research in carbohydrate-active enzymes. 

In cases A, B and C, the DNA base or sugar modifications can be introduced via automated solid-phase synthetic methods using suitable DNA building blocks. As an alternative route, DNA modifications can be introduced by solid-phase methods which are applied during or after the complete automated solid-phase synthesis, as is the case for the preparation of the DNA assays B and D. 

Acyclic sugar modifications derived from L-threoninol and L-serinol (60) have been incorporated into ODNs for hybridisation studies. The presence of the acyclic sugar, as expected, causes some destabilisation to the duplex, though the extent of destabilisation is dependent on sequence and the number of modifications. 

A. Rosenthal and S. N. Mikhailov, Branched-chain sugars. Modifications in the reaction of l,2 5,6-di-0-isopropylidene-oi-D-ribo-hexofuranos-3-ulose with Giignard and oiganolithium reagents, J. Carbohydr. Nucleosides Nucleotides 6 237 (1979). 

Structures of the Open-chain Forms of Reducing Sugars modification (equation 1.11) does not suffer from this flaw. 

Anhydrohexitol nucleic acid) (Cyclohexene nucleic acid) Locted nucleic add Figure 5.8. Some new sugar modifications. 

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