Right-handed DNA

Figure 1 Examples of chiral metallointercalators that bind DNA with little site selectivity (above) and with high specificity for the targeted sites shown (below). In the center is shown schematically the basis for enantiomeric discrimination in stacking in the right-handed DNA helix. For the A-isomer, the ancillary ligands have a right-handed orientation in the DNA groove, whereas for the left-handed A-isomer, steric clashes between the ancillary ligands and phosphate backbone can develop.

On the other hand, it has also been shown that interconversion between A- and A-enantiomers of [Fe(phen)3] " " occurs easily and the A-isomer is enriched upon complexation of rac-[Fe(phen)3] " " with a right-handed DNA double helix.This behaviour, known as the Pfeiffer effect, was also observed when the same iron complex rac-[Fe(phen)3] " ", which is configurationally labile, was bound to the optically active species such as A-TRISPHAT (4.7) or the heptaanion modified cyclodextrin (4.12) (see Sections 4.1.3 and 4.2). 

In silver plated DNA, the double helices are surrounded by a sheath of metal atoms to which they are covalently linked [119]. Left-handed DNA can be wound around right-handed DNA [120,121], The unravelling of lipid metabolism with DNA microarrays has proceeded, and RNA microarrays may prove useful for therapy [122,54],... 

Interactions between DNA and metal complexes are the basis for the use of square-planar platinum(ll)-containing anti-cancer dmgs. (a) Explain how the interaction of right-handed DNA with chiral complexes leads to diastereoisomeric species. 

Would you like left- or right-handed DNA with your drug ... 

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