Nucleobase sequence guided reactions in non-aquaeous media
It has been found that PNA duplexes
(in contrast to DNA duplexes) show significant stability in the
presence (>60%)
of organic solvents such as dioxane or dimethyl formamide, and from
extrapolation of the results it is inferred that PNA duplexes may be
stable in aprotic, non-polar, organic solvents. Thus nucleobase
sequence guided reactions and (self) assembly processes for use in
non-aqueous environments may be developed based on PNA sequence
recognition. This may lead to novel self-assembly systems,
nano-structures
and chemical selection processes in organic solvents, not previously
accessible for these type of molecular recognition.
For instance one could imagine PNA oligomers which due to sequence
composition may function as electron relays in photochemical electron
transfer systems (e.g. based on transition metal complexes). Also PNA
aptamers which upon complexation with transition metal ion redox pairs
(such as Cu+/Cu++, Fe2+/Fe3+ and in particular Ru2+/Ru3+) activate
these systems for photochemical excitation could play a role as
“metabolic chaperones”, and thereby constitute the genetic-function
link required for selective evolution, Fig .1.
Figure 1: Schematic drawing of template directed ligation of a PNA beacon that is formed upon ligation, and which will produce a FRET (F1/F2 fluorophore pair) signal upon dissociation from the template due to hairpin stabilization. If in addition, the sequence in the hairpin loop could be used e.g., to activate photochemical excitation as “metabolic chaperone”, and thereby constitute the genetic-function link required for selective evolution.