A model of the randomly coiling form of poly(rU) based on minimum‐energy conformers of UpU is described. The blend of conformers is chosen to fit the CC rotational populations derived in nmr studies of UpU and poly(rU) and to match the experimental unperturbed dimensions of the poly(rU) chain. In addition, estimates of loop closure based on the model are comparable to the sizes of loops most frequently seen in model oligonucleotides. Approximately 60% of the conformers constituting the model are characterized by stacked, extended C2′‐endo ω′ωψ = tg−g+ rotations. The remainder of the chain is described by equal numbers of C3′‐endo A (ω′ωψ = g−g−g+) and Watson‐Crick (ω′ωψ = g−tt) helical arrangements.
All Science Journal Classification (ASJC) codes
- Organic Chemistry