Figure 1.

Conformational states detected by NMR for the MoMuLV Ψ^CES site. (a) Unspliced MoMuLV genome showing the location of Ψ^CES. (b) Secondary structures of the monomeric Ψ^CES site. DIS-2 and SL-C exist in two alternate conformations (the palindromic sequence is shown in green, and conserved GACG sequences required for kissing interactions are shown in blue). (c) Secondary structure of the dimeric core encapsidation signal ([Ψ^CES]₂). A frame shift upon dimerization exposes UCUG elements (red) that can function as potential NC binding sites.