Figure 1.

(a) Domain map of human U2AF⁶⁵ showing the limits of RRM1 and RRM2. UHM (U2AF homology motif) is a protein-interaction domain (Gozani et al., 1998 ▶) and RS denotes an arginine/serine-rich domain. The RRM1–RRM2 linker is expanded to show a phylogenetic sequence comparison. Residues that are conserved in at least four of the five species shown are indicated in bold. (b) Variants of the linker region (residues 228–258) between human U2AF⁶⁵ RRM1 and RRM2 used for cocrystallization with oligonucleotides. Dashes and numbers in parentheses indicate deleted residues. The ‘d8-linker’ variant is derived from the linker sequence of splicing factor Sex-lethal (‘s-­linker’). The successfully cocrystallized variant is shown in bold.