FIG. 5.

(A) Three-dimensional ribbon diagram of the domain of the human U2AF minimal heterodimer. (B) Close-up image of the U2AF³⁵ ΨRRM region proposed to contact RNA. The β-sheet containing the RNP1-like peptide is colored yellow, and the β-sheet containing the RNP2-like peptide is shown in red. Amino acids corresponding to those mutated in the present study are shown as stick figures to allow the orientations of side chains to be visualized. Numbers and identities of the amino acids in the small subunit of S. pombe U2AF are given in parentheses where they differ from the human ortholog. The images were prepared using RasMol software (version 2.7.2.1) (42) and the coordinates supplied by Kielkopf et al. (24).