FIG. 5.

CUS2 is structurally homologous to Tat-SF1. (A) Schematic comparison of CUS2 and Tat-SF1. Tat-SF1 is more than twice as large as CUS2, but most of this difference resides in the C-terminal acidic domain that is greatly shortened in CUS2. The unfilled regions share a charged nature but little sequence identity. (B) “Stitched” BLAST results generated by comparison of CUS2 with UAP2 and the first 420 residues of Tat-SF1. Each RRM is designated between angle brackets with RNP-1 and RNP-2 within each RRM indicated. Identical and similar amino acids are boxed in black and gray, respectively. The positions of the Y48D mutation, the C-terminal truncation (I∗), and CUS2-9 (L284F) and CUS2-25 (D282N) suppressor substitutions are shown.