Figure 4 - full size

 

Figure 4.
Fig. 4. Comparison of the RNA-interacting regions of Tap with those found in the U2B''-U2A'-RNA complex. (A) The Tap protein (96-372) is shown as a yellow ribbon rendering. The 1- and 3-strands of the RNP fold are shown as magenta arrows for comparison with the spliceosomal complex shown in B. Residues in the RNP and LRR domains of Tap that are critical for CTE binding (R128, K129, K132, R233, R249, R276, Y278, and K304) are shown as red balls and sticks. (B) A ribbon rendering of the structurally analogous spliceosomal complex including an RNP domain (U2B'') in yellow and LRR domain (U2A') in orange and a blue stick model of the hairpin fragment of U2 RNA as reported in the crystal structure (PDB ID code 1A9N) is shown. The same strands, 1 and 3, which include the residues of the RNP motifs (RNP2 and RNP1), are shown in magenta for comparison with Tap. The RNA-interacting surfaces of U2B'' and U2A' are clearly distinct from the CTE-interacting surfaces in Tap identified in our mutational analysis.