Fig. 5.

Combined structure of the TAR-peptide complex and the TAR loop-SEC complex. The TAR-peptide complex (PDB ID 2KX5; TAR: slate; peptide: magenta) and the TAR loop-SEC complex (coloring as in Fig. 2) are aligned on the common TAR component. Tat and CycT1 TRM contact the TAR loop. The TAR bulge is positioned in a pocket formed by CycT1 helices H1, H3, and H4 and Tat residue G48, adjacent to the missing Tat ARM, whose binding site is indicated by the Tat-peptide mimetic bound in the major groove of TAR. Views A and B are rotated 180°.