The most important region to stabilize the structure of ZF2 comprises residues 151-153 in TTP (residues 201-203 in TIS11d). (Left) Overlay of the15N-1H HSQC spectrum of WT TIS11d (blue) with that of the mutant protein containing the TTP amino acid sequence at the second half of the α-helical region of ZF2, residues 201-203, (black). (Right) Overlay of the 15N-1H HSQC spectrum of WT TTP (red) with that of the mutant protein containing the TIS11d amino acid sequence at the α-helical region of ZF2, residues 148-155, (black). On top, a schematic representation of the TZF domain shows the zinc fingers as rectangles and the linker as line. The dots indicate residues along the sequence with a cross-peak in the 15N-1H HSQC spectrum.