Tryptophan ribbon structure

Fig. 3. The ribbon structure of coil-Ser [pdb identifier, lcos (Lovejoy et al, 1993)]. The structure reveals a mixed parallel/antiparallel three-helix bundle, which is influenced by the three core tryptophan side chains, shown in space-filling representation.

Figure 5-35 Stereoscopic drawings illustrating the binding of a dimeric molecule of the Trp repressor protein to a palindromic sequence in DNA. (A) Schematic view showing structures of the aporepressor (partly shaded gray) and the holorepressor with bound tryptophan (unshaded) are superimposed. Cylinders represent the a helices in (B). From Zhang et al.wi (B) MolScript ribbon diagram with a few side chains that interact with the DNA shown. Two tandemly bound dimeric repressor molecules are shown. Two bound molecules of tryptophan are visible in each dimer. The DNA is drawn as a double helix with lines representing the base pairs. From Lawson and Carey.405...

Fig. 7.2 (A) Protein folding. The small Trpcage protein in an unfolded conformation (left) and its stable, folded conformation (right). The protein backbone is shown in a simpMed, green, tube/ribbon representation. A single, tryptophan sidechain is also shown, which forms the core of the folded structure. (B) Folded proteins. Space-filhng views of cytochrome c (an electron carrier in the respiratory chain) and hemoglobin (an oxygen carrier in the blood), along with a water molecule, approximately to scale...

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