Clickable Sequence to 3D in Protein Explorer
The one-letter chain sequences at the lower right are interactive in Protein Explorer (but not in this snapshot). Touching a residue shows the three-letter amino acid code. Clicking on a residue, or range, displays them in the 3D structure according to the menu choices selected at the top left.

In the image here, the sequence SPKTKRSPLT has been highlighted in ball-and-stick.
(The links in the snapshot don't work since this is just a snapshot.)