Full Sequence Display in Protein Explorer
Touching the one-letter amino acid codes displays the three-letter amino acid abbreviation in the center white slot (but not in this snapshot). The checkboxes can be used to color selected amino acids for easy spotting.

Gaps and insertions in chain B are easy to spot in this display. Clicking the link "More Information" displays the white window at lower right.
(The links in the snapshot don't work since this is just a snapshot.)