Pay special attention to the suspicious location of the purple Trp-90.
The 'active site' of all α/β proteins with parallel β-sheets
is always at or near the C-terminal ends of the β-strands. But the thing
that gives the answer away is the Gly-Trp-Gly with the hyper-exposed Trp.
That is not normal, and the active site is always the spot where something is
not normal.
If the students don't get it, put the molecule up on the central screen with
the Trp-90 (and its both flanking Gly-s) well visible as sticking out:
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Pay special attention to the suspicious location of the purple Trp-90. |