With no explanation, label each line with "O", "other-biologything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart", "building-airport" or "building-hospital" preceded by ":".
When
tryptophan
is
present
,
these
tryptophan
repressor
dimers
bind
to
tryptophan
,
causing
a
change
in
the
repressor
conformation
,
allowing
the
repressor
to
bind
to
the
operator
.
When:O
tryptophan:other-biologything
is:O
present:O
,:O
these:O
tryptophan:other-biologything
repressor:O
dimers:O
bind:O
to:O
tryptophan:other-biologything
,:O
causing:O
a:O
change:O
in:O
the:O
repressor:O
conformation:O
,:O
allowing:O
the:O
repressor:O
to:O
bind:O
to:O
the:O
operator:O
.:O