With no explanation, label each line with "O", "other-chemicalthing", "other-biologything", "art-broadcastprogram", "art-film", "art-music", "art-other", "art-painting", "art-writtenart" or "building-airport" preceded by ":".
One
of
the
principal
differences
between
HTH
motifs
in
these
different
proteins
arises
from
the
stereochemical
requirement
for
glycine
in
the
turn
which
is
needed
to
avoid
steric
interference
of
the
beta-carbon
with
the
main
chain
:
for
cro
and
repressor
proteins
the
glycine
appears
to
be
mandatory
,
whereas
for
many
of
the
homeotic
and
other
DNA
-binding
proteins
the
requirement
is
relaxed
.
One:O
of:O
the:O
principal:O
differences:O
between:O
HTH:other-biologything
motifs:O
in:O
these:O
different:O
proteins:O
arises:O
from:O
the:O
stereochemical:O
requirement:O
for:O
glycine:other-chemicalthing
in:O
the:O
turn:O
which:O
is:O
needed:O
to:O
avoid:O
steric:O
interference:O
of:O
the:O
beta-carbon:O
with:O
the:O
main:O
chain:O
::O
for:O
cro:other-biologything
and:O
repressor:other-biologything
proteins:other-biologything
the:O
glycine:other-chemicalthing
appears:O
to:O
be:O
mandatory:O
,:O
whereas:O
for:O
many:O
of:O
the:O
homeotic:O
and:O
other:O
DNA:other-biologything
-binding:O
proteins:O
the:O
requirement:O
is:O
relaxed:O
.:O