<p>PAC motifs occur C-terminal to a subset of all known PAS motifs (see <db_xref db="INTERPRO" dbkey="IPR000014"/>). It is proposed to contribute to the PAS domain fold [<cite idref="PUB00005472"/>, <cite idref="PUB00000420"/>, <cite idref="PUB00006196"/>].</p> PAC motif