<p>This entry includes some of the AAA proteins not detected by the <db_xref db="INTERPRO" dbkey="IPR003959"/> model.</p><p>AAA ATPases form a large, functionally diverse protein family belonging to the AAA+ superfamily of ring-shaped P-loop NTPases, which exert their activity through the energy-dependent unfolding of macromolecules. AAA ATPases contain a P-loop NTPase domain, which is the most abundant class of NTP-binding protein fold, and is found throughout all kingdoms of life [<cite idref="PUB00014778"/>]. P-loop NTPase domains act to hydrolyse the beta-gamma phosphate bond of bound nucleoside triphosphate. There are two classes of P-loop domains: the KG (kinase-GTPase) division, and the ASCE division, the latter including the AAA+ group as well as several other ATPases.</p><p>There are at least six major clades of AAA domains (metalloproteases, meiotic proteins, D1 and D2 domains of ATPases with two AAA domains, proteasome subunits, and BSC1), as well as several minor clades, some of which consist of hypothetical proteins [<cite idref="PUB00014779"/>]. The domain organisation of AAA ATPases consists of a non-ATPase N-terminal domain that acts in substrate recognition, followed by one or two AAA domains (D1 and D2), one of which may be degenerate.</p> ATPase, AAA-3