Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2008 Apr 30;9(4):216.
doi: 10.1186/gb-2008-9-4-216.

The AAA+ superfamily of functionally diverse proteins

Jamie Snider  1 , Guillaume Thibault, Walid A Houry
Affiliations
Review

The AAA+ superfamily of functionally diverse proteins

Jamie Snider et al. Genome Biol. .

Abstract

The AAA+ superfamily is a large and functionally diverse superfamily of NTPases that are characterized by a conserved nucleotide-binding and catalytic module, the AAA+ module. Members are involved in an astonishing range of different cellular processes, attaining this functional diversity through additions of structural motifs and modifications to the core AAA+ module.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Structure of the AAA+ module. (a) Monomeric AAA+ module of Aquifex aeolicus DnaA, a protein involved in the initiation of DNA replication (Protein Data Bank (PDB) code 2HCB) [5]. The α-helices and random coils are in green and the β-strands of the core αβα nucleotide-binding domain are in blue, with the exception of the two equal-sized helical inserts, which are colored pink. The small α-helical domain is colored purple. (b) Major motifs in the AAA+ module of (a) are colored as indicated in the key, on the basis of the alignment in reference [3]. The bound adenosine 5'-[β,γ-methylene]triphosphate (β,γ-methylene-ATP, a nonhydrolyzable ATP analog, orange sticks) and Mg2+ (black sphere) are also shown. (c) Top and side views of the hexameric structure of Haemophilus influenzae HslU, a member of the HslU/ClpX family (PDB 1KYI) [64]. α-Helices, including random coils, and β-strands of the core αβα nucleotide-binding domain are colored green and blue, respectively. Two additional helices characteristic of HslU-family proteins, called the I domain, are colored orange, and an additional extended loop between the second core β-strand and the following helix is colored in pink. The core small α-helical domain is colored purple, with the two-stranded β-sheet insertion in yellow. Structures were drawn using PyMOL [65].
Figure 2
Figure 2
Structures of the AAA+ modules of selected superfamilymembers (see Table 1). The core αβα nucleotide-binding domains are shown in green (α-helices and random coil) and blue (β-strands). The small, α-helical domain of each AAA+ module is shown in purple. The canonical AAA+ module structure is exemplified by that of RFC1, which is shown in the center. (a) Representative members of the extended AAA group [6]. The FtsH AAA+ module from Thermus thermophilus (left, PDB 2DHR) contains an additional small helix (pink) downstream of the second β-strand, which is characteristic of the classical AAA clade [1,15]. The function of FtsH is discussed in the text. The Rvb AAA+ module, represented by human Rvb1 (center, PDB 2C90), contains a β-sheet-rich insert (pink) upstream of the Walker B motif and an additional small helix (yellow) downstream of the second β-strand of the core domain [1]. The β-sheet-rich insert is proposed to play a role in sequence-independent DNA and RNA binding [66]. The amino-terminal (D1) AAA+ modules of ClpB-type proteins are represented by a structure from T. thermophilus (right, PDB 1QVR). These proteins contain a long, leucine-rich coiled-coil propeller domain (pink) inserted into the small α-helical domain [67]. This propeller domain is proposed to play a role in interdomain communication and protein disaggregation, possibly acting as a molecular crowbar [67]. (b) Representative members of the HEC group [6]. The RFC1 AAA+ module from S. cerevisiae (center, PDB 1SXJ) represents a 'classical' AAA+ module containing no structural modifications and typifies the clamp loader clade to which it belongs [1,68]. The DnaA AAA+ module from Aquifex aeolicus (left, PDB 2HCB2HCB) contains an insert of two equal-sized helices (pink) after the second β-strand and is representative of the initiation clade [9]. The RuvB AAA+ module from T. thermophilus (right, PDB 1HQC) contains a β-hairpin insert (pink) between sensor 1 and its preceding helix [35]. This insert is characteristic of the RuvB family and is known to be important for the interaction of RuvB with RuvA in the resolution of Holliday junctions in DNA recombination [69,70]. The function of RuvB is discussed in the text. (c) Representatives of the PACTT group. Members of this group all contain a β-hairpin insert (cyan, shown in all three structures) between the sensor 1 strand and the preceding helix [1]. The BchI AAA+ module from Rhodobacter capsulatus Mg2+ chelatase (left, PDB 1G8P) belongs to the helix-2 insert clade. Members of this clade contain a small insert of two β-strands flanking a small α-helix (pink) in helix 2 of the αβα core domain and a long helical insert (yellow) between the fifth β-strand of the core domain and the small α-helical domain [1,24]. BchI proteins also contain a long, highly conserved β-hairpin insert (orange) upstream of the second β-strand of the core domain [24]. The function of BchI is discussed in the text. The carboxy-terminal ClpA AAA+ module (D2) from Escherichia coli (center, PDB 1KSF) [71] and the HslU AAA+ module from E. coli (right, PDB 1G4A) [72] are both representative members of the HCL clade, whose members are involved in protein unfolding and degradation. These structures contain an extended loop (pink) between the second core β-strand and the following helix [1] and a two or three stranded β-sheet insert (yellow) in the small α-helical domain of the AAA+ module, both characteristic of this clade. In addition, HslU family members contain an additional 130 amino acid I domain (orange, only part of the domain is resolved in the crystal structure) inserted into the core αβα domain of the AAA+ module, which is proposed to play a role in substrate recognition and unfolding [73].
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Iyer LM, Leipe DD, Koonin EV, Aravind L. Evolutionary history and higher order classification of AAA+ ATPases. J Struct Biol. 2004;146:11–31. doi: 10.1016/j.jsb.2003.10.010. - DOI - PubMed
    1. Walker JE, Saraste M, Runswick MJ, Gay NJ. Distantly related sequences in the alpha- and beta-subunits of ATP synthase, myosin, kinases and other ATP-requiring enzymes and a common nucleotide binding fold. EMBO J. 1982;1:945–951. - PMC - PubMed
    1. Neuwald AF, Aravind L, Spouge JL, Koonin EV. A class of chaperone-like ATPases associated with the assembly, operation, and disassembly of protein complexes. Genome Res. 1999;9:27–43. - PubMed
    1. Ogura T, Wilkinson AJ. AAA+ superfamily ATPases: common structure - diverse function. Genes Cells. 2001;6:575–597. doi: 10.1046/j.1365-2443.2001.00447.x. - DOI - PubMed
    1. Erzberger JP, Berger JM. Evolutionary relationships and structural mechanisms of AAA+ proteins. Annu Rev Biophys Biomol Struct. 2006;35:93–114. doi: 10.1146/annurev.biophys.35.040405.101933. - DOI - PubMed

Publication types

Substances

LinkOut - more resources