PROSITE documentation PDOC51772
Actin cross-linking (ACD) domain profile


Actin cross-linking domains (ACDs) are distinct domains found in several bacterial toxins, including the Vibrio cholerae MARTX toxin. ACDs are enzyme ligases that catalyze the formation of an irreversible iso-peptide bond on two actin molecules in an ATP- and Mg/Mn(2+)-dependent manner. Cross-linking depletes the cellular pool of G-actin leading to actin cytoskeleton depolymerization [1,2].

The ACD has an overall V-shape. with the active site composed of five residues in a cleft located within the two arms of the V (see <PDB:4DTD>). The first subdomain, forming the left arm of the V, is mainly composed of β-strands, while the second subdomain, forming the right arm of the V, is helical. The first subdomain is composed of a central anti-parallel β-sheet of 8 β-strands, decorated by two adjacent small β-sheets, one above the central β-sheet and the second below. A long helix (α1) packs against strands β7-β4-β5 from the central β-sheet, and strand β8 from the upper β-sheet. Finally, the terminal helix α9 packs against strands β2 and β9. The second subdomain is composed of 7 α-helices (α2-α8) and does not contain any β-strands [2].

The profile we developed covers the entire ACD domain.

Last update:

August 2015 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

ACD, PS51772; Actin cross-linking (ACD) domain profile  (MATRIX)


1AuthorsGeissler B. Bonebrake A. Sheahan K.-L. Walker M.E. Satchell K.J.F.
TitleGenetic determination of essential residues of the Vibrio cholerae actin cross-linking domain reveals functional similarity with glutamine synthetases.
SourceMol. Microbiol. 73:858-868(2009).
PubMed ID19656298

2AuthorsDurand E. Derrez E. Audoly G. Spinelli S. Ortiz-Lombardia M. Raoult D. Cascales E. Cambillau C.
TitleCrystal structure of the VgrG1 actin cross-linking domain of the Vibrio cholerae type VI secretion system.
SourceJ. Biol. Chem. 287:38190-38199(2012).
PubMed ID22898822

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