1sr4 | pdb_00001sr4
Crystal Structure of the Haemophilus ducreyi cytolethal distending toxin
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| 1sr4, resolution 2.0Å | |||||||||||||
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| Ligands: | BR | ||||||||||||
| Gene: | CDTA, HD0902 (Haemophilus ducreyi) | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Overview
The tripartite cytolethal distending toxin (CDT) induces cell cycle arrest and apoptosis in eukaryotic cells. The subunits CdtA and CdtC associate with the nuclease CdtB to form a holotoxin that translocates CdtB into the host cell, where it acts as a genotoxin by creating DNA lesions. Here we show that the crystal structure of the holotoxin from Haemophilus ducreyi reveals that CDT consists of an enzyme of the DNase-I family, bound to two ricin-like lectin domains. CdtA, CdtB and CdtC form a ternary complex with three interdependent molecular interfaces, characterized by globular, as well as extensive non-globular, interactions. The lectin subunits form a deeply grooved, highly aromatic surface that we show to be critical for toxicity. The holotoxin possesses a steric block of the CdtB active site by means of a non-globular extension of the CdtC subunit, and we identify putative DNA binding residues in CdtB that are essential for toxin activity.
About this Structure
1SR4 is a Protein complex structure of sequences from Haemophilus ducreyi. Full crystallographic information is available from OCA.
Reference
Assembly and function of a bacterial genotoxin., Nesic D, Hsu Y, Stebbins CE, Nature. 2004 May 27;429(6990):429-33. PMID:15164065
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