Download MendeleyAssembly and Function of a Bacterial Genotoxin
Nesic, D., Hsu, Y., Stebbins, C.E.(2004) Nature 429: 429-433
- PubMed: 15164065
- DOI: https://doi.org/10.1038/nature02532
- Primary Citation of Related Structures:
1SR4 - PubMed Abstract:
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.
Organizational Affiliation:
Laboratory of Structural Microbiology, The Rockefeller University, New York 10021, USA.
