Crystal structure of invasin: A bacterial integrin-binding protein

The Yersinia pseudotuberculosis invasin protein promotes bacterial entry by binding to host cell integrins with higher affinity than natural substrate s such as fibronectin, The 2.3 angstrom crystal structure of the invasin ex tracellular region reveals five domains that form a 180 angstrom rod with s tructural similarities to tandem fibronectin type III domains. The integrin -binding surfaces of invasin and fibronectin include similarly Located key residues, but in the context of different folds and surface shapes. The str uctures of invasin and fibronectin provide an example of convergent evoluti on, in which invasin presents an optimized surface for integrin binding, in comparison with host substrates.