Structure of the Yersinia enterocolitica molecular-chaperone protein SycE

The crystal structure of the Yersinia enterocolitica molecular-chaperone protein SycE, which specifically binds the YopE protein, has been solved to 2.0 A resolution by molecular replacement. The crystal contains two SycE dimers per asymmetric unit; a novel feature of this crystal, when compared with closely related SycE structures, is a well ordered carboxy-terminal peptide in one protomer of each dimer. The peptide binds a hydrophobic patch of a neighboring molecule in a manner similar to that seen in a SycE-YopE chaperone-target complex, suggestive of low-affinity 'self-binding' through which the carboxy-terminal peptide might suppress counterproductive interactions with non-target proteins in vivo.