Structural Basis of Chaperone Function and Pilus Biogenesis

• DOI: 10.1126/science.285.5430.1058
• Publication Date: 2002-07-27T09:42:20Z
• Authors: Frederic G. Sauer; Klaus Fütterer; Jerome S. Pinkner; Karen W. Dodson; Scott J. Hultgren; Gabriel Waksman
• Keywords: Models, Molecular; Protein Folding; 0303 health sciences; Protein Conformation; Escherichia coli Proteins; Molecular Sequence Data; Crystallography, X-Ray; Protein Structure, Secondary; 3. Good health; 03 medical and health sciences; Bacterial Proteins; Fimbriae, Bacterial; Escherichia coli; Amino Acid Sequence; Fimbriae Proteins; Periplasmic Proteins; Sequence Alignment; Molecular Chaperones

Many Gram-negative pathogens assemble architecturally and functionally diverse adhesive pili on their surfaces by the chaperone-usher pathway. Immunoglobulin-like periplasmic chaperones escort pilus subunits to the usher, a large protein complex that facilitates the translocation and assembly of subunits across the outer membrane. The crystal structure of the PapD-PapK chaperone-subunit complex, determined at 2.4 angstrom resolution, reveals that the chaperone functions by donating its G 1 β strand to complete the immunoglobulin-like fold of the subunit via a mechanism termed donor strand complementation. The structure of the PapD-PapK complex also suggests that during pilus biogenesis, every subunit completes the immunoglobulin-like fold of its neighboring subunit via a mechanism termed donor strand exchange.