Structure and biogenesis of the capsular F1 antigen from Yersinia pestis: Preserved folding energy drives fiber formation

: Zavialov AV, Berglund J, Pudney AF, Fooks LJ, Ibrahim TM, MacIntyre S, Knight SD

Publisher: CELL PRESS

: 2003

: Cell

: CELL

: 113

: 5

: 587

: 596

: 10

: 0092-8674

DOI: https://doi.org/10.1016/S0092-8674(03)00351-9

Most gram-negative pathogens express fibrous adhesive virulence organelles that mediate targeting to the sites of infection. The F1 capsular antigen from the plague pathogen Yersinia pestis consists of linear fibers of a single subunit (Caf1) and serves as a prototype for nonpilus organelles assembled via the chaperone/usher pathway. Genetic data together with high-resolution X-ray structures corresponding to snapshots of the assembly process reveal the structural basis of fiber formation. Comparison of chaperone bound Caf1 subunit with the subunit in the fiber reveals a novel type of conformational change involving the entire hydrophobic core of the protein. The observed conformational change suggests that the chaperone traps a high-energy folding intermediate of Caf1. A model is proposed in which release of the subunit allows folding to be completed, driving fiber formation.