Figure 1
The crystal structure of the Escherichia coli EscJ protein, a molecular platform for type III secretion, solved using crystals with SER surface engineering (PDB entry 1yj7
; Yip et al., 2005). (a) The content of the asymmetric unit, an EscJ tetramer (each subunit is coloured differently), with the location of the three mutations in the solvent-exposed loop (E62A,K63A,E64A) indicated by arrows; the three alanines introduced by mutagenesis are shown as magenta spheres. (b) The assembly of the EscJ proteins into a 24-unit ring superstructure representative of the early stage of assembly of the type II secretion system (Yip et al., 2005). Note that the mutated patches mediate the only crystal contacts, copied by the sixfold screw axis 65, perpendicular to the plane of the diagram. |