Fig. 5.

Allosteric changes around the catalytic site of PS1 induced by ST1120. (A) Positions of the mutated residues in the homology model of PS1, based on the crystal structure of archaea PSH. Catalytic aspartates are shown as red spheres in TM6 and TM7. (B) Competition assay in SCAM-based biotinylation of the PS1 L381C and L383C mutants by ST1120. (C) Effects of ST1120 on the cross-linking of double-cysteine mutants of PS1. We used 1,2-ethanedithiol dimethanesulphonate that harbors a 5.0-Å spacer as a cross-linking reagent. Note that the levels of cross-linked products and fragments of L250C/L435C were specifically decreased and increased, respectively, by ST1120.