FIGURE 7.

Molecular model for the binding of α-Syn to Ssa1p. The proposed model is based on the identification of the residues involved in the interaction between the heat shock protein Ssa1p and α-Syn, probed by chemical cross-linking. Lys-10, Lys-21, Lys-23, and Lys-97 from α-Syn are exclusively cross-linked to Lys-448, Lys-528, and Lys-556 from Ssa1p, whereas Lys-12 from α-Syn is found cross-linked with Lys-446, Lys-494, Lys-504, or Lys-536 from Ssa1p. This suggest that after the docking of the regions centered on residues Lys-97 and Lys-556 in α-Syn and Ssa1p, respectively, the N-terminal part of α-Syn establishes interactions with either the back or the bottom tip of the client proteins binding site of Ssa1p. At one stage, Ssa1p appears to bind α-Syn as a tweezer, through the two tips of its client protein binding site.