Fig. 6. Partitioning of chaperone action.
A, Predicted Hsp70 binding sites (side chains of leucine, isoleucine, valine, phenylalanine and tyrosine shown as yellow spheres) form the nucleus of folding intermediates (four examples, Dihydrolipoyllysine-residue acetyltransferase (1W4G), Pre-mRNA-processing factor 40 homolog A (2KZG), Thermonuclease (2KQ3) and Flavodoxin (2KQU)), leaving scattered hydrophobic residues in the periphery (LIVFYW residues; red spheres). (B) The Tau ensemble, color coded as in (A). The repeat regions are indicated as in Figure 1E. C, Model for partitioning of chaperone action between the Hsp70 and Hsp90 systems. Hsp70 binds early when its binding sites are accessible. During folding, the Hsp70 binding sites disappear, leaving scattered hydrophobics that are recognised by Hsp90. The folded protein will bury also those residues. See also Fig. S4.