Figure 3.

(A) The Kyte-Doolittle hydropathy plot for PS-1 (1) by using a window of 15 residues. The roman numerals indicate the hydrophobic sequences serving as TM spanning stretches in B (see text). (B) The topographies of the three proposed models of PS proteins, the 6- (magenta), 7- (red), and 8- (blue) TM spanning models. The correspondingly colored arrows indicate the polypeptide chain directions starting from the NH₂ terminus (NH₂) toward the COOH terminus (COOH) for each model. The long black arrow indicates the region of the proposed endoproteolytic cleavage of the PS proteins (see text).