Figure 1.

Sequence comparisons of the fragment 124–226 of mammalian PrP (see text for the selection criteria used), with the mouse sequence as a reference. At the top the locations of the regular secondary structures in mouse PrP(121–231) are indicated, and the sequence numbers refer to the residue under the third digit. The bottom line gives a classification of the observed variable sites into six classes A (blue), B (magenta), C (green), D (orange), 1, and 2 (see text). In addition to the 23 sequences listed here, swissprot and genembl provide three sequences (chimpanzee, gibbon, and siamang) that differ from gorilla only by the exchange N171S, two sequences that differ from that of Presbytis francoisi only by the exchanges N159S and I182V (squirrel monkey) and D144E (sooty mangabey), respectively; for all these sites no amino acid substitutions are observed in any other of the mammalian sequences. There are further two mouse sequences with the replacements M134V and T190V, respectively, relative to the mouse sequence listed here, two bovine sequences with the replacements G143S and G143S/M201K, respectively, a goat sequence with I139M, a pig sequence with N143S, and a squirrel monkey sequence with the exchange R164K.