FIGURE 6.

Peptide coverage of identified 20 S proteasomal Htt cleavage products. Purified Htt-exon1-25/97Q-H4 proteins were incubated with purified mammalian 20 S proteasomes for 16 h at 37 °C. Fractionation of the <3-kDa peptide pool with a flow-through 3-kDa microconcentrator was performed, and separated Htt peptides generated by the 20 S proteasome were used for subsequent mass spectrometry analysis. Htt-exon1-25/97Q-H4 sequences of peptides identified as proteasome-mediated degradation products are shown in green (N-terminal) and red (C-terminal).