Precipitation of coatomer with synthetic peptides
corresponding to the COOH termini of p23wt, p23AS and Wbp1p.
(A) Peptides used in this study. p23wt represents the
cytoplasmic domain of p23, which binds coatomer depending on its
dilysine and diphenylalanine motifs, whereas p23AS lacks these residues
and therefore does not bind coatomer. Wbp1p represents the cytoplasmic
domain of a subunit of the yeast N-oligosaccharyl
transferase complex bearing a characteristic KKXX ER-retrieval motif
known to bind coatomer. (B and C)
Precipitation of coatomer (0.09 μM) with monomeric (B) and
dimeric (C) peptides. Only p23wt (■) precipitates
the complex, whereas mutated p23 peptide (p23AS, ●) and
Wbp1p (▴) have no effect. The error bars indicate standard
errors (n = 3).