FIGURE 1.

CB1 C-tail peptide sequence and purification analysis. (A) Schematic representation of the sequence of the human CB1 C-tail peptide. The CB1 C-tail peptide sequence is given in the box. The five residues on the left are derived from the cloning vector after PreScission protease cleavage to remove GST, and the eight residues to the right of the box are two lysines and a His-tag as described in Materials and Methods. The amino acid numbers corresponding to the location in the sequence of the full-length wild-type human CB1 receptor are indicated. Note several studies of helix 8 employ the rat sequence that has an additional residue in the region.¹²,¹³,³⁰–³² (B) Tris-tricine SDS-PAGE analysis of the CB1 C-tail peptide expression and purification products. Lane 1: crude lysate; Lanes 2 and 3: on-column protease cleavage of the GST-fusion for 4 h and overnight, respectively; Lane 4: resin only after peptide elution to analyze for incomplete peptide removal; Lanes 5 and 6: C-tail peptide eluted after 4 h and overnight cleavage, respectively. (C) Western blot of the C-tail peptide after SDS-PAGE. Lane 1: crude lysate probed with antiserum against the His-tag; Lanes 2 and 3: peptide samples eluted after 4 h and overnight cleavage, respectively, and probed with antiserum against the His-tag; Lanes 4 and 5: peptide samples eluted after 4 h and overnight cleavage, respectively, probed with an antibody against the CB1 C-tail.