EXPRESSION IN ESCHERICHIA-COLI AND CHARACTERIZATION OF THE HUMAN CENTRAL CB1 AND PERIPHERAL CB2 CANNABINOID RECEPTORS

The human central CB1 and peripheral CB2 cannabinoid receptors were ex pressed in Escherichia coli as fusion proteins with the maltose-bindin g protein at their amino-termini and a hexa-histidine/Flag tag at thei r carboxyl-termini. Western blot analysis of the expressed proteins re vealed considerable degradation of the CB1 fusion, which failed to bin d either the cannabinoid agonist CP 55,940 or the CB1-specific antagon ist SR 141716A. In contrast, the CB2 fusion was well-expressed and bou nd several cannabinoids with affinities comparable to those observed i n mammalian expression systems.