Effect of alcohols on a soluble form of adenylyl cyclase type 7 expressed in bacteria

Abstract

Cyclic AMP (cAMP) signal transduction has been postulated to play an important role in the development of alcoholism in humans. Our previous studies showed that generation of cAMP by mammalian membrane‐bound adenylyl cyclase (AC) is enhanced in an isoform specific manner and that alcohol‐cutoff phenomena are also isoform‐specific. We hypothesized that alcohols exhibit their effect on AC activity by direct interaction with AC proteins. However, experimental systems employed in the past such as intact cells and membrane preparations are too complex and do not allow us to unequivocally test this hypothesis. We decided to study the effect of alcohols on AC recombinant proteins expressed in bacteria. A type 7 AC (AC7) recombinant protein consisting of the C1a and C2 domains was designed and expressed in E. coli. The AC activity of the soluble form of AC7 recombinant protein was significantly increased by manganese and forskolin. In addition, n‐alkanols (ethanol to hexanol) significantly enhanced manganese‐stimulated activity of the AC7 recombinant protein. The alcohol cutoff for this recombinant protein is pentanol, which is same as that of wild type observed in mammalian system. These results suggest that the AC7 recombinant protein retains alcohol response similar to that of the parent enzyme. The results are consistent with our working hypothesis. Supported by NIH Grant AA13148 (MY).