Abstract: The invention relates to a protein, which comprises an adenylate cyclase domain in addition to an ion channel domain. The ion channel domain is preferably a potassium ion channel domain, which is sensitive to voltage. In addition, the protein has a C-terminal protein-protein interaction domain. The invention also relates to nucleotide sequences, which code for proteins of this type.

Abstract: A method for expression of membrane proteins is provided, wherein at least a portion of a nucleotide sequence coding to the membrane protein is fused to at least a portion of a nucleotide sequence coding for an adenylyl cyclase of Mycobacterium tuberculosis or a sequence at least about 70% identical to said sequence of Mycobacterium tuberculosis. In a second step the fused nucleotide sequence is introduced into an organism and/or a living cell. Another aspect of the invention is a method for searching active agents, which interact directly with adenylyl cyclases.