G-Flamp1 is a genetically encoded fluorescent cAMP sensor. It consists of an N-terminal RSET leader sequence (which includes Tag:polyHis), followed by the cyclic nucleotide-binding domain (residues 213-355) of the Mesorhizobium loti K1 potassium channel into which a circularly permuted green fluorescent protein (cpGFP) flanked by a two residue linker on each side has been inserted (between residues 285 and 286). A number of mutations have been introduced into the fusion protein relative to the starting template. For detailed kinetic and spectral properties of G-Flamp1, and a comparison with other fluorescent cAMP sensors, see PMID:36097007.