CanlonicSF is a genetically-encoded single-fluorophore nanosensor for lactate. It consists of the TTHA0766 gene from Thermus thermophilus (UniProtKB:Q5SK82), into which a circularly permuted green fluorescent protein (cpGFP) flanked by a two residue linker on each side has been inserted at position 177. In addition, a Y10A mutation has been introduced into the TTHA0766 coding sequence (FBrf0255149).