GlucoSnFR is a genetically encoded fluorescent sensor designed for in vivo detection of glucose. It is a fusion protein composed of the glucose binding protein (GBP) from Thermus thermophilus (lacking the periplasmic secretion leader peptide encoded by amino acids 1-26), with a permuted form of GFP inserted (with linkers either side) between residues 326 and 327. Amino acid replacements H66A, L276V and H348A have been introduced into the GBP sequence to decrease glucose affinity (FBrf0249411).