Figure 1.

A glucose sensor with enhanced signal change due to linker truncations. (A) FLIPglu construct consisting of N-terminal His-tag, ECFP (cyan), an N-terminal composite linker (CL-N), the mature MglB (red), a C-terminal composite linker (CL-C), and EYFP (yellow). (B) Emission spectra of FLIPglu-600μΔ13 in the presence and the absence of 10 mM glucose (excitation 433 nm). (C) Glucose binding isotherms of FLIPglu-600μ and FLIPglu-600μΔ13. (D) Correlation of Δratio and the number of amino acids deleted from the composite linkers. After deletion of >20 amino acids from the two composite linkers, increased FRET changes are observed.