Table 1.

NeuAc-binding affinity of the different mutants.

Nanosensorsa	Generated mutants	Kd	Detection rangeb	ΔRmax§
Flip-SA 157	Wild-type protein	157 μM	1.58 μM−1.56 mM	0.25
Flip-SA 13	D49K	13 nM	1.0 nM−49.5 μM	0.32
Flip-SA 510	R127D	510 nM	80 nM−96.7 μM	0.34
Flip-SA 600	E67N	600μM	24 μM−10 mM	0.14

^aThe nanosensor mutant name was based on the K_dvalue.

^bThe quantification range fell between 10 and 90% saturation of the sensors.

^§Maximal change in the FRET ratio of the sensor.