RT Journal Article SR Electronic T1 The SensorOverlord predicts the accuracy of measurements with ratiometric biosensors JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.01.31.928895 DO 10.1101/2020.01.31.928895 A1 Stanley, Julian A. A1 Johnsen, Sean B. A1 Apfeld, Javier YR 2020 UL http://biorxiv.org/content/early/2020/02/01/2020.01.31.928895.abstract AB Two-state ratiometric biosensors change conformation and spectral properties in response to specific biochemical inputs. Much effort over the past two decades has been devoted to engineering biosensors specific for ions, nucleotides, amino acids, and biochemical potentials. The utility of these biosensors is diminished by empirical errors in fluorescence-ratio signal measurement, which reduce the range of input values biosensors can measure accurately. Here, we present a formal framework and a web-based tool, the SensorOverlord, that predicts the input range of two-state ratiometric biosensors given the experimental error in measuring their signal. We demonstrate the utility of this tool by predicting the range of values that can be measured accurately by biosensors that detect pH, NAD+, NADH, NADPH, histidine, and glutathione redox potential. The SensorOverlord enables users to compare the predicted accuracy of biochemical measurements made with different biosensors, and subsequently select biosensors that are best suited for their experimental needs.