Tracking mutation and drug-driven alterations of oncokinase conformations.

Numerous kinases act as central nodes of cellular signaling networks. As such, many of these enzymes function as molecular switches for coordinating spatiotemporal signal transmission. Typically, it is the compartmentalized phosphorylation of protein substrates which relays the transient input signal to determine decisive physiological cell responses. Genomic alterations affect kinase abundance and/or their activities which contribute to the malignant transformation, progression, and metastasis of human cancers. Thus, major drug discovery efforts have been made to identify lead molecules targeting clinically relevant oncokinases. The concept of personalized medicine aims to apply the therapeutic agent with the highest efficacy towards a patient-specific mutation. Here, we discuss the implementation of a cell-based reporter system which may foster the decision-making process to identify the most promising lead-molecules. We present a modular kinase conformation (KinCon) biosensor platform for live-cell analyses of kinase activity states. This biosensor facilitates the recording of kinase activity conformations of the wild-type and the respective mutated kinase upon lead molecule exposure. We reflect proof-of-principle studies demonstrating how this technology has been extended to profile drug properties of the full-length kinases BRAF and MEK1 in intact cells. Further, we pinpoint how this technology may open new avenues for systematic and patient-tailored drug discovery efforts. Overall, this precision-medicineoriented biosensor concept aims to determine kinase inhibitor specificity and anticipate their drug efficacies.

Quantification of melamine in infant formula using a handheld Raman spectrometer - Performance boost with customized Arduino-controlled rotation setup.

This study investigated the performance of a handheld Raman spectrometer in quantifying melamine in infant formula. Furthermore, the spectrometer's standard stationary sample holder was compared to a custom-built sample rotation unit. The Raman spectra were divided into a calibration set, which was used to construct the partial least squares regression (PLS-R) models, and a test set, which served the purpose of evaluating the model performance with independent samples. It was found that it was possible to reduce the prediction error of melamine in infant formula by up to about 70% using the simple in-house constructed rotation setup. Compared to the rotation setup, even an increased number of point measurements using the spectrometer's standard sample holder was not able to compensate for the lack of representative sample presentation of the inhomogeneous solid mixture to the Raman spectrometer. Moreover, it was found that the custom-built rotation unit enabled faster sample measurements by an adaption of spectrometer parameters. At the same time, the prediction error of the test set samples was kept far lower than with the stationary setup.