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PRIMARY EFFECT. “Here, we have studied the taste of D2O and H2O per se, not related to washing away of sweet taste inhibitors. Using psychophysics protocols, we show that humans differentiate between D2O and H2O based on taste alone. Importantly, by employing gas chromatography/mass spectrometry analysis we demonstrate that the sweet taste of deuterated water is not due to impurities.” https://lnkd.in/dzPDm5w View in LinkedIn

SWEET TASTE INHIBITORS. “Sweet taste never ceases to surprise. Over a decade ago, water was shown to elicit sweet taste by rinsing away inhibitors of sweet taste receptors, both in human sensory experiments and in cell-based studies. This effect was explained in terms of a two-state model, where the receptor shifts to its activated state when released from inhibition by rinsing with water.” https://lnkd.in/dzPDm5w View in LinkedIn

AQUEOUS MILIEU. “Structural fluctuations of most residues (particularly those directly exposed to the aqueous environment) and of the protein as a whole are slightly attenuated in D2O, in which environment the protein is also somewhat more compact than in H2O (Fig. 7b). Additional simulations on other representative systems show that the rigidifying effect of heavy water is apparent also in small soluble proteins.” https://lnkd.in/dzPDm5w View in LinkedIn

BINDING CONFIGURATION. “Figure 7b shows the time evolution of the radius of gyration of the TMD domain, while Fig. 7c and d presents the root mean square fluctuations (RMSF) of individual residues of the proteins superimposed on its structure and plotted in a graph together with the mean value of RMSF. A small but significant difference is apparent in the behavior of the protein in H2O vs D2O.” https://lnkd.in/dzPDm5w View in LinkedIn

RECEPTOR BINDING. “H2O and D2O have mutually slightly shifted densities inside the protein cavity, with H2O overlapping better than D2O with the modeled water positions. Furthermore, MD simulations show clustered water molecules close to the lactisole binding site. These internal positions may have a differential effect between H2O and D2O, though differences between the averaged water densities are not very pronounced.” https://lnkd.in/dzPDm5w View in LinkedIn

This extraordinary book was written by a man who I have been close friends with since we were 9 years old. Even then, he wanted to be an entomologist. He has been living his dream for his entire life. View in LinkedIn

SO ENDS this second and last weekend on a paper showing that heavy water tastes different from normal water. Not only was the finding surprising, but the studies were exceptionally thorough, confirming the result at the taste receptor level. This study is an exemplar of good experimental science, with an initial hypothesis, preliminary findings, testing those findings in alternative systems, and finally nailing the conclusions by these confirmations. View in LinkedIn

APPLICATIONS. “While clearly not a practical sweetener, heavy water provides a glimpse into the wide-open chemical space of sweet molecules. Since heavy water may be used in medical procedures, our finding that it can elicit responses of the sweet taste receptor, which is not only located on the tongue but also in other tissues of the human body, represents an important information for clinicians and their patients. Moreover, due to wide application of D2O in chemical structure determination by NMR, chemists will benefit from being aware of the present observations.” https://lnkd.in/dzPDm5w View in LinkedIn

TASTING ISOTOPES. “The finding that deuterated water elicits sweet taste via activation of TAS1R/TAS1R2 receptor is of fundamental interest. The difference between hydrogen isotopes is the largest possible isotope effect (doubling of mass in case of deuterium, while tripling in case of tritium), yet deuteration effects on water are generally mild. Nevertheless, water deuteration leads to activation of a GPCR heterodimer to a level that is perceived by humans as sweet taste.” https://lnkd.in/dzPDm5w View in LinkedIn

DIGITAL LOGIC GATES. “We created soft, mechanical metamaterials with flexible, conductive polymer networks that can compute all digital logic computations.” https://lnkd.in/dFqRRmn View in LinkedIn