LmNaTx15, a novel scorpion toxin, enhances the activity of Nav channels and induces pain in mice.

Polypeptide toxins are major bioactive components found in venomous animals. Many polypeptide toxins can specifically act on targets, such as ion channels and voltage-gated sodium (Nav) channels, in the nervous, muscle, and cardiovascular systems of the recipient to increase defense and predation efficiency. In this study, a novel polypeptide toxin, LmNaTx15, was isolated from the venom of the scorpion Lychas mucronatus, and its activity was analyzed. LmNaTx15 slowed the fast inactivation of Nav1.2, Nav1.3, Nav1.4, Nav1.5, and Nav1.7 and inhibited the peak current of Nav1.5, but it did not affect Nav1.8. In addition, LmNaTx15 altered the voltage-dependent activation and inactivation of these Nav channel subtypes. Furthermore, like site 3 neurotoxins, LmNaTx15 induced pain in mice. These results show a novel scorpion toxin with a modulatory effect on specific Nav channel subtypes and pain induction in mice. Therefore, LmNaTx15 may be a key bioactive component for scorpion defense and predation. Besides, this study provides a basis for analyzing structure-function relationships of the scorpion toxins affecting Nav channel activity.

A neutral Cu-based MOF for effective quercetin extraction and conversion from natural onion juice.

We report herein a new microporous neutral three-dimensional (3D) metal-organic framework [Cu2(L)(DMF)(H2O)]·guest (1·guest) composed of copper paddle-wheel and flexible tetracarboxylic acid linkers (DMF = N,N-dimethylformamide, H4L = tetrakis[(6-carboxynaphthoxy)methyl]methane). Surprisingly, this MOF with neutral cavities can not only extract pure quercetin (QT) but also convert it into Cu-QT during the desorption process. It has been well characterized by UV-vis, IR, ESI-MS and TEM-EDS studies. Moreover, it can efficiently extract natural product QT from fresh QT-rich onion juice and rapidly convert it into Cu-QT with a relatively high conversion rate.

Phosphine-Catalyzed Difunctionalization of ß-Fluoroalkyl α,ß-Enones: A Direct Approach to ß-Amino α-Diazo Carbonyl Compounds.

An efficient and practical phosphine-catalyzed vicinal difunctionalization of ß-fluoroalkyl α,ß-enones with TMSN3 has been developed. Using dppb as the catalyst, the reaction worked efficiently to yield various ß-amino α-diazocarbonyl compounds in high yields (up to 94 %). This work marks the first efficient construction of α-diazocarbonyl compounds by phosphine catalysis. Meanwhile, the asymmetric variant induced by the nucleophilic bifunctional phosphine P4 led to various chiral fluoroalkylated ß-amino α-diazocarbonyl compounds in high yields and enantioselectivity. NMR and ESI-MS studies support the existence of the key reaction intermediates. In contrast, ß-azide carbonyl compounds would be furnished in good yields from ß-fluoroalkylated ß,ß-disubstituted enones.