Screening Glycolipids Against Proteins in Vitro Using Picodiscs and Catch-and-Release Electrospray Ionization-Mass Spectrometry.

This work describes the application of the catch-and-release electrospray ionization-mass spectrometry (CaR-ESI-MS) assay, implemented using picodiscs (complexes comprised of saposin A and lipids, PDs), to screen mixtures of glycolipids (GLs) against water-soluble proteins to detect specific interactions. To demonstrate the reliability of the method, seven gangliosides (GM1, GM2, GM3, GD1a, GD1b, GD2, and GT1b) were incorporated, either individually or as a mixture, into PDs and screened against two lectins: the B subunit homopentamer of cholera toxin (CTB5) and a subfragment of toxin A from Clostridium difficile (TcdA-A2). The CaR-ESI-MS results revealed that CTB5 binds to six of the gangliosides (GM1, GM2, GM3, GD1a, GD1b, and GT1b), while TcdA-A2 binds to five of them (GM1, GM2, GM3, GD1a, and GT1b).

Liposome electrokinetic chromatography based in vitro model for early screening of the drug-induced phospholipidosis risk.

Drug-induced phospholipidosis (PLD) is a storage disorder of lysosomes characterized by the excessive accumulation of phospholipids as a result of improper medical treatments. Although few evidences have supported that PLD can induce significant pathological consequences, this potential toxicity indeed can put off the drug discovery process. In this research, a high-throughput liposome electrokinetic chromatography (LEKC) method was validated to evaluate the PLD risk of drug candidates by screening drug-phospholipid interaction, which correlates to the phospholipidosis inducing risk.

Nanodiscs and electrospray ionization mass spectrometry: a tool for screening glycolipids against proteins.

Electrospray ionization-mass spectrometry (ESI-MS) is extensively employed to detect and quantify protein-carbohydrate interactions in vitro and is increasingly used to screen carbohydrate libraries against target proteins. However, current ESI-MS methods are limited to carbohydrate ligands that are relatively soluble in water and are, therefore, not generally suitable for studying protein interactions with glycolipids, an important class of cellular receptors. Here, we describe a catch-and-release (CaR)-ESI-MS assay, which exploits nanodiscs (NDs) to solubilize glycolipids and mimic their natural cellular environment, suitable for screening libraries of glycosphingolipids (GSL) against proteins to identify specific interactions and to rank their relative affinities.

Synthesis of efficient N-containing TiO2 photocatalysts with high anatase thermal stability and the effects of the nitrogen residue on the photoinduced charge separation.

Efficient N-containing TiO(2) nanoparticles with high anatase thermal stability were synthesized via a hexamethylenetetramine (HMT)-modified sol-hydrothermal process. The results showed that modification with proper amounts of HMT is effective in increasing the onset temperature of the phase transformation of TiO(2) from anatase to rutile. The enhancement of the anatase thermal stability of the modified TiO(2) was attributed to ammonia produced slowly by hydrolysis of the HMT molecules in the sol-hydrothermal process and, additionally, to the residual nitrogen species after the thermal treatment at high temperatures, as indicated by the XPS examination.