Structural, Biochemical, and Computational Characterization of Sulfamides as Bimetallic Peptidase Inhibitors.

The sulfonamide function is used extensively as a general building block in various inhibitory scaffolds and, more specifically, as a zinc-binding group (ZBG) of metalloenzyme inhibitors. Here, we provide biochemical, structural, and computational characterization of a metallopeptidase in complex with inhibitors, where the mono- and bisubstituted sulfamide functions are designed to directly engage zinc ions of a bimetallic enzyme site. Structural data showed that while monosubstituted sulfamides coordinate active-site zinc ions via the free negatively charged amino group in a canonical manner, their bisubstituted counterparts adopt an atypical binding pattern divergent from expected positioning of corresponding tetrahedral reaction intermediates. Accompanying quantum mechanics calculations revealed that electroneutrality of the sulfamide function is a major factor contributing to the markedly lower potency of bisubstituted compounds by considerably lowering their interaction energy with the enzyme. Overall, while bisubstituted uncharged sulfamide functions can bolster favorable pharmacological properties of a given inhibitor, their use as ZBGs in metalloenzyme inhibitors might be less advantageous due to their suboptimal metal-ligand properties.

Conformational analysis of amphetamine and methamphetamine: a comprehensive approach by vibrational and chiroptical spectroscopy.

After cannabis, the most commonly used illicit substance worldwide is amphetamine and its derivatives, such as methamphetamine, with an ever-increasing number of synthetic modifications. Thus, fast and reliable methods are needed to identify them according to their spectral patterns and structures. Here, we have investigated the use of molecular spectroscopy methods to describe the 3D structures of these substances in a solution that models the physiological environment. The substances were analyzed by Raman and infrared (IR) absorption spectroscopy and by chiroptical methods, vibrational circular dichroism (VCD) and Raman optical activity (ROA). The obtained experimental data were supported by three different computational approaches based on density functional theory (DFT) and molecular dynamics (MD). Successful interpretation relies on good agreement between experimental and predicted spectra. The determination of the conformer populations of the studied molecules was based on maximizing the similarity overlap of weighted conformer spectra by a global minimization algorithm. Very good agreement was obtained between the experimental spectra and optimized-population weighted spectra from MD, providing a detailed insight into the structure of the molecules and their interaction with the solvent. The relative population of three amphetamine and six methamphetamine conformers was determined and is consistent with a previous NMR study. However, this work shows that only a few isolated conformers are not sufficient for the successful interpretation of the spectra, but the entire conformational space needs to be sampled appropriately and explicit interaction with the solvent needs to be included.

Paramagnetic encoding of molecules.

Contactless digital tags are increasingly penetrating into many areas of human activities. Digitalization of our environment requires an ever growing number of objects to be identified and tracked with machine-readable labels. Molecules offer immense potential to serve for this purpose, but our ability to write, read, and communicate molecular code with current technology remains limited. Here we show that magnetic patterns can be synthetically encoded into stable molecular scaffolds with paramagnetic lanthanide ions to write digital code into molecules and their mixtures. Owing to the directional character of magnetic susceptibility tensors, each sequence of lanthanides built into one molecule produces a unique magnetic outcome. Multiplexing of the encoded molecules provides a high number of codes that grows double-exponentially with the number of available paramagnetic ions. The codes are readable by nuclear magnetic resonance in the radiofrequency (RF) spectrum, analogously to the macroscopic technology of RF identification. A prototype molecular system capable of 16-bit (65,535 codes) encoding is presented. Future optimized systems can conceivably provide 64-bit (~10^19 codes) or higher encoding to cover the labelling needs in drug discovery, anti-counterfeiting and other areas.

25CN-NBOMe Metabolites in Rat Urine, Human Liver Microsomes and C.elegans-Structure Determination and Synthesis of the Most Abundant Metabolites.

N-Benzylphenethylamines are novel psychedelic substances increasingly used for research, diagnostic, or recreational purposes. To date, only a few metabolism studies have been conducted for N-2-methoxybenzylated compounds (NBOMes). Thus, the available 2,5-dimethoxy-4-(2-((2-methoxybenzyl)amino)ethyl)benzonitrile (25CN-NBOMe) metabolism data are limited. Herein, we investigated the metabolic profile of 25CN-NBOMe in vivo in rats and in vitro in Cunninghamella elegans (C. elegans) mycelium and human liver microsomes. Phase I and phase II metabolites were first detected in an untargeted screening, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) identification of the most abundant metabolites by comparison with in-house synthesized reference materials. The major metabolic pathways described within this study (mono- and bis-O-demethylation, hydroxylation at different positions, and combinations thereof, followed by the glucuronidation, sulfation, and/or N-acetylation of primary metabolites) generally correspond to the results of previously reported metabolism of several other NBOMes. The cyano functional group was either hydrolyzed to the respective amide or carboxylic acid or remained untouched. Differences between species should be taken into account in studies of the metabolism of novel substances.

Effect of physicochemical parameters on the stability and activity of garlic alliinase and its use for in-situ allicin synthesis.

Garlic is a well-known example of natural self-defence system consisting of an inactive substrate (alliin) and enzyme (alliinase) which, when combined, produce highly antimicrobial allicin. Increase of alliinase stability and its activity are of paramount importance in various applications relying on its use for in-situ synthesis of allicin or its analogues, e.g., pulmonary drug delivery, treatment of superficial injuries, or urease inhibitors in fertilizers. Here, we discuss the effect of temperature, pH, buffers, salts, and additives, i.e. antioxidants, chelating agents, reducing agents and cosolvents, on the stability and the activity of alliinase extracted from garlic. The effects of the storage temperature and relative humidity on the stability of lyophilized alliinase was demonstrated. A combination of the short half-life, high reactivity and non-specificity to particular proteins are reasons most bacteria cannot deal with allicin's mode of action and develop effective defence mechanism, which could be the key to sustainable drug design addressing serious problems with escalating emergence of multidrug-resistant (MDR) bacterial strains.

Stability of psilocybin and its four analogs in the biomass of the psychotropic mushroom Psilocybe cubensis.

Psilocybin, psilocin, baeocystin, norbaeocystin, and aeruginascin are tryptamines structurally similar to the neurotransmitter serotonin. Psilocybin and its pharmacologically active metabolite psilocin in particular are known for their psychoactive effects. These substances typically occur in most species of the genus Psilocybe (Fungi, Strophariaceae). Even the sclerotia of some of these fungi known as "magic truffles" are of growing interest in microdosing due to them improving cognitive function studies. In addition to microdosing studies, psilocybin has also been applied in clinical studies, but only its pure form has been administrated so far. Moreover, the determination of tryptamine alkaloids is used in forensic analysis. In this study, freshly cultivated fruit bodies of Psilocybe cubensis were used for monitoring stability (including storage and processing conditions of fruiting bodies). Furthermore, mycelium and the individual parts of the fruiting bodies (caps, stipes, and basidiospores) were also examined. The concentration of tryptamines in final extracts was analyzed using ultra-high-performance liquid chromatography coupled with mass spectrometry. No tryptamines were detected in the basidiospores, and only psilocin was present at 0.47 wt.% in the mycelium. The stipes contained approximately half the amount of tryptamine alkaloids (0.52 wt.%) than the caps (1.03 wt.%); however, these results were not statistically significant, as the concentration of tryptamines in individual fruiting bodies is highly variable. The storage conditions showed that the highest degradation of tryptamines was seen in fresh mushrooms stored at -80°C, and the lowest decay was seen in dried biomass stored in the dark at room temperature.

Enantioseparation and Determination of Mephedrone and Its Metabolites by Capillary Electrophoresis Using Cyclodextrins as Chiral Selectors.

Mephedrone, a psychoactive compound derived from cathinone, is widely used as a designer drug. The determination of mephedrone and its metabolites is important for understanding its possible use in medicine. In this work, a method of capillary electrophoresis for the chiral separation of mephedrone and its metabolites was developed. Carboxymethylated ß-cyclodextrin was selected as the most effective chiral selector from seven tested cyclodextrin derivates. Based on the simplex method, the optimal composition of the background electrolyte was determined: at pH 2.75 and 7.5 mmol·L-1 carboxymethylated ß-cyclodextrin the highest total resolution of a mixture of analytes was achieved. For mephedrone and its metabolites, calibration curves were constructed in a calibration range from 0.2 to 5 mmol·L-1; limits of detection, limits of quantification, precision, and repeatability were calculated, and according to Mandel's fitting test, the linear calibration ranges were determined.

Use of novel haptens in the production of antibodies for the detection of tryptamines.

Tryptamines are a group of hallucinogenic drugs whose detection in body fluids could be simplified by immunochemical assay kits. Antibodies for these assays are obtained by the immunization of laboratory animals with conjugates of a hapten similar to the target analyte and a suitable protein. Therefore we synthesized novel haptens derived from tryptamine-based drugs, with N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and N,N-diisopropyltryptamine (DiPT) selected as the target analytes. Their structures were modified with a short linker ended with a carboxylic group. The haptens were conjugated with bovine serum albumin (BSA) and rabbits were immunized with the conjugates. The obtained polyclonal antibodies showed good reactivity and the LOD of the constructed ELISAs was in the range 0.006-0.254 ng mL-1. Thus, they are suitable for the development of immunochemical assay kits.

Efficiency and stability of spectral sensitization of boron-doped-diamond electrodes through covalent anchoring of a donor-acceptor organic chromophore (P1).

A novel procedure is developed for chemical modification of H-terminated B-doped diamond surfaces with a donor-π-bridge-acceptor molecule (P1). A cathodic photocurrent near 1 µA cm(-2) flows under 1 Sun (AM 1.5) illumination at the interface between the diamond electrode and aqueous electrolyte solution containing dimethylviologen (electron mediator). The efficiency of this new electrode outperforms that of the non-covalently modified diamond with the same dye. The found external quantum efficiency of the P1-sensitized diamond is not far from that of the flat titania electrode sensitized by a standard organometallic dye used in solar cells. However, the P1 dye, both pure and diamond-anchored, shows significant instability during illumination by solar light. The degradation is a two-stage process in which the initially photo-generated products further decompose in complicated dark reactions. These findings need to be taken into account for optimization of organic chromophores for solar cells in general.