The biosynthesis of the lincosamide antibiotics lincomycin A and celesticetin involves the pyridoxal-5'-phosphate (PLP)-dependent enzymes LmbF and CcbF, which are responsible for bifurcation of the biosynthetic pathways. Despite recognizing the same S-glycosyl-L-cysteine structure of the substrates, LmbF catalyses thiol formation through β-elimination, whereas CcbF produces S-acetaldehyde through decarboxylation-coupled oxidative deamination. The structural basis for the diversification mechanism remains largely unexplored. Here we conduct structure-function analyses of LmbF and CcbF. X-ray crystal structures, docking and molecular dynamics simulations reveal that active-site aromatic residues play important roles in controlling the substrate binding mode and the reaction outcome. Furthermore, the reaction selectivity and oxygen-utilization of LmbF and CcbF were rationally engineered through structure- and calculation-based mutagenesis. Thus, the catalytic function of CcbF was switched to that of LmbF, and, remarkably, both LmbF and CcbF variants gained the oxidative-amidation activity to produce an unnatural S-acetamide derivative of lincosamide.
Ecto-5'-nucleotidase (CD73) is a novel target in cancer (immuno)therapy. Its blockade prevents the formation of immunosuppressive and cancer-promoting adenosine from AMP. Here, we report on the development of a series of small molecules that mimic adenine nucleotides, in which the ribose moiety was replaced by an alkyl chain. Its length was found to be crucial for potency. A crystal structure of the N6-disubstituted acyclic ADP analog 26 (N6-benzyl,N6-methyladenine-9-yl)pentyloxydiphosphonate) in complex with human CD73 revealed that the flexible pentyl linker adopts to interdomain rotation angles differing by up to 18.5°. The most potent CD73 inhibitor of the present series was analog 27 (N6-benzyl,N6-methyladenine-9-yl)hexyloxydiphosphonate, PSB-24000) which exhibited submicromolar potency at human CD73 (Ki 563 nM at soluble CD73; Ki 481 nM at membrane-bound CD73 of triple-negative breast cancer cells). Acyclic nucleotide analogs may be advantageous compared to the previously reported nucleotidic CD73 inhibitors due to their high chemical stability, and because less off-target effects are to be expected. The structure-activity relationships discovered in this study provide valuable insights which will be useful for the development of CD73 inhibitors as immunotherapeutic drugs.
- MeSH
- 5'-Nucleotidase * antagonists & inhibitors metabolism MeSH
- Cisplatin chemistry pharmacology MeSH
- GPI-Linked Proteins antagonists & inhibitors metabolism MeSH
- Enzyme Inhibitors * pharmacology chemistry chemical synthesis MeSH
- Humans MeSH
- Models, Molecular MeSH
- Molecular Structure MeSH
- Purine Nucleotides * chemistry pharmacology chemical synthesis MeSH
- Pyrimidine Nucleotides * chemistry pharmacology chemical synthesis MeSH
- Dose-Response Relationship, Drug MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Krystaly indukované artropatie vznikají ukládáním depozit krystalů v kloubních strukturách. Nejčastěji se v klinické praxi setkáváme s ukládáním krystalů urátu sodného, což je příčinou dnavé artritis. Dnavá artritis v dospělosti představuje jedno z nejčastějších zánětlivých kloubních postižení. Zejména pak v rozvinuté části světa, kde v posledních letech vidíme trend k nárůstu tohoto onemocnění. Hlavní rizikový faktor pro vznik dnavé artritis představuje hyperurikemie, tedy patologické zvýšení hladiny kyseliny močové v krvi. Dnavá artritis ovlivňuje kvalitu života pacientů nejenom výraznou bolestivostí, ale i poměrně úzkým vztahem ke kardiovaskulárním komplikacím. V terapii využíváme jak farmakologické, tak nefarmakolo- gické postupy. Do komplexní terapie je nutno zahrnout i kontrolu systémových rizik choroby.
Crystal-induced arthropathy is caused by the deposition of crystal deposits in joint structures. Most often in clinical practice we encounter the deposition of sodium urate crystals, which is the cause of gouty arthritis. Gouty arthritis in adulthood is one of the most common inflammatory joint disorders. Especially in the developed part of the world, where in recent years we have seen a trend towards an increase in this disease. The main risk factor for the development of gouty arthritis is hyperuricemia, i.e. a pathological increase in the level of uric acid in the blood. Gouty arthritis affects the quality of life of patients not only by significant pain, but also by a relatively close relationship to cardiovascular complications. In therapy, we use both pharmacological and non-pharmacological procedures. Control of the systemic risks of the disease must also be included in the comprehensive therapy.
PSMA-617 is recognized as a benchmark ligand for prostate-specific membrane antigen (PSMA) owing to its broad utilization in prostate cancer (PCa) targeted radionuclide therapy. In this study, the structure-activity relationships (SAR) of PSMA-617 and two novel analogs featuring modified linkers were investigated. In compounds P17 and P18, the 2-naphthyl-l-Ala moiety was replaced with a less lipophilic 3-styryl-l-Ala moiety while the cyclohexyl ring in P18 was replaced with a phenyl group. The first ever crystal structure of the PSMA/PSMA-617 complex reported here revealed a folded conformation of the PSMA-617 linker while for the PSMA/P17 and PSMA/P18 complexes, the extended orientations of the linkers revealed linker flexibility within the PSMA cavity, a change in binding that can be exploited for the structure-guided design of PSMA-targeting agents. Despite structural differences from PSMA-617, the analogs maintained high PSMA inhibition potency, cellular binding, and internalization. In vivo biodistribution studies revealed comparable tumor uptake across all three compounds with P18 displaying higher spleen accumulation, likely due to phenyl ring lipophilicity. These SAR findings provide a strategic framework for the rational design of PSMA ligands, paving the way for the development of next-generation theranostic agents for PCa.
- Publication type
- Journal Article MeSH
TiO2 nanoparticles (NPs) are extensively used in various applications, highlighting the importance of ongoing research into their effects. This work belongs among rare whole-body inhalation studies investigating the effects of TiO2 NPs on mice. Unlike previous studies, the concentration of TiO2 NPs in the inhalation chamber (130.8 μg/m3) was significantly lower. This 11-week study on mice confirmed in vivo the presence of TiO2 NPs in lung macrophages and type II pneumocytes including their intracellular localization by using the electron microscopy and the state-of-the-art methods detecting NPs' chemical identity/crystal structure, such as the energy-dispersed X-ray spectroscopy (EDX), cathodoluminescence (CL), and detailed diffraction pattern analysis using powder nanobeam diffraction (PNBD). For the first time in inhalation study in vivo, the alterations in erythrocyte morphology with evidence of echinocytes and stomatocytes, accompanied by iron accumulation in spleen, liver, and kidney, are reported following NP's exposure. Together with the histopathological evidence of hyperaemia in the spleen and kidney, and haemosiderin presence in the spleen, the finding of NPs containing iron might suggest the increased decomposition of damaged erythrocytes. The detection of TiO2 NPs on erythrocytes through CL analysis confirmed their potential systemic availability. On the contrary, TiO2 NPs were not confirmed in other organs (spleen, liver, and kidney); Ti was detected only in the kidney near the detection limit.
- MeSH
- Administration, Inhalation MeSH
- Erythrocytes * drug effects pathology MeSH
- Inhalation Exposure * adverse effects MeSH
- Metal Nanoparticles * toxicity MeSH
- Mice MeSH
- Nanoparticles * toxicity MeSH
- Lung * drug effects metabolism pathology MeSH
- Toxicity Tests, Subchronic MeSH
- Titanium * toxicity pharmacokinetics administration & dosage MeSH
- Tissue Distribution MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Due to their attractive band gap properties and van der Waals structure, 2D binary chalcogenide materials have been widely investigated in the last decade, finding applications in several fields such as catalysis, spintronics, and optoelectronics. Ternary 2D chalcogenide materials are a subject of growing interest in materials science due to their superior chemical tunability which endows tailored properties to the devices prepared thereof. In the family of AIIBIII2XVI4, ordered ZnIn2S4-like based photocatalytic systems have been studied meticulously. In contrast, reports on disordered phases appear to a minor extent. Herein, a photoelectrochemical (PEC) detector based on the pseudo-binary MnIn2Se4 system is presented. A combination of optical measurements and DFT calculations confirmed that the nature of the bandgap in MnIn2Se4 is indirect. Its performance outclasses that of parent compounds, reaching responsivity values of 8.41 mA W-1. The role of the non-centrosymmetric crystal structure is briefly discussed as a possible cause of improved charge separation of the photogenerated charge carriers.
- Publication type
- Journal Article MeSH
INTRODUCTION: Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. is used in traditional medicine for various purposes. Previous phytochemical studies focused on phenolic compounds, but triterpenoids were almost overlooked. OBJECTIVE: The study focused on the isolation of compounds with dual antidiabetic activity from the aerial parts of Z. clinopodioides subsp. bungeana. MATERIALS AND METHODS: Separation of CHCl3-soluble fraction by silica gel column chromatography using different mobile phases and purification of compounds by semi-preparative HPLC or preparative TLC. The structures of pure compounds were elucidated by 1D and 2D NMR experiments along with HRMS. Compound 1 was additionally identified by the single crystal X-ray diffraction method. α-Glucosidase inhibitory assay and GLUT4 expression and translocation in C2C12 myotubes were conducted to evaluate antidiabetic potential of isolated compounds. RESULTS: This phytochemical study led to the isolation of 20 compounds, including a unique monoterpene diperoxy dimer (1). Compounds 7 and 9-11 displayed more potent α-glucosidase inhibitory activity (IC50 45.3-135.3 μM) than acarbose used as a positive control (IC50 264.7 μM), while only pomolic acid (5) increased GLUT4 translocation in C2C12 myotubes in a significant manner. CONCLUSION: Extensive chromatographic separation led to the isolation and identification of a unique monoterpene diperoxy dimer (1) from aerial parts of Z. clinopodioides subsp. bungeana. Some triterpenes inhibited α-glucosidase, another increased GLUT4 translocation. Although none of the isolated compounds demonstrated dual antidiabetic activity, selected triterpenes proved to be potent antidiabetic agents in vitro.
- MeSH
- alpha-Glucosidases metabolism MeSH
- Cell Line MeSH
- Lamiaceae * chemistry MeSH
- Hypoglycemic Agents * pharmacology chemistry isolation & purification MeSH
- Glycoside Hydrolase Inhibitors pharmacology isolation & purification chemistry MeSH
- Mice MeSH
- Plant Components, Aerial chemistry MeSH
- Glucose Transporter Type 4 metabolism MeSH
- Plant Extracts chemistry pharmacology MeSH
- Triterpenes * pharmacology chemistry isolation & purification MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Nanocrystalline cerium dioxide is able to protect living cells from oxidative stress under the influence of various stress factors, in particular under the one of low temperatures. This study investigates the phase-structural transformations in aqueous solutions containing CeO2 nanoparticles (NPs) and their impact on the cryopreservation process. Differential scanning calorimetry and thermomechanical analysis were used to analyse the phase transitions in aqueous suspensions of CeO2 NPs and aqueous solutions of the cryoprotectant dimethyl sulfoxide (Me2SO) with CeO2 NPs. Various concentrations of CeO2 NPs were tested to observe their effects on the crystallization and melting behaviours. The addition of CeO2 NPs significantly altered the temperatures and enthalpies of melting and crystallization in water. Low concentrations of CeO2 NPs promoted crystallization, while higher concentrations inhibited it, reducing supercooling and recrystallization during thawing. In Me2SO solutions, CeO2 NPs raised the glass transition temperature and affected the recrystallization process, with higher concentrations leading to more pronounced vitrification and reduced recrystallization. We also investigated the regularities of the effect of CeO2 NPs on phase transitions in combined cryoprotective media with Ham's F12, fetal bovine serum and Me2SO, which can be used in future to design the cryopreservation protocols. In the complex media, CeO2 NPs decreased the metastability and altered eutectic crystallization patterns, indicating potential cryoprotective effects. In conclusion, CeO2 NPs modulate the thermophysical properties of cryoprotective solutions, enhancing vitrification and reducing recrystallization, which could improve cryopreservation efficiency. Optimizing NP concentrations is crucial for practical applications in cryopreservation.
- MeSH
- Cerium * chemistry pharmacology MeSH
- Calorimetry, Differential Scanning * MeSH
- Dimethyl Sulfoxide * chemistry MeSH
- Cryopreservation * methods MeSH
- Cryoprotective Agents * chemistry pharmacology MeSH
- Crystallization * MeSH
- Nanoparticles * chemistry MeSH
- Transition Temperature MeSH
- Vitrification * drug effects MeSH
- Phase Transition * MeSH
- Publication type
- Journal Article MeSH
The pregnane X receptor (PXR) is a key regulator of metabolism, but the mechanisms underlying its antagonism remain unclear. Garcia-Maldonado et al. reported potent new antagonists and their co-crystal structures, revealing molecular determinants of PXR antagonism and paving the way for developing antagonists as therapeutics and preventing undesirable PXR activation.
- MeSH
- Humans MeSH
- Pregnane X Receptor * antagonists & inhibitors metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Lens epithelium-derived growth factor p75 (LEDGF/p75), member of the hepatoma-derived growth-factor-related protein (HRP) family, is a transcriptional co-activator and involved in several pathologies including HIV infection and malignancies such as MLL-rearranged leukemia. LEDGF/p75 acts by tethering proteins to the chromatin through its integrase binding domain. This chromatin interaction occurs between the PWWP domain of LEDGF/p75 and nucleosomes carrying a di- or trimethylation mark on histone H3 Lys36 (H3K36me2/3). Our aim is to rationally devise small molecule drugs capable of inhibiting such interaction. To bootstrap this development, we resorted to X-ray crystallography-based fragment screening (FBS-X). Given that the LEDGF PWWP domain crystals were not suitable for FBS-X, we employed crystals of the closely related PWWP domain of paralog HRP-2. As a result, as many as 68 diverse fragment hits were identified, providing a detailed sampling of the H3K36me2/3 pocket pharmacophore. Subsequent structure-guided fragment expansion in three directions yielded multiple compound series binding to the pocket, as verified through X-ray crystallography, nuclear magnetic resonance and differential scanning fluorimetry. Our best compounds have double-digit micromolar affinity and optimally sample the interactions available in the pocket, judging by the Kd-based ligand efficiency exceeding 0.5 kcal/mol per non-hydrogen atom. Beyond π-stacking within the aromatic cage of the pocket and hydrogen bonding, the best compounds engage in a σ-hole interaction between a halogen atom and a conserved water buried deep in the pocket. Notably, the binding pocket in LEDGF PWWP is considerably smaller compared to the related PWWP1 domains of NSD2 and NSD3 which feature an additional subpocket and for which nanomolar affinity compounds have been developed recently. The absence of this subpocket in LEDGF PWWP limits the attainable affinity. Additionally, these structural differences in the H3K36me2/3 pocket across the PWWP domain family translate into a distinct selectivity of the compounds we developed. Our top-ranked compounds are interacting with both homologous LEDGF and HRP-2 PWWP domains, yet they showed no affinity for the NSD2 PWWP1 and BRPF2 PWWP domains which belong to other PWWP domain subfamilies. Nevertheless, our developed compound series provide a strong foundation for future drug discovery targeting the LEDGF PWWP domain as they can further be explored through combinatorial chemistry. Given that the affinity of H3K36me2/3 nucleosomes to LEDGF/p75 is driven by interactions within the pocket as well as with the DNA-binding residues, we suggest that future compound development should target the latter region as well. Beyond drug discovery, our compounds can be employed to devise tool compounds to investigate the mechanism of LEDGF/p75 in epigenetic regulation.
- MeSH
- Small Molecule Libraries chemistry pharmacology chemical synthesis MeSH
- Crystallography, X-Ray MeSH
- Humans MeSH
- Intercellular Signaling Peptides and Proteins metabolism chemistry MeSH
- Models, Molecular MeSH
- Molecular Structure MeSH
- Protein Domains MeSH
- Drug Design * MeSH
- Dose-Response Relationship, Drug MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
