The Impact of Terminal Peptide Extensions of Retinal Inosine 5´Monophosphate Dehydrogenase 1 Isoforms on their DNA-binding Activities.

The main structural difference between the mutation-susceptible retinal isoforms of inosine 5´-monophosphate dehydrogenase-1 (IMPDH-1) with the canonical form resides in the C- and N-terminal peptide extensions with unknown structural/functional impacts. In this report, we aimed to experimentally evaluate the functional impact of these extensions on the specific/non-specific single-stranded DNA (ssDNA)-binding activities relative to those of the canonical form. Our in silico findings indicated the possible contribution of the C-terminal segment to the reduced flexibility of the Bateman domain of the enzyme. In addition, the in silico data indicated that the N-terminal tail acts by altering the distance between the tetramers in the concave octamer complex (the native form) of the enzyme. The overall impact of these predicted structural variations became evident, first, through higher Km values with respect to either of the substrates relative to the canonical isoform, as reported previously (Andashti et al. in Mol Cell Biochem 465(1):155-164, 2020). Secondary, the binding of the recombinant mouse retinal isoform IMPDH1 (603) to its specific Rhodopsin target gene was significantly augmented while its binding to non-specific ssDNA was lower than that of the canonical isoform. The DNA-binding activity of the other mouse retinal isoform, IMPDH1(546), to specific and non-specific ssDNA was lower than that of the canonical form most probably due to the in silico predicted rigidity created in the Bateman domain by the C-terminal peptide extension. Furthermore, the DNA binding to the Rhodopsin target gene by each of the IMPDH isoforms influenced in the presence of GTP (Guanosine triphosphate) and ATP (Adenosine triphosphate).

Determining the potential targets of silybin by molecular docking and its antibacterial functions on efflux pumps and porins in uropathogenic E. coli.

BACKGROUND: One of the causes of antibiotic resistance is the reduced accumulation of antibiotics in bacterial cells through pumping out the drugs. Silybin, a key component of the Silybum marianum plant, exhibits various beneficial properties, including anti-bacterial, anti-inflammatory, antioxidant, and hepatoprotective effects. METHODS AND RESULTS: Clinical isolates of E. coli were procured from 17 Shahrivar Children's Hospital in Rasht, Guilan, located in northern Iran. Their susceptibility to six antibiotics was assessed using disc diffusion and broth dilution (MIC) methods. The antibacterial effects of silybin-loaded polymersome nanoparticles (SPNs) were investigated with broth dilution (MIC) and biofilm assays. Molecular docking was utilized to evaluate silybin's (the antibacterial component) binding affinity to efflux pumps, porins, and their regulatory elements. Additionally, qRT-PCR analysis explored the expression patterns of acrA, acrB, tolC, ompC, and ompF genes in both SPNs (sub-MIC) and ciprofloxacin (sub-MIC)-treated and untreated E. coli isolates. The combined use of SPNs and ciprofloxacin exhibited a notable reduction in bacterial growth and biofilm formation, in ciprofloxacin-resistant isolates. The study identified eight overlapping binding sites of the AcrABZ-TolC efflux pump in association with silybin, demonstrating a binding affinity ranging from -7.688 to -10.33 Kcal/mol. Furthermore, the qRT-PCR analysis showed that silybin upregulated AcrAB-TolC efflux pump genes and downregulated ompC and ompF porin genes in combination with ciprofloxacin in transcriptional level in uropathogenic E. coli. CONCLUSIONS: Silybin, a safe herbal compound, exhibits potential in inhibiting antibiotic resistance within bacterial isolates, potentially through the regulation of gene expression and plausible binding to target proteins.

Simulation and practical investigation of carbonic anhydrase stability in an industrial solvent system of methyl diethanolamine for carbon dioxide capture.

Carbonic anhydrase owing to its potential as an industrial biocatalyst for carbon dioxide sequestration from flue gas has attracted considerable attention in solving global warming problems. A large body of research has been conducted to increase the thermal stability of carbonic anhydrase from different sources against the harsh operational conditions of CO2 capture systems. In contrast to cost-intensive protein engineering methods, solvation with aqueous-organic binary mixtures offers a convenient and economical alternative strategy for retention of protein structure and stability. This study aimed to examine the stabilizing effect of methyl diethanolamine (MDEA) as a component of an aqueous-organic solvent mixture on human carbonic anhydrase II (HCA II) at extreme temperatures. Computational and also spectroscopic examinations were employed for tracking conformational changes and stability evaluation of HCA II in 50:50 (vol %) water: MDEA binary mixture at high temperature. Molecular dynamic (MD) simulation studies predicted the high thermal stability of HCA II in the presence of MDEA. UV absorbance spectra confirmed the thermo-stabilizing effect of the binary solvent mixture on HCA II. While the enzymatic activity of HCA II at 25 °C in the presence of 10, 25, and 50 (vol%) of MDEA was substantially increased, no obvious effect on retention of HCA II activity in the water-MDEA binary solvent mixture at 85 °C was seen. It is shown that the solvation of HCA II in the presence of MDEA could result in the prevention of aggregate formation in high temperatures but not functional stability.Communicated by Ramaswamy H. Sarma.

Identifying potent inhibitory phytocompounds from Lagerstroemia speciosa against SARS-Coronavirus-2: structure-based virtual screening.

The ongoing spillover of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) calls for expedited countermeasure through developing therapeutics from natural reservoirs and/or the use of less time-consuming drug discovery methodologies. This study aims to apply these approaches to identify potential blockers of the virus from the longstanding medicinal herb, Lagerstroemia speciosa, through comprehensive computational-based screening. Nineteen out of 22 L. speciosa phytochemicals were selected on the basis of their pharmacokinetic properties. SARS-CoV-2 Main protease (Mpro), RNA-directed RNA polymerase (RdRp), Envelope viroporin protein (Evp) and receptor-binding domain of Spike glycoprotein (S-RBD), as well as the human receptor Angiotensin-converting enzyme-2 (hACE2) were chosen as targets. The screening was performed by molecular docking, followed by 100-ns molecular dynamic simulations and free energy calculations. 24-Methylene cycloartanol acetate (24MCA) was found as the best inhibitor for both Evp and RdRp, and sitosterol acetate (SA) as the best hit for Mpro, S-RBD and hACE2. Dynamic simulations, binding mode analyses, free energy terms and share of key amino acids in protein-drug interactions confirmed the stable binding of these phytocompounds to the hotspot sites on the target proteins. With their possible multi-targeting capability, the introduced phytoligands might offer promising lead compounds for persistent fight with the rapidly evolving coronavirus. Therefore, experimental verification of their safety and efficacy is recommended.

The effect of chronic lithium treatment on hippocampal progenitor cells: Transcriptomic analysis and systems pharmacology.

OBJECTIVE: To identify the genomics underpinning the increased volume of the hippocampus after long-term administration of lithium (Li) in bipolar disorder patients, hypothesizing the possible contribution of cell growth and differentiation pathways to this complication. METHODS: RNA-seq profiles of four samples of hippocampal progenitor cells chronically treated with a high dose of Li and three samples chronically treated with the therapeutic dose were retrieved from NCBI-GEO. The raw data underwent filtration, quality control, expression fold change, adjusted significance, functional enrichment, and pharmacogenomic analyses. RESULTS: CCND1, LOXL2, and PRNP were identified as the genes involved in the drug response and the chronic effects of Li in the hippocampal cells. GSK-3ß was also a hub in the pharmacogenomic network of Li. In addition, ZMPSTE24 and DHX35 were identified as the important genes in lithium therapy. CONCLUSIONS: As shown by gene ontology results, these findings conclude that lithium may increase the size of the hippocampus in bipolar patients by stimulating the generation of new neurons and promoting their differentiation into neuroblasts, neurons, or microglia.

Virtual screening of natural ligands from five resources to target Ralstonia solanacearum polygalacturonase and endoglucanase.

The present computational study explores novel herbal compounds with potent inhibitory activity against polygalacturonase (PG) and endoglucanase (EG), the extracellular cell wall-degrading enzymes of Ralstonia solanacearum causing crops' bacterial wilt. Phytocompounds of Rosmarinus officinalis L., Coriandrum sativum L., Ocimum basilicum, Cymbopogon citratus, and Thymus vulgaris were first checked to be pharmacokinetically safe and nontoxic. The ligands were then docked to predicted and validated structural models of PG and EG. Molecular dynamic simulations were performed to ensure the dynamic stability of protein-ligand complexes. Carvone and citronellyl acetate were identified to have the best docking energy in binding and inhibiting PG and EG, respectively. In molecular dynamics, root-mean-square deviations of PG-Carvone and EG-Citronellyl acetate complexes indicated the high stability of the ligands in their corresponding cavities. Root-mean-square fluctuations of both proteins indicated unchanged mobility of the binding site residues due to a stable interaction with their ligands. Functional groups on both ligands contributed to the formation of hydrogen bonds with their respective proteins, which were preserved throughout the simulation time. The nonpolar energy component was revealed to significantly contribute to the stability of the docked protein-ligand complexes. Overall, our findings imply the high capability of Carvone and Citronellyl acetate as strong pesticides against the R. solanacearum-caused wilt. This study highlighted the potential of natural ligands in controlling the agricultural bacterial infections, as well as the utility of computational screening techniques in discovering appropriate and potent lead compounds. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03683-z.

Gene cloning and characterization of a novel recombinant 40-kDa heat shock protein from Mesobacillus persicus B48.

The present study reports the recognition and characterization of the gene encoding the co-chaperone DnaJ in the halophilic strain Mesobacillus persicus B48. The new extracted gene was sequenced and cloned in E. coli, followed by protein purification using a C-terminal His-tag. The stability and function of the recombinant DnaJ protein under salt and pH stress conditions were evaluated. SDS-PAGE revealed a band on nearly 40-kDa region. The homology model structure of new DnaJ demonstrated 56% similarity to the same protein from Streptococcus pneumonia. Fluorescence spectra indicated several hydrophobic residues located on the protein surface, which is consistent with the misfolded polypeptide recognition function of DnaJ. Spectroscopic results showed 56% higher carbonic anhydrase activity in the presence of the recombinant DnaJ homolog compared to its absence. In addition, salt resistance experiments showed that the survival of recombinant E. coli+DnaJ was 2.1 times more than control cells in 0.5 M NaCl. Furthermore, the number of recombinant E. coli BL21+DnaJ colonies was 7.7 times that of the control colonies in pH 8.5. Based on the results, DnaJ from the M. persicus can potentially be employed for improving the functional features of enzymes and other proteins in various applications.

Tumor-targeted induction of intrinsic apoptosis in colon cancer cells by Lactobacillus plantarum and Lactobacillus rhamnosus strains.

BACKGROUND: Colorectal cancer is one of the widespread and lethal types of malignancies. Recently, antineoplastic attributes of probiotics have attracted lots of attention. Here, we investigated anti-proliferative potential of the non-pathogenic strains Lactobacillus plantarum ATCC 14,917 and Lactobacillus rhamnosus ATCC 7469 on human colorectal adenocarcinoma-originated Caco-2 cells. METHODS AND RESULTS: Caco-2 and HUVEC control cells were treated with ethyl acetate extracts of the two Lactobacillus strains to assess cell viability by MTT assay. Annexin/PI staining flow cytometry, and caspase-3, -8 and - 9 activity assays were performed to determine the type of cell death induced in extract-treated cells. Expression levels of apoptosis-related genes were evaluated by RT-PCR. Extracts from both L. plantarum and L. rhamnosus specifically targeted the Caco-2 cells and not HUVEC controls, and significantly affected the viability of the colon cancer cell line in a time- and dose-dependent manner. This effect was shown to occur through activation of the intrinsic apoptosis pathway, as indicated by the increased caspase-3 and - 9 activities. While there are limited and conflicting data about the mechanisms underlying the specific antineoplastic attributes of Lactobacillus strains, we clarified the overall induced mechanism. The Lactobacillus extracts specifically down-regulated the expression of the anti-apoptotic bcl-2 and bcl-xl, and simultaneously up-regulated the pro-apoptotic bak, bad, and bax genes in treated Caco-2 cells. CONCLUSIONS: Ethyl acetate extracts of L. plantarum and L. rhamnosus strains could be considered as targeted anti-cancer treatments specifically inducing the intrinsic apoptosis pathway in colorectal tumor cells.

Gentamycin Rationally Repositioned to Inhibit miR-34a Ameliorates Oxidative Injury to PC12 Cells.

Ischemic stroke accompanies oxidative stress and cell death in the cerebral tissue. The microRNA miR-34a plays a pivotal role in this molecular pathology. This study presents the rational repositioning of aminoglycosidic antibiotics as miR-34a antagonists in order to assess their efficiency in protecting the PC12 stroke model cells from oxidative stress occurring under cerebral ischemic conditions. A library of 29 amino-sugar compounds were screened against anticipated structural models of miR-34a through molecular docking. MiR-ligand interactions were mechanistically studied by molecular dynamics simulations and free-energy calculations. Cultured PC12 cells were treated by H2O2 alone or in combination with gentamycin and neomycin as selected drugs. Cell viability and apoptosis were detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) and annexin V-FITC/propidium iodate (PI) double staining assays, respectively. The expression levels of key factors involved in cell proliferation, oxidative stress, and apoptosis in treated PC12 cells were measured through a quantitative real-time polymerase chain reaction and flow cytometric annexin V-FITC/PI double staining assays. A stable and energetically favorable binding was observed for miR-34a with gentamycin and neomycin. Gentamycin pretreatments followed by H2O2 oxidative injury led to increased cell viability and protected PC12 cells against H2O2-induced apoptotic events. This study will help in further understanding how the suppression of miR-34a in neural tissue affects the cell viability upon stroke.

Advanced simulations and screening to repurposing a 3C protease inhibitor against the rupintrivir-resistant human norovirus-induced gastroenteritis.

Human norovirus (HuNoV) causes acute viral gastroenteritis in all age groups, and dehydration and severe diarrhea in the elderly. The World Health Organization reports ∼1.45 million deaths from acute gastroenteritis annually in the world. Rupintrivir, an inhibitory medicine against the human rhinovirus C3 protease, has been reported to inhibit HuNoV 3C protease. However, several HuNoV 3C protease mutations have been revealed to reduce the susceptibility of HuNoV to rupintrivir. The structural details behind rupintrivir-resistance of these single-point mutations (A105V and I109V) are not still clear. Hence, in this study, a combination of computational techniques were used to determine the rupintrivir-resistance mechanism and to propose an inhibitor against wild-type and mutant HuNoV 3C protease through structure-based virtual screening. Dynamic structural results indicated the unstable binding of rupintrivir at the cleft binding site of the wild-type and mutant 3C proteases, leading to its detachment. Our findings presented that the domain II of the HuNoV 3C protease had a critical role in binding of inhibitory molecules. Binding energy computations, steered molecular dynamics and umbrella sampling simulations confirmed that amentoflavone, the novel suggested inhibitor, strongly binds to the cleft site of all protease models and has a good structural stability in the complex system along the molecular dynamic simulations. Our in silico study proposed the selected compound as a potential inhibitor against the HuNoV 3C protease. However, additional experimental and clinical studies are required to corroborate the therapeutic efficacy of the compound.

Design of a novel multi-epitope vaccine candidate against hepatitis C virus using structural and nonstructural proteins: An immunoinformatics approach.

Hepatitis C virus (HCV) infects the liver and causes chronic infection. Several mutations in the viral genome have been associated with drug resistance development. Currently, there is no approved vaccine against the HCV. The employment of computational biology is the primary and crucial step for vaccine design or antiviral therapy which can substantially reduce the duration and cost of studies. Therefore, in this study, we designed a multi-epitope vaccine using various immunoinformatics tools to elicit the efficient human immune responses against the HCV. Initially, various potential (antigenic, immunogenic, non-toxic and non-allergenic) epitope segments were extracted from viral structural and non-structural protein sequences using multiple screening methods. The selected epitopes were linked to each other properly. Then, toll-like receptors (TLRs) 3 and 4 agonists (50S ribosomal protein L7/L12 and human ß-defensin 2, respectively) were added to the N-terminus of the final vaccine sequence to increase its immunogenicity. The 3D structure of the vaccine was modeled. Molecular dynamics simulations studies verified the high stability of final free vaccines and in complex with TLR3 and TLR4. These constructs were also antigenic, non-allergenic, nontoxic and immunogenic. Although the designed vaccine traits were promising as a potential candidate against the HCV infection, experimental studies and clinical trials are required to verify the protective traits and safety of the designed vaccine.

Efflux dynamics of the antiseizure drug, levetiracetam, through the P-glycoprotein channel revealed by advanced comparative molecular simulations.

Understanding the precise mechanistic details of the possible binding and transport of antiseizure medications (ASMs) through the P-glycoprotein (P-gp) efflux pump is essential to find strategies for the treatment of patients with epilepsy resistant to ASMs. In the present work, conventional molecular dynamics, binding free energy calculations, steered molecular dynamics and umbrella sampling were applied to study the interactions of levetiracetam and brivaracetam with P-gp and their possible egress path from the binding site. Comparative results for the control drugs, zosuquidar and verapamil, confirmed their established P-gp inhibitory activity. Brivaracetam, a non-substrate of P-gp, demonstrated stronger static and dynamic interactions with the exporter protein, than levetiracetam. The potential of mean force calculations indicated that the energy barriers through the ligand export were the lowest for levetiracetam, suggesting the drug as a P-gp substrate with facile passage through the transporter channel. Our findings also stressed the contribution of nonpolar interactions with P-gp channel lining as well as with membrane lipid molecules to hamper the ASM efflux by the transmembrane exporter. Appropriate structural engineering of the ASMs is thus recommended to address drug-resistant epilepsy.

Rational design of a new variant of Reteplase with optimized physicochemical profile and large-scale production in Escherichia coli.

Structural engineering of the recombinant thrombolytic drug, Reteplase, and its cost-effective production are important goals in the pharmaceutical industry. In this study, a single-point mutant of the protein was rationally designed and evaluated in terms of physicochemical characteristics, enzymatic activity, as well as large-scale production settings. An accurate homology model of Reteplase was used as the input to appropriate tools to identify the aggregation-prone sites, while considering the structural stability. Selected variants underwent extensive molecular dynamic simulations (total 540 ns) to assess their solvation profile and their thermal stability. The Reteplase-fibrin interaction was investigated by docking. The best variant was expressed in E. coli, and Box-Behnken design was used through response surface methodology to optimize its expression conditions. M72R mutant demonstrated appropriate stability, enhanced enzymatic activity (p < 0.05), and strengthened binding to fibrin, compared to the wild type. The optimal conditions for the variant's production in a bioreactor was shown to be 37 ºC, induction with 0.5 mM IPTG, for 2 h of incubation. Under these conditions, the final amount of the produced enzyme was increased by about 23 mg/L compared to the wild type, with an increase in the enzymatic activity by about 2 IU/mL. This study thus offered a new Reteplase variant with nearly all favorable properties, except solubility. The impact of temperature and incubation time on its large-scale production were underlined as well.

Combinatorial in silico and in vivo evaluation of immune response elicitation by the affibody ZHER2.

Due to the high affinity for binding to target molecules and also other unique attributes, affibodies have a great potential to be used in immunotherapeutic and diagnostic approaches. However, the possibility of undesirable immune response is still a great concern. In the current study, we investigated the possible antigenicity, allergenicity and cytotoxicity of the HER2-targeting affibody ZHER2. The binding affinity of potential epitopes of the affibody to murine major histocompatibility complex (MHC) molecules was investigated by immunoinformatics tools and docking approaches. The possible interaction of ZHER2 with human leukocyte antigens HLA-DP, HLA-DM, HLA-DQ and HLA-DR was also studied by protein-protein docking. Additionally, the synthesized affibody gene was expressed and the protein was purified for boosted immunization of Balb/c mice. Induced secretion of IFN-γ, IL-2, IL-4 and IL-10, and total serum IgG were assessed in the immunized mice. Furthermore, MTT cell viability test was performed to evaluate the cytotoxicity of ZHER2 in splenocytes of the treated mice. In silico analyses showed the possible induction of the immune response by ZHER2. While the affibody could elicit the secretion of cellular immune cytokines, it could not induce a significant humoral response in the treated mice and did not show any cytotoxic effects on the exposed splenocytes. These findings explain the practicability of ZHER2 for therapeutic and in vivo diagnostic usages, though its ubiquitous application may need more studies.

Dissolving microneedle-assisted long-acting Liraglutide delivery to control type 2 diabetes and obesity.

Integrating nanoparticles (NPs) as a smart and targeted tool for drug delivery with dissolving microneedle (DMN) patch, the non-invasive device for drug delivery, is a promising for future therapeutic delivery applications. Liraglutide (Lira) encapsulation in poly (lactic-co-glycolic acid) (PLGA) NPs provides a sustained release of Lira to 15 days in a biphasic profile which 80% of released content happens in the first 8 days. Embedding such sustained release NPs in the DMN comprising poly vinyl pyrrolidone (PVP) 50% w/v, eliminates the need for Lira subcutaneous injection. Additionally, NPs containing DMN enhance mechanical strength of needles to 5.31 N compared to DMN with pure Lira content which was 4.32 N. The flexible backing layer of the DMN was obtained via blending of PVP and poly vinyl alcohol (PVA) in 10% w/v. Circular dichroism (CD) analysis showed that Lira encapsulated in NPs maintained its native secondary structure even after solidification in DMN. In this study, the capacity of 2 kinds of 500 µm and 1000 µm needles to deliver the desired dose of drug was obtained based on experimental and mathematical methods.

3D structure prediction, dynamic investigation and rational construction of an epitope-masked thermostable bovine hyaluronidase.

Hyaluronidase (HAase) from bovine testes (BTH) has long been used in broad pharmaceutical areas, while it is associated with drawbacks in aspects of solubility, immunogenicity and pharmacokinetics. These issues can be addressed by gaining structural insights and designing rational modifications to the enzyme structure, as proposed in this study. A 3D structural model was built for HAase and underwent 40 ns of molecular dynamic simulation to examine its thermostability under normal, melting, and extreme conditions. The enzyme activity of BTH was measured against temperature and pH by kinetic assays. The interaction of bovine HAase with HA and chondroitin was defined by molecular docking. Furthermore, immunogenic properties of the enzyme were explored by immunoinformatics. Thermal effects on bovine HAase structural model and the HAase interactions with its substrates were described. We identified some B- and T-cell epitopes and showed that the protein could be recognized by human immune receptor molecules. Epitope masking by adding polyethylene glycol (PEG) to amine groups of residues presenting on the surface of the protein structure was adopted as a surface modification to enhance pharmacological properties of BTH. Assays showed that PEGylated BTH had higher thermostability and similar activity compared to the native enzyme.

New quinoxalin-1,3,4-oxadiazole derivatives: Synthesis, characterization, in vitro biological evaluations, and molecular modeling studies.

A new series of quinoxalin-1,3,4-oxadiazole (10a-l) derivatives was synthesized and evaluated against some metabolic enzymes including human carbonic anhydrase (hCA) isoenzymes I and II (carbonic anhydrases I and II), cholinesterase (acetylcholinesterase and butyrylcholinesterase), and α-glucosidase. Obtained data revealed that all the synthesized compounds were more potent as compared with the used standard inhibitors against studied target enzymes. Among the synthesized compounds, 4-fluoro derivative (10f) against hCA I, 4-chloro derivative (10i) against hCA II, 3-fluoro derivative (10e) against acetylcholinesterase and butyrylcholinesterase, and 3-bromo derivative (10k) against α-glucosidase were the most potent compounds with inhibitory activity around 1.8- to 7.37-fold better than standard inhibitors. Furthermore, docking studies of these compounds were performed at the active site of their target enzymes.

Individuals' Intention to Engage in Outpatient Cardiac Rehabilitation Programs: Prediction Based on an Enhanced Model.

Motivation is an important factor in encouraging individuals to attend rehabilitation and underpins many approaches to engagement. The aims of this study were to develop an accurate model able to predict individual intention to engage in outpatient cardiac rehabilitation (CR) programs based on the first stage of the Model of Therapeutic Engagement integrated into a socio-environmental context. The cross-sectional study in the cardiology ward of an Australian hospital included a total of 217 individuals referred to outpatient CR. Through an ordinal logistic regression, the effect of random forest (RF)-selected profile features on individual intention to engage in outpatient CR was explored. The RF based on the conditional inference trees predicted the intention to engage in outpatient CR with high accuracy. The findings highlighted the significant roles of individuals' 'willingness to consider the treatment', 'perceived self-efficacy' and 'perceived need for rehabilitation' in their intention, while the involvement of 'barriers to engagement' and 'demographic and medical factors' was not evident.

Terminal Peptide Extensions Augment the Retinal IMPDH1 Catalytic Activity and Attenuate the ATP-induced Fibrillation Events.

Defects in inosine monophosphate dehydrogenase-1 (IMPDH1) lead to insufficient biosyntheses of purine nucleotides. In eyes, these defects are believed to cause retinitis pigmentosa (RP). Major retinal isoforms of IMPDH1 are structurally distinct from those in other tissues, by bearing terminal extensions. Using recombinant mouse IMPDH1 (mH1), we evaluated the kinetics and oligomerization states of the retinal isoforms. Moreover, we adopted molecular simulation tools to study the possible effect of terminal tails on the function of major enzyme isoforms with the aim to find structural evidence in favor of contradictory observations on retinal IMPDH1 function. Our findings indicated higher catalytic activity for the major mouse retinal isoform (mH1603) along with lower fibrillation capacity under the influence of ATP. However, higher mass oligomerization products were formed by the mH1 (603) isoform in the presence of the enzyme inhibitors such as GTP and/or MPA. Collectively, our findings demonstrate that the structural differences between the retinal isoforms have led to functional variations possibly to justify the retinal cells' requirements.

Quinazolinone-dihydropyrano[3,2-b]pyran hybrids as new α-glucosidase inhibitors: Design, synthesis, enzymatic inhibition, docking study and prediction of pharmacokinetic.

A series of new quinazolinone-dihydropyrano[3,2-b]pyran derivatives 10A-L were synthesized by simple chemical reactions and were investigated for inhibitory activities against α-glucosidase and α-amylase. New synthesized compounds showed high α-glucosidase inhibition effects in comparison to the standard drug acarbose and were inactive against α-amylase. Among them, the most potent compound was compound 10L (IC50 value = 40.1 ± 0.6 µM) with inhibitory activity around 18.75-fold more than acarboase (IC50 value = 750.0 ± 12.5 µM). This compound was a competitive inhibitor into α-glucosidase. Our obtained experimental results were confirmed by docking studies. Furthermore, the cytotoxicity of the most potent compounds 10L, 10G, and 10N against normal fibroblast cells and in silico druglikeness, ADME, and toxicity prediction of these compounds were also evaluated.