Antineoplastic effect of compounds C14 and P8 on TNBC and radioresistant TNBC cells by stabilizing the K-Ras4B/PDE6δ complex.

Introduction: Breast cancer (BC) is the leading cause of cancer-related deaths among women, with triple-negative breast cancer (TNBC) representing one of the most aggressive and treatment-resistant subtypes. In this study, we aimed to evaluate the antitumor potential of C14 and P8 molecules in both TNBC and radioresistant TNBC cells. These compounds were chosen for their ability to stabilize the complex formed by the overactivated form of K-Ras4B and its membrane transporter (PDE6δ).

p.D446E Variant as a Risk Allele for Arrhythmogenic Phenotypes: Electrophysiological Characterization Reveals a Complex Phenotype Affecting the Slow Delayed Rectifier Potassium Current (IKs) Voltage Dependence by Causing a Hyperpolarizing Shift and a Lack of Response to Protein Kinase A Activation.

Genetic testing is crucial in inherited arrhythmogenic channelopathies; however, the clinical interpretation of genetic variants remains challenging. Incomplete penetrance, oligogenic, polygenic or multifactorial forms of channelopathies further complicate variant interpretation. We identified the /p.

Synergistic effect of antagonists to KRas4B/PDE6 molecular complex in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis among all human cancers as it is highly resistant to chemotherapy. K-Ras mutations usually trigger the development and progression of PDAC. We hypothesized that compounds stabilizing the KRas4B/PDE6δ complex could serve as PDAC treatments.

Synergistic effect of compounds directed to triosephosphate isomerase, a combination to develop drug against trichomoniasis.

The development of new drugs is continuous in the world; currently, saving resources (both economic ones and time) and preventing secondary effects have become a necessity for drug developers. Trichomoniasis is the most common nonviral sexually transmitted infection affecting more than 270 million people around the world. In our research group, we focussed on developing a selective and more effective drug against Trichomonas vaginalis, and we previously reported on a compound, called A4, which had a trichomonacidal effect.

Hen lysozyme fibrillogenesis, molten globule intermediate and effect of copper salts.

The amyloid fibres have been related to many diseases. The molten globule intermediate has been proposed to form part of the folding pathway of many proteins. In the present study, we investigated the mechanism of amyloid-fibres formation of hen egg-white lysozyme (HEWL) incubated in a potassium phosphate buffer, pH 11.

Triosephosphate isomerase as a therapeutic target against trichomoniasis.

Trichomoniasis is the most common non-viral sexually transmitted infection, caused by the protozoan parasite Trichomonas vaginalis, affecting millions of people worldwide. The main treatment against trichomoniasis is metronidazole and other nitroimidazole derivatives, but up to twenty percent of clinical cases of trichomoniasis are resistant to these drugs. In this study, we used high-performance virtual screening to search for molecules that specifically bind to the protein, triosephosphate isomerase from T.

Enthalpically-driven ligand recognition and cavity solvation of bovine odorant binding protein.

Lipocalins are a widely distributed family of extracellular proteins typically involved in the transport of small hydrophobic molecules. To gain new insights into the molecular basis that governs ligand recognition by this ancient protein family, the binding properties of the domain-swapped dimer bovine odorant binding protein (bOBP) and its monomeric mutant bOBP were characterized using calorimetric techniques and molecular dynamics simulations. Thermal unfolding profiles revealed that the isolated bOBP subunits behave as a cooperative folding unit.

Laccases: structure, function, and potential application in water bioremediation.

The global rise in urbanization and industrial activity has led to the production and incorporation of foreign contaminant molecules into ecosystems, distorting them and impacting human and animal health. Physical, chemical, and biological strategies have been adopted to eliminate these contaminants from water bodies under anthropogenic stress. Biotechnological processes involving microorganisms and enzymes have been used for this purpose; specifically, laccases, which are broad spectrum biocatalysts, have been used to degrade several compounds, such as those that can be found in the effluents from industries and hospitals.

KRas4B-PDE6δ complex stabilization by small molecules obtained by virtual screening affects Ras signaling in pancreatic cancer.

Background: The GTPase KRas4B has been utilized as a principal target in the development of anticancer drugs. PDE6δ transports KRas4B to the plasma membrane, where it is released to activate various signaling pathways required for the initiation and maintenance of cancer. Therefore, identifying new small molecules that prevent activation of this GTPase by stabilizing the KRas4B-PDE6δ molecular complex is a practical strategy to fight against cancer.

The small organic molecule C19 binds and strengthens the KRAS4b-PDEδ complex and inhibits growth of colorectal cancer cells in vitro and in vivo.

Background: Colorectal cancer is the third most common cancer worldwide; and in 40% of all cases, KRAS4b-activating mutations occur. KRAS4b is transported by phosphodiesterase-6δ (PDEδ) to the plasma membrane, where it gets activated. PDEδ downregulation prevents redistribution and activation of KRAS4b.

Compound heterozygous KCNQ1 mutations (A300T/P535T) in a child with sudden unexplained death: Insights into possible molecular mechanisms based on protein modeling.

Sudden death in a child is a devastating event with important medical implications for surviving relatives. Because it may be the first manifestation of unknown inherited cardiac disease, molecular autopsy can be helpful to determine the cause of death and identify at risk family members. The aim of the study was to perform a molecular autopsy in a seven year-old girl with sudden unexplained death, to find evidence supporting the possible pathogenicity of mutations identified in inherited cardiac disease genes, and to clinically and genetically assess first-degree relatives.

A new nucleocytoplasmic RhoGAP protein contributes to control the pathogenicity of Entamoeba histolytica by regulating EhRacC and EhRacD activity.

Small GTPases are signalling molecules that regulate important cellular processes. GTPases are deactivated by GTPase-activating proteins (GAPs). While human GAPs have been intensively studied, no GAP has yet been characterized in Entamoeba histolytica.

Multinucleation and Polykaryon Formation is Promoted by the EhPC4 Transcription Factor in Entamoeba histolytica.

Entamoeba histolytica is the intestinal parasite responsible for human amoebiasis that is a leading cause of death in developing countries. In this protozoan, heterogeneity in DNA content, polyploidy and genome plasticity have been associated to alterations in mechanisms controlling DNA replication and cell division. Studying the function of the transcription factor EhPC4, we unexpectedly found that it is functionally related to DNA replication, and multinucleation.

Inhibition and biochemical characterization of methicillin-resistant Staphylococcus aureus shikimate dehydrogenase: an in silico and kinetic study.

Methicillin-resistant Staphylococcus auerus (MRSA) strains are having a major impact worldwide, and due to their resistance to all β-lactams, an urgent need for new drugs is emerging. In this regard, the shikimate pathway is considered to be one of the metabolic features of bacteria and is absent in humans. Therefore enzymes involved in this route, such as shikimate dehydrogenase (SDH), are considered excellent targets for discovery of novel antibacterial drugs.

Discovery of Entamoeba histolytica hexokinase 1 inhibitors through homology modeling and virtual screening.

Entamoeba histolytica, the parasite which causes amebiasis is responsible for 110,000 deaths a year. Entamoeba histolytica depends on glycolysis to obtain ATP for cellular work. According to metabolic flux studies, hexokinase exerts the highest flux control of this metabolic pathway; therefore, it is an excellent target in the search of new antiamebic drugs.

The α-helical regions of KERP1 are important in Entamoeba histolytica adherence to human cells.

The lysine and glutamic acid rich protein KERP1 is a unique surface adhesion factor associated with virulence in the human pathogen Entamoeba histolytica. Both the function and structure of this protein remain unknown to this date. Here, we used circular dichroism, analytical ultracentrifugation and bioinformatics modeling to characterize the structure of KERP1.

Consequences of two naturally occurring missense mutations in the structure and function of Bruton agammaglobulinemia tyrosine kinase.

Bruton agammaglobulinemia tyrosine kinase (BTK) is a key protein in the B-cell receptor (BCR) signaling pathway and plays an essential role in the differentiation of B lymphocytes. X-linked agammaglobulinemia (XLA) is a primary humoral immunodeficiency caused by mutations in the gene encoding BTK. Previously, we identified two novel variations, L111P and E605G, in BTK; these are localized within the pleckstrin homology and Src homology 1 domains, respectively.

Conformational dynamics of L-lysine, L-arginine, L-ornithine binding protein reveals ligand-dependent plasticity.

The molecular basis of multiple ligand binding affinity for amino acids in periplasmic binding proteins (PBPs) and in the homologous domain for class C G-protein coupled receptors is an unsolved question. Here, using unrestrained molecular dynamic simulations, we studied the ligand binding mechanism present in the L-lysine, L-arginine, L-ornithine binding protein. We developed an analysis based on dihedral angles for the description of the conformational changes upon ligand binding.

Metastability of papain and the molecular mechanism for its sequential acid-denaturation.

Acid unfolding of non-inhibited papain at pH 2 was studied by means of spectroscopic and electrophoresis techniques as well as activity assays. We found a molten globule like species (A state) similar to that previously reported for bromelain and S-carboxy-methyl-papain. We demonstrated that this A state is not thermodynamically stable but a metastable conformer which decays into an unfolded conformation in a few hours.

Integrative computational protocol for the discovery of inhibitors of the Helicobacter pylori nickel response regulator (NikR).

In order to identify novel inhibitors of the Helicobacter pylori nickel response regulator (HpNikR) an integrative protocol was performed for half a million compounds retrieved from the ZINC database. We firstly implement a structure-based virtual screening to build a library of potential inhibitors against the HpNikR using a docking analysis (AutoDock Vina). The library was then used to perform a hierarchical clustering of docking poses, based on protein-contact footprints calculation from the multiple conformations given by the AutoDock Vina software, and the drug-protein interaction analyses to identify and remove potential promiscuous compounds likely interacting with human proteins, hence causing drug side effects.

Design of thermostable beta-propeller phytases with activity over a broad range of pHs and their overproduction by Pichia pastoris.

Thermostable phytases, which are active over broad pH ranges, may be useful as feed additives, since they can resist the temperatures used in the feed-pelleting process. We designed new beta-propeller phytases, using a structure-guided consensus approach, from a set of amino acid sequences from Bacillus phytases and engineered Pichia pastoris strains to overproduce the enzymes. The recombinant phytases were N-glycosylated, had the correct amino-terminal sequence, showed activity over a pH range of 2.

A plasmid encoding parts of the dengue virus E and NS1 proteins induces an immune response in a mouse model.

A DENV-2 plasmid named pEII*EIII/NS1*,containing sequences encoding portions of the envelope protein that are potentially involved in the induction of neutralizing antibodies and a portion of the NS1 sequence that is involved in protection, is reported in this work. The synthesized subunit protein was recognized by human sera from infected patients and had the predicted size. The immunogenicity of this construct was evaluated using a mouse model in a prime-boost vaccination approach.

Selective inactivation of triosephosphate isomerase from Trypanosoma cruzi by brevifolin carboxylate derivatives isolated from Geranium bellum Rose.

In the search of molecules that can serve as leads in the design of a new drug for the treatment of Chagas' disease, we found that some brevifolin carboxylate derivatives isolated from Geranium bellum Rose, inactivate triosephosphate isomerase from Trypanosoma cruzi (TcTIM) in a species-specific manner. After spectroscopic characterization, these compounds were identified as methylbrevifolin carboxylate (1), ethylbrevifolin carboxylate (2), butylbrevifolin carboxylate (3) and the methylated derivate methyl tri-O-methylbrevifolin carboxylate (4). The concentrations required to inactivate fifty percent the activity of TcTIM were 6.

Engineering and directed evolution of a Ca2+ binding site A-deficient AprE mutant reveal an essential contribution of the loop Leu75-Leu82 to enzyme activity.

An aprE mutant from B. subtilis 168 lacking the connecting loop Leu(75)-Leu(82) which is predicted to encode a Ca(2+) binding site was constructed. Expression of the mutant gene (aprEDeltaLeu(75)-Leu(82)) produced B.