Computational Insights into the Interaction of the Conserved Cysteine-Noose Domain of the Human Respiratory Syncytial Virus G Protein with the Canonical Fractalkine Binding site of Transmembrane Receptor CX3CR1 Isoforms.

The human Respiratory Syncytial Virus (hRSV) stands as one of the most common causes of acute respiratory diseases. The infectivity of this virus is intricately linked to its membrane proteins, notably the attachment glycoprotein (G protein). The latter plays a key role in facilitating the attachment of hRSV to respiratory tract epithelial cells, thereby initiating the infection process.

Interaction between diterpene icetexanes and old yellow enzymes of Leishmania braziliensis and Trypanosoma cruzi.

Old Yellow Enzymes (OYEs) are flavin-dependent redox enzymes that promote the asymmetric reduction of activated alkenes. Due to the high importance of flavoenzymes in the metabolism of organisms, the interaction between OYEs from the parasites Trypanosoma cruzi and Leishmania braziliensis and three diterpene icetexanes (brussonol and two analogs), were evaluated in the present study, and differences in the binding mechanism and inhibition capacity of these molecules were examined. Although the aforementioned compounds showed poor and negligible activities against T.

Antimicrobial peptides grafted onto the surface of N-acetylcysteine-chitosan nanoparticles can revitalize drugs against clinical isolates of Mycobacterium tuberculosis.

Tuberculosis is caused by Mycobacterium tuberculosis (MTB) and is the leading cause of death from infectious diseases in the World. The search for new antituberculosis drugs is a high priority, since several drug-resistant TB-strains have emerged. Many nanotechnology strategies are being explored to repurpose or revive drugs.

NMR Relaxation Dispersion Experiments to Study Phosphopeptide Recognition by SH2 Domains: The Grb2-SH2-Phosphopeptide Encounter Complex.

Protein interactions are at the essence of life. Proteins evolved not to have stable structures, but rather to be specialized in participating in a network of interactions. Every interaction involving proteins comprises the formation of an encounter complex, which may have two outcomes: (i) the dissociation or (ii) the formation of the final specific complex.

The influence of pH on the structure and stability of the Grb2 dimer reveals changes in the inter-domain and molecular interaction: Could it be a modulation mechanism?

Cancer cells present an increased replicative potential as a hallmark. The increased replication leads to a higher intracellular pH. Grb2, an adapter protein, is mainly involved in several types of cancers due to its role in signaling pathways responsible for cell growth and proliferation.

The dynamics of free and phosphopeptide-bound Grb2-SH2 reveals two dynamically independent subdomains and an encounter complex with fuzzy interactions.

The growth factor receptor-bound protein 2 (Grb2) is a key factor in the regulation of cell survival, proliferation, differentiation, and metabolism. In its structure, the central Src homology 2 (SH2) domain is flanked by two Src homology 3 (SH3). SH2 is the most important domain in the recognition of phosphotyrosines.

Grb2 dimer interacts with Coumarin through SH2 domains: A combined experimental and molecular modeling study.

Grb2 is an important regulator of normal vs. oncogenic cell signaling transduction. It plays a pivotal role on kinase-mediated signaling transduction by linking Receptor Tyrosine kinases to Ras/MAPK pathway which is known to bring oncogenic outcome.

The GRASP domain in golgi reassembly and stacking proteins: differences and similarities between lower and higher Eukaryotes.

The Golgi complex is part of the endomembrane system and is responsible for receiving transport cargos from the endoplasmic reticulum and for sorting and targeting them to their final destination. To perform its function in higher eukaryotic cells, the Golgi needs to be correctly assembled as a flattened membrane sandwich kept together by a protein matrix. The precise mechanism controlling the Golgi cisternae assembly is not yet known, but it is widely accepted that the Golgi Reassembly and Stacking Protein (GRASP) is a main component of the Golgi protein matrix.

NMR assignment of free H, N and C-Grb2-SH2 domain.

Growth factor receptor-bound protein 2 (Grb2) is an adaptor protein composed of three domains, an N-terminal SH3 (nSH3), SH2 and a C-terminal SH3 (cSH3) domains. This multi-domain protein has been reported to be a key factor in many signaling pathways related to controlling cell survival, differentiation, and growth. The Grb2-SH2 domain has been a focus for the study of the interaction with peptides and small molecules to act as inhibitors in uncontrolled cell growth, and consequently inhibit tumor proliferation.

Thermodynamic analysis of interactions of the Hsp90 with adenosine nucleotides: A comparative perspective.

Hsp90s are key proteins in cellular homeostasis since they interact with many client proteins. Several studies indicated that Hsp90s are potential targets for treating diseases, such as cancer or malaria. It has been shown that Hsp90s from different organisms have peculiarities despite their high sequence identity.

H-NS uses an autoinhibitory conformational switch for environment-controlled gene silencing.

As an environment-dependent pleiotropic gene regulator in Gram-negative bacteria, the H-NS protein is crucial for adaptation and toxicity control of human pathogens such as Salmonella, Vibrio cholerae or enterohaemorrhagic Escherichia coli. Changes in temperature affect the capacity of H-NS to form multimers that condense DNA and restrict gene expression. However, the molecular mechanism through which H-NS senses temperature and other physiochemical parameters remains unclear and controversial.

Binding investigation between M2-1protein from hRSV and acetylated quercetin derivatives: H NMR, fluorescence spectroscopy, and molecular docking.

The human Respiratory Syncytial Virus (hRSV) is the main responsible for occurrences of respiratory diseases as pneumonia and bronchiolitis in children and elderly. M2-1 protein from hRSV is an important antitermination factor for transcription process that prevents the premature dissociation of the polymerase complex, making it a potential target for developing of inhibitors of the viral replication. The present study reports the interaction of the M2-1 tetramer with pera (Q1) and tetracetylated (Q2) quercetin derivatives, which were synthesized with the objective of generating stronger bioactive compounds against oxidation process.

New structural insights into Golgi Reassembly and Stacking Protein (GRASP) in solution.

Among all proteins localized in the Golgi apparatus, a two-PDZ (PSD95/DlgA/Zo-1) domain protein plays an important role in the assembly of the cisternae. This Golgi Reassembly and Stacking Protein (GRASP) has puzzled researchers due to its large array of functions and relevance in Golgi functionality. We report here a biochemical and biophysical study of the GRASP55/65 homologue in Cryptococcus neoformans (CnGRASP).

Experimental evidence and molecular modeling of the interaction between hRSV-NS1 and quercetin.

Human Respiratory Syncytial Virus is one of the major causes of acute respiratory infections in children, causing bronchiolitis and pneumonia. Non-Structural Protein 1 (NS1) is involved in immune system evasion, a process that contributes to the success of hRSV replication. This protein can act by inhibiting or neutralizing several steps of interferon pathway, as well as by silencing the hRSV ribonucleoproteic complex.

Competition between Grb2 and Plcγ1 for FGFR2 regulates basal phospholipase activity and invasion.

FGFR2-expressing human cancer cells with low concentrations of the adaptor protein Grb2 show high prevalence for metastatic outcome. In nonstimulated cells, the SH3 domain (and not the SH2 domains) of Plcγ1 directly competes for a binding site at the very C terminus of FGFR2 with the C-terminal SH3 domain of Grb2. Reduction of Grb2 concentration permits Plcγ1 access to the receptor.

Comparison of resazurin microtiter assay performance and BACTEC MGIT 960 in the susceptibility testing of Brazilian clinical isolates of Mycobacterium tuberculosis to four first-line drugs.

We assessed the performance of REMA in comparison with BACTEC MGIT 960 in the susceptibility testing of 80 Mycobacterium tuberculosis clinical isolates from Clemente Ferreira Institute against four drugs. REMA proved to be a rapid and accurate method, providing excellent correlation with BACTEC MGIT 960, with the exception of results for the ethambutol drug.

Interaction with Shc prevents aberrant Erk activation in the absence of extracellular stimuli.

Control mechanisms that prevent aberrant signaling are necessary to maintain cellular homeostasis. We describe a new mechanism by which the adaptor protein Shc directly binds the MAP kinase Erk, thus preventing its activation in the absence of extracellular stimuli. The Shc-Erk complex restricts Erk nuclear translocation, restraining Erk-dependent transcription of genes, including those responsible for oncogenic growth.

JC polyomavirus infection in candidates for kidney transplantation living in the Brazilian Amazon region.

This study evaluated the relative occurrences of BK virus (BKV) and JC virus (JCV) infections in patients with chronic kidney disease (CKD). Urine samples were analysed from CKD patients and from 99 patients without CKD as a control. A total of 100 urine samples were analysed from the experimental (CKD patients) group and 99 from the control group.

Grb2 controls phosphorylation of FGFR2 by inhibiting receptor kinase and Shp2 phosphatase activity.

Constitutive receptor tyrosine kinase phosphorylation requires regulation of kinase and phosphatase activity to prevent aberrant signal transduction. A dynamic mechanism is described here in which the adaptor protein, growth factor receptor-bound protein 2 (Grb2), controls fibroblast growth factor receptor 2 (FGFR2) signaling by regulating receptor kinase and SH2 domain-containing protein tyrosine phosphatase 2 (Shp2) phosphatase activity in the absence of extracellular stimulation. FGFR2 cycles between its kinase-active, partially phosphorylated, nonsignaling state and its Shp2-dephosphorylated state.

Microscale thermophoresis quantifies biomolecular interactions under previously challenging conditions.

Microscale thermophoresis (MST) allows for quantitative analysis of protein interactions in free solution and with low sample consumption. The technique is based on thermophoresis, the directed motion of molecules in temperature gradients. Thermophoresis is highly sensitive to all types of binding-induced changes of molecular properties, be it in size, charge, hydration shell or conformation.

Inhibition of basal FGF receptor signaling by dimeric Grb2.

Receptor tyrosine kinase activity is known to occur in the absence of extracellular stimuli. Importantly, this "background" level of receptor phosphorylation is insufficient to effect a downstream response, suggesting that strict controls are present and prohibit full activation. Here a mechanism is described in which control of FGFR2 activation is provided by the adaptor protein Grb2.

Drug resistance in Mycobacterium tuberculosis clinical isolates from Brazil: phenotypic and genotypic methods.

We determined the susceptibility profile of 80 Mycobacterium tuberculosis (MTB) clinical isolates from Brazil against isoniazid (INH) and rifampicin (RIF) drugs by two phenotypic methods (Resazurin Microtiter Assay - REMA and BACTEC™ MGIT™ Mycobacterial Detection System). DNA polymorphisms were also determined by PCR-SSCP in isolates resistant to INH and RIF. BACTEC™ MGIT™ 960 detected 22 susceptible isolates to INH and RIF, 48 MDR isolates (resistant at least to INH and RIF) and nine mono-resistant isolates (eight to INH and one to RIF).

Characterization of the genetic diversity of Mycobacterium tuberculosis in São Paulo city, Brazil.

Background: Tuberculosis is a major health problem in São Paulo, Brazil, which is the most populous and one of the most cosmopolitan cities in South America. To characterize the genetic diversity of Mycobacterium tuberculosis in the population of this city, the genotyping techniques of spoligotyping and MIRU were applied to 93 isolates collected in two consecutive years from 93 different tuberculosis patients residing in São Paulo city and attending the Clemente Ferreira Institute (the reference clinic for the treatment of tuberculosis).

Findings: Spoligotyping generated 53 different spoligotype patterns.

Assessment of the quality of dna extracted by two techniques from Mycobacterium tuberculosis for fast molecular identification and genotyping.

We report a comparative study of two DNA extraction techniques, thermolysis and chemical lysis (CTAB), for molecular identification and genotyping of M. tuberculosis. Forty DNA samples were subjected to PCR and the results demonstrated that with thermolysis it is possible to obtain useful data that enables fast identification and genotyping.