Aedes aegypti encodes an ATPase-active RUVBL1/2 complex.

RUVBL1 and RUVBL2 proteins assemble into a heterohexameric ring and are essential for DNA repair in prokaryotes and chromatin homeostasis in eukaryotes. These proteins function as potential chaperones and ATPases. While most studies on eukaryotic RUVBL1/2 proteins have focused on human and yeast orthologs, they have revealed notable differences in conformational dynamics, protein interactions, and ATPase activity between these species.

Unraveling the Nanomechanical and Vibrational Properties of the Mayaro Virus.

Mayaro virus (MAYV) is an emerging mosquito-borne viral pathogen whose infection results in arthritogenic disease. Despite ongoing research efforts, MAYV biology is largely unknown. Physical virology can assess MAYV nanoparticle metastability, assembly/disassembly, and polymorphism, allowing us to understand virion architecture and dynamics.

Extension of sticholysins N-terminal α-helix signals membrane lipids to acquire curvature for toroidal pore formation.

Sticholysin I and II (St I/II) belong to the actinoporins family; these proteins form pores in host cell membranes by binding their N-terminal segment to the membrane, leading to protein-lipid (toroidal) pores. Peptides derived from actinoporins pore-forming domains replicate their folding properties and permeabilizing effects. Despite the advances in understanding how these proteins and peptides mediate pore formation, the role of different N-terminal segments in inducing membrane curvature is still unclear.

Photobiomodulation of Na,K-ATPase in native membrane fraction and reconstituted in DPPC:DPPE-liposome.

Studies focusing on how photobiomodulation (PBM) can affect the structure and function of proteins are scarce in the literature. Few previous studies have shown that the enzymatic activity of Na,K-ATPAse (NKA) can be photo-modulated. However, the variability of sample preparation and light irradiation wavelengths have not allowed for an unequivocal conclusion about the PBM of NKA.

Atomic Force Microscopy Applied to the Study of Tauopathies.

Atomic force microscopy (AFM) is a scanning probe microscopy technique which has a physical principle, the measurement of interatomic forces between a very thin tip and the surface of a sample, allowing the obtaining of quantitative data at the nanoscale, contributing to the surface study and mechanical characterization. Due to its great versatility, AFM has been used to investigate the structural and nanomechanical properties of several inorganic and biological materials, including neurons affected by tauopathies. Tauopathies are neurodegenerative diseases featured by aggregation of phosphorylated tau protein inside neurons, leading to functional loss and progressive neurotoxicity.

Unveiling Sticholysin II and plasmid DNA interaction: Implications for developing non-viral vectors.

Non-viral gene delivery systems offer significant potential for gene therapy due to their versatility, safety, and cost advantages over viral vectors. However, their effectiveness can be hindered by the challenge of efficiently releasing the genetic cargo from endosomes to prevent degradation in lysosomes. To overcome this obstacle, functional components can be incorporated into these systems.

Unveiling the Three-Step Model for the Interaction of Imidazolium-Based Ionic Liquids on Albumin.

The effect of the ionic liquids (ILs) 1-methyl-3-tetradecylimidazolium chloride ([CMIM][Cl]), 1-dodecyl-3-methylimidazolium chloride ([CMIM][Cl]), and 1-decyl-methylimidazolium chloride ([CMIM][Cl]) on the structure of bovine serum albumin (BSA) was investigated by fluorescence spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulations. Concerning the fluorescence measurements, we observed a blue shift and a fluorescence quenching as the IL concentration increased in the solution. Such behavior was observed for all three studied imidazolium-based ILs, being larger as the number of methylene groups in the alkyl chain increased.

Small-angle scattering from flat bilayers containing correlated scattering length density inhomogeneities.

Model lipid bilayers have been widely employed as a minimal system to investigate the structural properties of biological membranes by small-angle X-ray (SAXS) and neutron scattering (SANS) techniques. These have nanometre resolution and can give information regarding membrane thickness and scattering length densities (SLDs) of polar and apolar regions. However, biological membranes are complex systems containing different lipids and protein species, in which lipid domains can be dynamically assembled and disassembled.

The Latin American Federation of Biophysical Societies (LAFeBS).

The Latin American Federation of Biophysical Societies (LAFeBS) was constituted in 2007 in Montevideo, Uruguay, as a collaborative effort among the Biophysical Societies of Argentina, Brazil, and Uruguay. This visionary collaboration foresees the future of Biophysics in Latin America. In this commentary, we will briefly review the history of LAFeBS, the remarkable path undertaken since its foundation 16 years ago, and its key initiative, the Latin American Postgraduate Program in Biophysics (POSLATAM).

Physical virology: how physics is enabling a better understanding of recent viral invaders.

Unlabelled: The world is frequently afflicted by several viral outbreaks that bring diseases and health crises. It is vital to comprehend how viral assemblies' fundamental components work to counteract them. Determining the ultrastructure and nanomechanical characteristics of viruses from a physical standpoint helps categorize their mechanical characteristics, offers insight into new treatment options, and/or shows weak spots that can clarify methods for medication targeting.

A short review on the applicability and use of cubosomes as nanocarriers.

Abstract: Cubosomes are nanostructured lipid-based particles that have gained significant attention in the field of drug delivery and nanomedicine. These unique structures consist of a three-dimensional cubic lattice formed by the self-assembly of lipid molecules. The lipids used to construct cubosomes are typically nonionic surfactants, such as monoolein, which possess both hydrophilic and hydrophobic regions, allowing them to form stable, water-dispersible nanoparticles.

Sorghum bicolor SbHSP110 has an elongated shape and is able of protecting against aggregation and replacing human HSPH1/HSP110 in refolding and disaggregation assays.

Perturbations in the native structure, often caused by stressing cellular conditions, not only impair protein function but also lead to the formation of aggregates, which can accumulate in the cell leading to harmful effects. Some organisms, such as plants, express the molecular chaperone HSP100 (homologous to HSP104 from yeast), which has the remarkable capacity to disaggregate and reactivate proteins. Recently, studies with animal cells, which lack a canonical HSP100, have identified the involvement of a distinct system composed of HSP70/HSP40 that needs the assistance of HSP110 to efficiently perform protein breakdown.

Peg-Grafted Liposomes for L-Asparaginase Encapsulation.

L-asparaginase (ASNase) is an important biological drug used to treat Acute Lymphoblastic Leukemia (ALL). It catalyzes the hydrolysis of L-asparagine (Asn) in the bloodstream and, since ALL cells cannot synthesize Asn, protein synthesis is impaired leading to apoptosis. Despite its therapeutic importance, ASNase treatment is associated to side effects, mainly hypersensitivity and immunogenicity.

Thymus vulgaris essential oil + tobramycin within nanostructured archaeolipid carriers: A new approach against Pseudomonas aeruginosa biofilms.

Background: Pseudomonas aeruginosa biofilms in the respiratory tract of patients with an excessive inflammatory context are difficult to eradicate. New medicines that simultaneously target biofilms and inflammation should be developed.

Hypothesis: Co-delivery of Thymus vulgaris essential oil (EOT) and tobramycin (TB) by nanostructured archaeolipids carriers (NAC) could support nebulization as well as improve EOT and TB antioxidant, anti-inflammatory and antibiofilm activity.

Structural, thermodynamic and functional studies of human 71 kDa heat shock cognate protein (HSPA8/hHsc70).

Human 71 kDa heat shock cognate protein (HSPA8, also known as Hsc70, Hsp70-8, Hsc71, Hsp71 or Hsp73) is a constitutively expressed chaperone that is critical for cell proteostasis. In the cytosol, HSPA8 plays a pivotal role in folding and refolding, facilitates protein trafficking across membranes and targets proteins for degradation, among other functions. Here, we report an in solution study of recombinant HSPA8 (rHSPA8) using a variety of biophysical and biochemical approaches.

Assembly principles of the human R2TP chaperone complex reveal the presence of R2T and R2P complexes.

R2TP is a highly conserved chaperone complex formed by two AAA+ ATPases, RUVBL1 and RUVBL2, that associate with PIH1D1 and RPAP3 proteins. R2TP acts in promoting macromolecular complex formation. Here, we establish the principles of R2TP assembly.

Targeting intracellular Leishmania (L.) infantum with nitazoxanide entrapped into phosphatidylserine-nanoliposomes: An experimental study.

Leishmaniasis is a parasitic neglected tropical disease and result in a broad spectrum of clinical manifestations, ranging from a single ulceration to a progressive and fatal visceral disease. Comprising a limited and highly toxic therapeutic arsenal, new treatments are urgently needed. Targeting delivery of drugs has been a promising approach for visceral leishmaniasis (VL).

Cubic-to-inverted micellar and the cubic-to-hexagonal-to-micellar transitions on phytantriol-based cubosomes induced by solvents.

Cubosomes are nanoparticles composed of a specific combination of some types of amphiphilic molecules like lipids, such as phytantriol (PHY), and a nonionic polymer, like poloxamer (F127). Cubosomes have a high hydrophobic volume (> 50%) and are good candidates for drug delivery systems. Due to their unique structure, these nanoparticles possess the ability to incorporate highly hydrophobic drugs.

Solution structure of Plasmodium falciparum Hsp90 indicates a high flexible dimer.

Hsp90 is a ubiquitous, homodimer and modular molecular chaperone. Each Hsp90 protomer has three different domains, named the N-terminal domain (NTD), middle domain (MD) and C-terminal domain (CTD). The Hsp90 molecular cycle involves ATP binding and hydrolysis, which drive conformational changes.

On the structure and function of Sorghum bicolor CHIP (carboxyl terminus of Hsc70-interacting protein): A link between chaperone and proteasome systems.

The co-chaperone CHIP (carboxy terminus of Hsc70 interacting protein) is very important for many cell activities since it regulates the ubiquitination of substrates targeted for proteasomal degradation. However, information on the structure-function relationship of CHIP from plants and how it interacts and ubiquitinates other plant chaperones is still needed. For that, the CHIP ortholog from Sorghum bicolor (SbCHIP) was identified and studied in detail.

Heat shock protein 90 kDa (Hsp90) from Aedes aegypti has an open conformation and is expressed under heat stress.

Cellular proteostasis is maintained by a system consisting of molecular chaperones, heat shock proteins (Hsps) and proteins involved with degradation. Among the proteins that play important roles in the function of this system is Hsp90, which acts as a node of this network, interacting with at least 10% of the proteome. Hsp90 is ATP-dependent, participates in critical cell events and protein maturation and interacts with large numbers of co-chaperones.

Sorafenib as an Inhibitor of RUVBL2.

RUVBL1 and RUVBL2 are highly conserved ATPases that belong to the AAA+ (ATPases Associated with various cellular Activities) superfamily and are involved in various complexes and cellular processes, several of which are closely linked to oncogenesis. The proteins were implicated in DNA damage signaling and repair, chromatin remodeling, telomerase activity, and in modulating the transcriptional activities of proto-oncogenes such as c-Myc and β-catenin. Moreover, both proteins were found to be overexpressed in several different types of cancers such as breast, lung, kidney, bladder, and leukemia.

ClpP protease activation results from the reorganization of the electrostatic interaction networks at the entrance pores.

Bacterial ClpP is a highly conserved, cylindrical, self-compartmentalizing serine protease required for maintaining cellular proteostasis. Small molecule acyldepsipeptides (ADEPs) and activators of self-compartmentalized proteases 1 (ACP1s) cause dysregulation and activation of ClpP, leading to bacterial cell death, highlighting their potential use as novel antibiotics. Structural changes in and ClpP upon binding to novel ACP1 and ADEP analogs were probed by X-ray crystallography, methyl-TROSY NMR, and small angle X-ray scattering.