https://www.sciencedirect.com/science/article/pii/S016836591830049X Abstract Loading capacity and drug leakage from vehicles during circulation in blood is a major concern when developing nanoparticle-based cell-targeted cytotoxics. To circumvent this potential issue it would be convenient the engineering of drugs as self-delivered nanoscale entities, devoid of any heterologous carriers. In this context, we have here engineered potent protein toxins, namely segments of the diphtheria toxin and the Pseudomonas aeruginosa exotoxin as self-assembling, self-delivered therapeutic materials targeted to CXCR4+ cancer stem cells. The systemic administration of both nanostructured drugs in a colorectal cancer xenograft mouse model promotes efficient and specific local destruction of targe
http://onlinelibrary.wiley.com/doi/10.1002/biot.201700388/full Abstract The preparation of biological samples for electron microscopy is material- and time-consuming because it is often based on long protocols that also may produce artifacts. Protein labeling for transmission electron microscopy (TEM) is such an example, taking several days. However, for protein-based nanotechnology, high resolution imaging techniques are unique and crucial tools for studying the spatial distribution of these molecules, either alone or as components of biomaterials. In this paper, we tested two new short methods of immunolocalization for TEM, and compared them with a standard protocol in qualitative and quantitative approaches by using four protein-based nanoparticles. We reported a significant increas...
https://www.sciencedirect.com/science/article/pii/S0969212617304033?via%3Dihub Summary Lipases and esterases constitute a group of enzymes that catalyze the hydrolysis or synthesis of ester bonds. A major biotechnological interest corresponds to thermophilic esterases, due to their intrinsic stability at high temperatures. The Pf2001 esterase from Pyrococcus furiosus reaches its optimal activity between 70°C and 80°C. The crystal structure of the Pf2001 esterase shows two different conformations: monomer and dimer. The structures reveal important rearrangements in the “cap” subdomain between monomer and dimer, by the formation of an extensive intertwined helical interface. Moreover, the dimer interface is essential for the formation of the hydrophobic channel for substrate selectivity,
Protein nanoparticles are nontoxic, tuneable cell stressors Aim: Nanoparticle–cell interactions can promote cell toxicity and stimulate particular behavioral patterns, but cell responses to protein nanomaterials have been poorly studied. Results: By repositioning oligomerization domains in a simple, modular self-assembling protein platform, we have generated closely related but distinguishable homomeric nanoparticles. Composed by building blocks with modular domains arranged in different order, they share amino acid composition. These materials, once exposed to cultured cells, are differentially internalized in absence of toxicity and trigger distinctive cell adaptive responses, monitored by the emission of tubular filopodia and enhanced drug sensitivity. Conc
Improving biomaterials imaging for nanotechnology: rapid methods for protein localization at ultrastructural level http://onlinelibrary.wiley.com/doi/10.1002/biot.201700388/full Abstract The preparation of biological samples for electron microscopy is material- and time-consuming because it is often based on long protocols that also may produce artifacts. Protein labeling for transmission electron microscopy (TEM) is such an example, taking several days. However, for protein-based nanotechnology, high resolution imaging techniques are unique and crucial tools for studying the spatial distribution of these molecules, either alone or as components of biomaterials. In this paper, we tested 2 new short methods of immunolocalization for TEM, and compared them with a standard pr...
Protein-Based Therapeutic Killing for Cancer Therapies Naroa Serna1, Laura Sánchez-García, Ugutz Unzueta, Raquel Díaz, Esther Vázquez, Ramón Mangues, Antonio Villaverde Show more https://doi.org/10.1016/j.tibtech.2017.11.007 Targeting cytotoxic drugs in oncology is essential because side toxicities limit reaching effective local doses. Functionalization of nanoscale drug vehicles has so far achieved a moderate targeting effect. The nanoscale size of drug preparations favors enhanced permeability and retention (EPR) and reduces renal filtration. Proteins are used as inert nanoscale carriers and as functional targeting agents in the form of antibodies or ligands that bind to tumor cell-surface markers. Many protein species exhibit potent cytotoxic ac
https://www.nature.com/articles/s41598-017-17259-4 Disulfide driven folding for a conditionally disordered protein Hugo Fraga, Jordi Pujols, Marcos Gil-Garcia, Alicia Roque, Ganeko Bernardo-Seisdedos, Carlo Santambrogio, Joan-Josep Bech-Serra, Francesc Canals, Pau Bernadó, Rita Grandori, Oscar Millet & Salvador Ventura Abstract Conditionally disordered proteins are either ordered or disordered depending on the environmental context. The substrates of the mitochondrial intermembrane space (IMS) oxidoreductase Mia40 are synthesized on cytosolic ribosomes and diffuse as intrinsically disordered proteins to the IMS, where they fold into their functional conformations; behaving thus as conditionally disordered proteins. It is not clear how the sequences of these polyp
Abstract Oxidatively modified forms of proteins accumulate during aging. Oxidized protein conformers might act as intermediates in the formation of amyloids in age-related disorders. However, it is not known whether this amyloidogenic conversion requires an extensive protein oxidative damage or it can be promoted just by a discrete, localized post-translational modification of certain residues. Here, we demonstrate that the irreversible oxidation of a single free Cyssuffices to severely perturb the folding energy landscape of a stable globular protein, compromise its kinetic stability, and lead to the formation of amyloids under physiological conditions. Experiments and simulations converge to indicate that this specific oxidation-promoted protein aggregation requires only local unfol