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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14

Cellular mRNA triggers structural transformation of Ebola virus matrix protein VP40 to its essential regulatory form

The Ebola virus matrix protein VP40 forms distinct structures linked to distinct functions in the virus life cycle. Dimeric VP40 is a structural protein associated with virus assembly, while octameric, ring-shaped VP40 is associated with transcriptional control. In this study, we show that suitable nucleic acid is sufficient to trigger a dynamic transformation of VP40 dimer into the octameric ring. Deep sequencing reveals a binding preference of the VP40 ring for the 3' untranslated region of cellular mRNA and a guanine- and adenine-rich binding motif. Complementary analyses of the nucleic-acid-induced VP40 ring by native mass spectrometry, electron microscopy, and X-ray crystal structures at 1.8 and 1.4 Å resolution reveal the stoichiometry of RNA binding, as well as an interface involving a key guanine nucleotide. The host factor-induced structural transformation of protein structure in response to specific RNA triggers in the Ebola virus life cycle presents unique opportunities for therapeutic inhibition.

3′ UTR↗

Changes in Peripheral Blood Regulatory T Cells and IL-6 and IL-10 Levels Predict Response of Pediatric Medulloblastoma and Germ Cell Tumors With Residual or Disseminated Disease to Craniospinal Irradiation

Radiation therapy (RT) modulates immune cells and cytokines, resulting in both clinically beneficial and detrimental effects. The changes in peripheral blood T lymphocyte subsets and cytokines during RT for pediatric brain tumors and the association of these changes with therapeutic outcomes have not been well described.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

A review of regulatory standard test methods for residential wood heaters and recommendations for their advancement

In many regions, residential wood heaters are a leading source of harmful air pollution but only satisfy a small portion of local heating demands. In response, standardized laboratory test methods have been developed to characterize and limit wood heater emissions. While these test methods are a key tool for advancing both wood heater technology and environmental regulations, many of the experimental procedures are outdated and provide few actionable insights for improving heater performance. Furthermore, these test methods vary widely around the world and may not adequately capture the performance of wood heaters operating in residences. This study presents a comprehensive review of standardized wood heater test methods to identify fundamental experimental objectives and regulated performance metrics. Using the results of this review, recommendations are provided to make the test methods more accessible and representative of residential performance, while generating actionable data to motivate heater design improvements. This study elucidates the current state of standard test methods, and the developments needed to advance clean wood heater technologies and public policies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Lipo-chitooligosaccharides as regulatory signals of fungal growth and development

Lipo-chitooligosaccharides (LCOs) are signaling molecules produced by rhizobial bacteria that trigger the nodulation process in legumes, and by some fungi that also establish symbiotic relationships with plants, notably the arbuscular and ecto mycorrhizal fungi. Here, we show that many other fungi also produce LCOs. We tested 59 species representing most fungal phyla, and found that 53 species produce LCOs that can be detected by functional assays and/or by mass spectroscopy. LCO treatment affects spore germination, branching of hyphae, pseudohyphal growth, and transcription in non-symbiotic fungi from the Ascomycete and Basidiomycete phyla. Our findings suggest that LCO production is common among fungi, and LCOs may function as signals regulating fungal growth and development.

59 BASIC BIOLOGICAL SCIENCES↗

Crystal structures reveal catalytic and regulatory mechanisms of the dual-specificity ubiquitin/FAT10 E1 enzyme Uba6

The E1 enzyme Uba6 initiates signal transduction by activating ubiquitin and the ubiquitin-like protein FAT10 in a two-step process involving sequential catalysis of adenylation and thioester bond formation. To gain mechanistic insights into these processes, we determined the crystal structure of a human Uba6/ubiquitin complex. Two distinct architectures of the complex are observed: one in which Uba6 adopts an open conformation with the active site configured for catalysis of adenylation, and a second drastically different closed conformation in which the adenylation active site is disassembled and reconfigured for catalysis of thioester bond formation. Surprisingly, an inositol hexakisphosphate (InsP6) molecule binds to a previously unidentified allosteric site on Uba6. Our structural, biochemical, and biophysical data indicate that InsP6 allosterically inhibits Uba6 activity by altering interconversion of the open and closed conformations of Uba6 while also enhancing its stability. In addition to revealing the molecular mechanisms of catalysis by Uba6 and allosteric regulation of its activities, our structures provide a framework for developing Uba6-specific inhibitors and raise the possibility of allosteric regulation of other E1s by naturally occurring cellular metabolites.

59 BASIC BIOLOGICAL SCIENCES↗