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Ni-rich layered oxides as high-capacity battery cathodes suffer from degradation at high voltages. We utilize a dry surface modification method, mechanofusion (MF), to achieve enhanced battery stability. The simplicity, high yield, and flexibility make it cost-effective and highly attractive for processing at the industrial scale. The underlying mechanisms responsible for performance improvement are unveiled by a systematic study combining multiple probes, e.g., 3D nano-tomography, spectroscopic imaging, in situ synchrotron diffraction, and finite element analysis (FEA). MF affects the bulk crystallography by introducing partially disordered structure, microstrain, and local lattice variation. Furthermore, the crack initiation and propagation pattern during delithiation are regulated and the overall mechanical fracture is reduced after such surface coating. We validate that MF can alter the bulk charging pathways. Such a synergic effect between surface modification and bulk charge distribution is fundamentally important for designing next-generation battery cathode materials.

Phosphodiesterase 3A (PDE3A) is an enzyme that plays an important role in the regulation of cyclic adenosine monophosphate (cAMP)-mediated intracellular signaling in cardiac myocytes and platelets. PDE3A hydrolyzes cAMP, which results in a decrease in intracellular cAMP levels and leads to platelet activation. Whole-exome sequencing of 50 DNA samples from a healthy Korean population revealed a total of 13 single nucleotide polymorphisms including five missense variants, D12N, Y497C, H504Q, C707R, and A980V. Recombinant proteins for the five variants of PDE3A (and wild-type protein) were expressed in a FreeStyle 293 expression system with site-directed mutagenesis. The expression of the recombinant PDE3A proteins was confirmed with Western blotting. Catalytic activity of the PDE3A missense variants and wild-type enzyme was measured with a PDE-based assay. Effects of the missense variants on the inhibition of PDE3A activity by cilostazol were also investigated. All variant proteins showed reduced activity (33-53%; p < .0001) compared to the wild-type protein. In addition, PDE3A activity was inhibited by cilostazol in a dose-dependent manner and was further suppressed in the missense variants. Specifically, the PDE3A Y497C showed significantly reduced activity, consistent with the predictions of in silico analyses. The present study provides evidence that individuals carrying the PDE3A Y497C variant may have lower enzyme activity for cAMP hydrolysis, which could cause interindividual variation in cAMP-mediated physiological functions.

This paper reviews the NTIRE 2020 challenge on perceptual extreme super-resolution with focus on proposed solutions and results. The challenge task was to super-resolve an input image with a magnification factor 16 based on a set of prior examples of low and corresponding high resolution images. The goal is to obtain a network design capable to produce high resolution results with the best perceptual quality and similar to the ground truth. The track had 280 registered participants, and 19 teams submitted the final results. They gauge the state-of-the-art in single image super-resolution., Comment: CVPRW 2020

CYP4F2 is an enzyme involved in the formation of 20-hydroxyeicosatetraenoic acid (20-HETE) from arachidonic acid and metabolizes vitamin K into an inactive form. Our objectives were to identify new CYP4F2 genetic variants and to characterize the functional consequences of the conversion of arachidonic acid into 20-HETE. We used direct DNA sequencing to identify a total of 20 single-nucleotide polymorphisms (SNPs) including four coding variants, A27V, R47C, P85A, and V433M, in 50 randomly selected subjects. Of these, A27V and P85A were new. Recombinant variant proteins were prepared using an Escherichia coli expression system, purified, and quantified via CO-difference spectral analysis. The conversion of arachidonic acid to 20-HETE by the coding variants was compared to that of the wild-type protein. Wild-type CYP4F2 exhibited the highest intrinsic clearance, followed by P85A, A27V, V433M, and R47C (40-65% of the wild-type value). The locations of the mutated residues in the three-dimensional protein structure were predicted by structural modeling, and the possible effects on 20-HETE synthesis discussed. In summary, we describe the allele frequency, haplotype distribution, and linkage disequilibrium of CYP4F2 and functionally analyze the CYP4F2 coding variants. Our findings suggest that individuals having the low-activity alleles of CYP4F2 may inefficiently convert arachidonic acid into 20-HETE. This may aid in our understanding of 20-HETE-related blood pressure problems and cardiovascular diseases when genotype-phenotype association studies are performed in the future.

A tandem approach for the stereoselective allylic reduction has been developed based on a strategy combining the palladium-catalyzed S-allylation and the sulfinyl retro-ene reactions. In a one-pot process employing various allylic carbonates, sodium t-butyldimethylsilyloxymethanesulfinate (TBSOMS-Na), easily prepared from the commercially available reagent Rongalite™, serves as a potent nucleophile to engage in the Tsuji–Trost S-allylation reaction generating allylic sulfone products. Subsequently, in situ deprotection of the TBSOMS group reveals allylic sulfinic acids which undergo stereospecific reductive transposition via sulfur dioxide extrusion to provide alkene products.

This book is titled after the Cul de Sac plain in the Western Province of French Saint-Domingue where the Ferron de la Ferronnays owned a sugar plantation. Drawing on the Ferronnays’ family papers ...

The N-terminal von Willebrand domain of Ku80 supports interactions with a Ku binding motif (KBM) that has been identified in at least three other DNA repair proteins: the non-homologous end joining (NHEJ) scaffold APLF, the modulator of retrovirus infection, MRI, and the Werner syndrome protein (WRN). A second, more recently identified Ku binding motif present in XLF and several other proteins (KBMX) has also been reported to interact with this domain. The isolated Ku80 von Willebrand antigen domain (vWA) from Xenopus laevis has a sequence that is 60% identical with the human domain, is readily expressed and has been used to investigate these interactions. Structural characterization of the complexes formed with the KBM motifs in human APLF, MRI, and WRN identify a conserved binding site that is consistent with previously-reported mutational studies. In contrast with the KBM binding site, structural studies indicate that the KBMX site is occluded by a distorted helix. Fluorescence polarization and 19F NMR studies of a fluorinated XLF C-terminal peptide failed to indicate any interaction with the frog vWA. It was hypothesized that availability of this binding site is conditional, i.e., dependent on specific experimental conditions or other repair factors to make the site available for binding. Modulating the fraction of KBMX-accessible binding site mutationally demonstrated that the more open site is capable of binding the KBMXXLF motif peptide. It is suggested that the conditional nature of KBMX binding limits formation of non-productive complexes so that activation-dependent site availability can more optimally support advancing the synapsis process.

PURPOSE OF REVIEW: Allergen-antibody complexes are extremely valuable in describing the detailed molecular features of epitopes. This review summarizes insights gained from recently published co-structures and what obstacles impede the acquisition of further data. RECENT FINDINGS: Structural epitope data helped define the epitopes of two anti-Fel d 1 antibodies undergoing phase I clinical trials, providing a greater level of detail than was possible through hydrogen exchange protection studies. Separately, a human camelid-like antibody structure with lysozyme described several unique features in a long variable loop that interacted with the active site cleft of Gal d 4. Finally, a co-structure conclusively demonstrated that Phl p 7 could function as a superantigen, and that an antibody could simultaneously recognize two epitopes. These remarkable assertions would not have been possible without visualization of the complex. Only 3 new complexes have appeared in the last few years, suggesting there are major impediments to traditional production and crystallization. SUMMARY: The structural data was extremely valuable in describing epitopes. New techniques like cryo-EM may provide an alternative to crystallography.

Multidrug tolerance is largely responsible for chronic infections and caused by a small population of dormant cells called persisters. Selection for survival in the presence of antibiotics produced the first genetic link to multidrug tolerance: a mutant in the Escherichia coli hipA locus. HipA encodes a serine-protein kinase, the multidrug tolerance activity of which is neutralized by binding to the transcriptional regulator HipB and hipBA promoter. The physiological role of HipA in multidrug tolerance, however, has been unclear. Here we show that wild-type HipA contributes to persister formation and that high-persister hipA mutants cause multidrug tolerance in urinary tract infections. Perplexingly, high-persister mutations map to the N-subdomain-1 of HipA far from its active site. Structures of higher-order HipA–HipB–promoter complexes reveal HipA forms dimers in these assemblies via N-subdomain-1 interactions that occlude their active sites. High-persistence mutations, therefore, diminish HipA–HipA dimerization, thereby unleashing HipA to effect multidrug tolerance. Thus, our studies reveal the mechanistic basis of heritable, clinically relevant antibiotic tolerance. The molecular basis of multidrug tolerance in chronic urinary tract infections is mediated by mutations in the N-subdomain-1 of the Escherichia coli HipA protein kinase. The spread of multidrug tolerance among bacterial pathogens is mainly due to the existence of 'persisters', phenotypic variants that lie dormant and so are not susceptible to antibiotics that are effective only against actively growing cells. Maria Schumacher et al. show here that wild-type HipA, a serine protein kinase that inhibits protein synthesis and drives cells into dormancy, contributes to persister formation in Escherichia coli, and that hipA7 high-persister mutants are present in patients with urinary tract infections. The authors determine the structures of transcription autorepression complexes consisting of promoter DNA and HipA–HipB complexes. These structures reveal that high-persistence mutations function by interfering with HipA–HipA interactions, releasing HipA from the higher-order complex and triggering multidrug tolerance.

The nuclear protein constitutive active/androstane receptor (CAR or NR1I3) regulates several liver functions such as drug and energy metabolism and cell growth or death, which are often involved in the development of diseases such as diabetes and hepatocellular carcinoma. CAR undergoes a conversion from inactive homodimers to active heterodimers with retinoid X receptor α (RXRα), and phosphorylation of the DNA-binding domain (DBD) at Thr-38 in CAR regulates this conversion. Here, we uncovered the molecular mechanism by which this phosphorylation regulates the intramolecular interaction between CAR's DBD and ligand-binding domain (LBD), enabling the homodimer–heterodimer conversion. Phosphomimetic substitution of Thr-38 with Asp increased co-immunoprecipitation of the CAR DBD with CAR LBD in Huh-7 cells. Isothermal titration calorimetry assays also revealed that recombinant CAR DBD-T38D, but not nonphosphorylated CAR DBD, bound the CAR LBD peptide. This DBD–LBD interaction masked CAR's dimer interface, preventing CAR homodimer formation. Of note, EGF signaling weakened the interaction of CAR DBD T38D with CAR LBD, converting CAR to the homodimer form. The DBD-T38D–LBD interaction also prevented CAR from forming a heterodimer with RXRα. However, this interaction opened up a CAR surface, allowing interaction with protein phosphatase 2A. Thr-38 dephosphorylation then dissociated the DBD–LBD interaction, allowing CAR heterodimer formation with RXRα. We conclude that the intramolecular interaction of phosphorylated DBD with the LBD enables CAR to adapt a transient monomer configuration that can be converted to either the inactive homodimer or the active heterodimer.

Glucocorticoid receptor β (GRβ) is associated with glucocorticoid resistance via dominant negative regulation of GRα. To better understand how GRβ functions as a dominant negative inhibitor of GRα at a molecular level, we determined the crystal structure of the ligand binding domain of GRβ complexed with the antagonist RU-486. The structure reveals that GRβ binds RU-486 in the same ligand binding pocket as GRα, and the unique C-terminal amino acids of GRβ are mostly disordered. Binding energy analysis suggests that these C-terminal residues of GRβ do not contribute to RU-486 binding. Intriguingly, the GRβ/RU-486 complex binds corepressor peptide with affinity similar to that of a GRα/RU-486 complex, despite the lack of helix 12. Our biophysical and biochemical analyses reveal that in the presence of RU-486, GRβ is found in a conformation that favors corepressor binding, potentially antagonizing GRα function. This study thus presents an unexpected molecular mechanism by which GRβ could repress transcription.

CYP4F11, together with CYP4F2, plays an important role in the synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) from arachidonic acid. We identified 21 variants by whole exome sequencing, including 4 non-synonymous variants in Korean subjects. The proteins of the wild-type CYP4F11 and the four coding variants (C276R, D315N, D374Y, and D446N) were expressed in Escherichia coli DH5α cells and purified to give cytochrome P450-specific carbon monoxide difference spectra. Wild-type CYP4F2 was also expressed and purified to compare its activity with the CYP4F11 wild-type. Wild-type CYP4F11 exhibited the highest maximal clearance for erythromycin N-demethylase activity followed by the variants D374Y, D446N, C276R, and D315N. In particular, the CYP4F11 D315N protein showed about 50% decrease in intrinsic clearance compared to the wild type. The ability of wild-type CYP4F11 and the variants to synthesize 20-HETE from arachidonic acid was similar; the CYP4F11 D315N variant, however, showed only 68% of wild-type activity. Furthermore, the ability of CYP4F2 to synthesize 20-HETE was 1.7-fold greater than that of CYP4F11. Overall, our results suggest that the metabolism of CYP4F11 substrates may be reduced in individuals carrying the CYP4F11 D315N genetic variant and individuals carrying the common D446N CYP4F11 variant likely exhibit comparable 20-HETE synthesis as individuals expressing wild-type CYP4F11.

The increased programmability of graphics hardware allows efficient graphical processing unit (GPU) implementations of a wide range of general computations on commodity PCs. An important factor in such implementations is how to fully exploit the SIMD computing capacities offered by modern graphics processors. Linear expressions in the form of ȳ = Ax̄ + b̄, where A is a matrix, and x̄, ȳ and b̄ are vectors, constitute one of the most basic operations in many scientific computations. In this paper, we propose a SIMD code optimization technique that enables efficient shader codes to be generated for evaluating linear expressions. It is shown that performance can be improved considerably by efficiently packing arithmetic operations into four-wide SIMD instructions through reordering of the operations in linear expressions. We demonstrate that the presented technique can be used effectively for programming both vertex and pixel shaders for a variety of mathematical applications, including integrating differential equations and solving a sparse linear system of equations using iterative methods.

ABP(57) is an auxin-binding protein that possesses receptor function. In this study, a protocol for ABP(57) purification was developed on the basis of cross-reactivity shown between ABP(57) and antisera raised against bovine serum albumin, which enabled us to purify ABP(57) with a high yield and to further characterize it. ABP(57) activates plant plasma membrane H(+)-ATPase (PM H(+)-ATPase) via direct interaction. The binding of indole-3-acetic acid (IAA) to the primary binding site on ABP(57) caused a marked increase in the affinity of ABP(57) for PM H(+)-ATPase, which was accompanied by a change in ABP(57) conformation. Meanwhile, additional IAA binding to the secondary site on ABP(57) nullified the initial effect without inducing further conformational change. When ABP(57) with IAA occupying only the primary site interacted with PM H(+)-ATPase, no IAA could access the secondary site. These results suggest that IAA-induced biphasic alteration in the affinity of ABP(57) for PM H(+)-ATPase correlates with a bell-shaped dose response of the enzyme to IAA. There is also a possibility that, whereas the stimulation phase of the response is associated with a conformational change of ABP(57), the destimulation phase probably results from hindrance arising directly from the presence of IAA at the secondary site.

SummaryThe tumor-suppressive Hippo pathway controls tissue homeostasis through balancing cell proliferation and apoptosis. Activation of the kinases Mst1 and Mst2 (Mst1/2) is a key upstream event in this pathway and remains poorly understood. Mst1/2 and their critical regulators RASSFs contain Salvador/RASSF1A/Hippo (SARAH) domains that can homo- and heterodimerize. Here, we report the crystal structures of human Mst2 alone and bound to RASSF5. Mst2 undergoes activation through transautophosphorylation at its activation loop, which requires SARAH-mediated homodimerization. RASSF5 disrupts Mst2 homodimer and blocks Mst2 autoactivation. Binding of RASSF5 to already activated Mst2, however, does not inhibit its kinase activity. Thus, RASSF5 can act as an inhibitor or a potential positive regulator of Mst2, depending on whether it binds to Mst2 before or after activation-loop phosphorylation. We propose that these temporally sensitive functions of RASSFs enable the Hippo pathway to respond to and integrate diverse cellular signals.

Bacterial populations produce antibiotic-tolerant persister cells. A number of recent studies point to the involvement of toxin/antitoxin (TA) modules in persister formation. hipBA is a type II TA module that codes for the HipB antitoxin and the HipA toxin. HipA is an EF-Tu kinase, which causes protein synthesis inhibition and dormancy upon phosphorylation of its substrate. Antitoxins are labile proteins that are degraded by one of the cytosolic ATP-dependent proteases. We followed the rate of HipB degradation in different protease deficient strains and found that HipB was stabilized in a lon(-) background. These findings were confirmed in an in vitro degradation assay, showing that Lon is the main protease responsible for HipB proteolysis. Moreover, we demonstrated that degradation of HipB is dependent on the presence of an unstructured carboxy-terminal stretch of HipB that encompasses the last 16 amino acid residues. Further, substitution of the conserved carboxy-terminal tryptophan of HipB to alanine or even the complete removal of this 16 residue fragment did not alter the affinity of HipB for hipBA operator DNA or for HipA indicating that the major role of this region of HipB is to control HipB degradation and hence HipA-mediated persistence.

Image and video compression standards such as JPEG, MPEG, H.263 are highly sensitive to error during transmission. Among typical error propagation mechanisms in video compression schemes, loss of block synchronization produces the worst image degradation. Even an error of a single bit in block synchronization may result in data to be placed in wrong positions that is caused by spatial shifts. Our proposed efficient block error concealment code (EBECC) virtually guarantees block synchronization and it improves coding efficiency by several hundred folds over the error resilient entropy code (EREC), proposed by N. G. Kingsbury and D. W. Redmill, depending on the image format and size. In addition, the EBECC produces slightly better resolution on the reconstructed images or video frames than those from the EREC. Another important advantage of the EBECC is that it does not require redundancy contrasting to the EREC that requires 2-3 percent of redundancy. Our preliminary results show the EBECC is 240 times faster than EREC for encoding and 330 times for decoding based on the CIF format of H.263 video coding standard. The EBECC can be used on most of the popular image and video compression schemes such as JPEG, MPEG, and H.263. Additionally, it is especially useful to wireless networks in which the percentage of image and video data is high.