Lipoxygenases (LOXs) are a family of nonheme iron dioxygenases that catalyze the regioselective and stereospecific hydroperoxidation of polyunsaturated fatty acids, and are involved in a variety of inflammatory diseases and cancers. The crystal structure of rabbit 15S-LOX1 that was reported by Gillmor et al. in 1997 has played key roles for understanding the properties of mammalian LOXs. In this structure, three segments, including 12 residues in the superficial alpha2 helix, are absent and have usually been described as "disordered." By reinterpreting the original crystallographic data we were able to elucidate two different conformations of the molecule, both having well ordered alpha2 helices. Surprisingly, one molecule contained an inhibitor and the other did not, thereby adopting a closed and an open form, respectively. They differed in the conformation of the segments that were absent in the original structure, which is highlighted by a 12 A movement of alpha2. Consequently, they showed a difference in the size and shape of the substrate-binding cavity. The new model should provide new insight into the catalytic mechanism involving induced conformational change of the binding pocket. It may also be helpful for the structure-based design of LOX inhibitors.

practical WSN applications. To address this issue, our group recently developed high-performance flexible energy harvesters by using single-crystalline piezoelectric materials with a high piezoelectric d 33 constant of above 2000 pC N -1 . [19][20][21] Although these energy harvesters provided instantaneous milli-Wattlevel peak power to operate various electronic and biomedical devices, the high production cost of single crystals could impede the commercialization of flexible piezoelectric energy harvesters. [22,23] The conventional sol-gel coating technique for dense piezoelectric films with a thickness of a few micrometers is also not favorable for industrial application due to the multiple tedious repetitions of both spin coating and heat treatment of each 100-nm layer to minimize film cracking caused by excessive tensile stress during the annealing process. [24] Aerosol deposition (AD), proposed by Akedo and Lebedev, can provide fast, thick, and cost-effective deposition of highquality piezoelectric films: [25] This unique AD process can instantaneously produce nanograined polycrystalline ceramic thick films that are up to several hundred micrometers in thickness, and which have similar piezoelectric properties to those of bulk ceramics on various substrates (e.g., silicon, sapphire, quartz, and metals) without cracking. [26,27] To facilitate highkinetic-energy bombardment of ceramic particles, micrometersized piezoelectric granules are accelerated to a nearly sonic speed (up to 300 m s -1 ) to collide with the target substrates at room temperature, followed by subsequent high-temperature grain growth to improve the piezoelectric properties of the AD films. [28] While application of AD ceramic films in piezoelectric fields such as microelectromechanical systems (MEMS) generators, actuators, and ultrasonic transducers was studied, AD films were not widely exploited for flexible applications due to their intrinsic brittleness and rigidity. [26] Here, we demonstrate a high-performance flexible piezoelectric energy harvester enabled by an AD-based PZT thick film on a plastic substrate to develop a self-powered wireless sensor-node system. A high-temperature (900 °C) annealed crystalline AD PZT film with a thickness of 7 μm on a rigid sapphire substrate was successfully transferred onto a flexible substrate by an inorganic-based laser lift-off (ILLO) without any structural damage or degradation of its properties. [29] Our flexible PZT harvesting device can generate an open-circuit voltage of 200 V and a short-circuit current of 35 μA by biomechanical bending/unbending motions. The high-output performance of the AD PZT harvester is comparable with the performance of a previous flexible single-crystal piezoelectric harvester, which is attributed to the high-temperature grain growth of AD films. [20]

A spatial confinement effect of copper nanoparticles in an ordered mesoporous γ-Al2O3, which is synthesized by an evaporation induced self-assembly (EISA) method, was investigated to verify the enhanced catalytic activity and stability with less aggregation of copper crystallites during direct synthesis of dimethyl ether (DME) from syngas. The surface acidity of the mesoporous Al2O3 and the metallic copper surface area significantly altered catalytic activity and stability. The ordered mesopore structures of Al2O3 were effective to suppress the aggregation of copper nanoparticles even under reductive CO hydrogenation conditions through the spatial confinement effect of the ordered mesopores of Al2O3 as well as the formation of strongly interacted copper nanoparticles with the mesoporous Al2O3 surfaces by partial formation of the interfacial CuAl2O4 species. The aggregation of copper nanoparticles on the bifunctional Cu/meso-Al2O3 having an ordered mesoporous structure was effectively suppressed due to the partial formation of the thermally stable spinel copper aluminate phases, which can further generate new acid sites for dehydration of methanol intermediate to DME.

UDP-glucose pyrophosphorylases (UGPase; EC 2.7.7.9) catalyze the conversion of UTP and glucose-1-phosphate to UDP-glucose and pyrophosphate and vice versa. Prokaryotic UGPases are distinct from their eukaryotic counterparts and are considered appropriate targets for the development of novel antibacterial agents since their product, UDP-glucose, is indispensable for the biosynthesis of virulence factors such as lipopolysaccharides and capsular polysaccharides. In this study, the crystal structures of UGPase from Helicobacter pylori (HpUGPase) were determined in apo- and UDP-glucose/Mg(2+)-bound forms at 2.9 A and 2.3 A resolutions, respectively. HpUGPase is a homotetramer and its active site is located in a deep pocket of each subunit. Magnesium ion is coordinated by Asp130, two oxygen atoms of phosphoryl groups, and three water molecules with octahedral geometry. Isothermal titration calorimetry analyses demonstrated that Mg(2+) ion plays a key role in the enzymatic activity of UGPase by enhancing the binding of UGPase to UTP or UDP-glucose, suggesting that this reaction is catalyzed by an ordered sequential Bi Bi mechanism. Furthermore, the crystal structure explains the specificity for uracil bases. The current structural study combined with functional analyses provides essential information for understanding the reaction mechanism of bacterial UGPases, as well as a platform for the development of novel antibacterial agents.

Escherichia coli SdiA is a quorum-sensing (QS) receptor that responds to autoinducers produced by other bacterial species to control cell division and virulence. Crystal structures reveal that E. coli SdiA, which is composed of an N-terminal ligand-binding domain and a C-terminal DNA-binding domain (DBD), forms a symmetrical dimer. Although each domain shows structural similarity to other QS receptors, SdiA differs from them in the relative orientation of the two domains, suggesting that its ligand-binding and DNA-binding functions are independent. Consistently, in DNA gel-shift assays the binding affinity of SdiA for the ftsQP2 promoter appeared to be insensitive to the presence of autoinducers. These results suggest that autoinducers increase the functionality of SdiA by enhancing the protein stability rather than by directly affecting the DNA-binding affinity. Structural analyses of the ligand-binding pocket showed that SdiA cannot accommodate ligands with long acyl chains, which was corroborated by isothermal titration calorimetry and thermal stability analyses. The formation of an intersubunit disulfide bond that might be relevant to modulation of the DNA-binding activity was predicted from the proximal position of two Cys residues in the DBDs of dimeric SdiA. It was confirmed that the binding affinity of SdiA for the uvrY promoter was reduced under oxidizing conditions, which suggested the possibility of regulation of SdiA by multiple independent signals such as quorum-sensing inducers and the oxidation state of the cell.

A high-performance magneto-mechano-triboelectric nanogenerator (MMTEG) is demonstrated for powering a wireless indoor positioning system.

The receptor activator of nuclear factor-κB (RANK) and its ligand RANKL, which belong to the tumor necrosis factor (TNF) receptor-ligand family, mediate osteoclastogenesis. The crystal structure of the RANKL ectodomain (eRANKL) in complex with the RANK ectodomain (eRANK) combined with biochemical assays of RANK mutants indicated that three RANK loops (Loop1, Loop2, and Loop3) bind to the interface of a trimeric eRANKL. Loop3 is particularly notable in that it is structurally distinctive from other TNF-family receptors and forms extensive contacts with RANKL. The disulfide bond (C125-C127) at the tip of Loop3 is important for determining the unique topology of Loop3, and docking E126 close to RANKL, which was supported by the inability of C127A or E126A mutants of RANK to bind to RANKL. Inhibitory activity of RANK mutants, which contain loops of osteoprotegerin (OPG), a soluble decoy receptor to RANKL, confirmed that OPG shares the similar binding mode with RANK and OPG. Loop3 plays a key role in RANKL binding. Peptide inhibitors designed to mimic Loop3 blocked the RANKL-induced differentiation of osteoclast precursors, suggesting that they could be developed as therapeutic agents for the treatment of osteoporosis and bone-related diseases. Furthermore, some of the RANK mutations associated with autosomal recessive osteopetrosis (ARO) resulted in reduced RANKL-binding activity and failure to induce osteoclastogenesis. These results, together with structural interpretation of eRANK-eRANKL interaction, provided molecular understanding for pathogenesis of ARO.

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