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crystal structure transporter

Benoît Boucher, Rabih Al Rahal Al Orabi, Bruno Fontaine, Yuri Grin, Régis Gautier, Jean-François Halet
The possible existence of group 6 TM3 compounds with T = Cr, Mo, W and M = Ga, In is investigated with the aid of density functional theory calculations. Their most probable crystal structure is expected to be of the FeGa3 type tetragonal space group P42/mnm. All compounds are computed to be semiconductors with a band gap ranging from 0.08 to 0.43 eV, at the modified Becke-Johnson level of theory. The thermoelectric properties are analyzed via calculations based on Boltzmann transport equation under a constant relaxation time approximation...
March 20, 2017: Inorganic Chemistry
Liwen Mu, Yifan Li, Nitin Mehra, Tuo Ji, Jiahua Zhu
In this work, polyvinyl alcohol (PVA)/amino acid (AA) composites were prepared by a self-organized crystallization process. Five different AAs (cysteine, aspartic acid, glutamic acid, ornithine-HCl and lysine-HCl) were selected based on their similar functional groups but different molecular structure. The different PVA-AA interactions in the five PVA/AA composites lead to two crystal patterns, i.e. continuous network (cysteine and lysine-HCl) and discrete particles (glutamic acid, ornithine-HCl and aspartic acid)...
March 20, 2017: ACS Applied Materials & Interfaces
Xiaolong Xu, Qingjun Song, Haifeng Wang, Pan Li, Kun Zhang, Yilun Wang, Kai Yuan, Zichen Yang, Yu Ye, Lun Dai
The group IV-VI compound tin selenide (SnSe) has recently attracted particular interest due to its unexpectedly low thermal conductivity and high power factor, showing great promise for thermoelectric applications. With an orthorhombic lattice structure, SnSe displays intriguing anisotropic properties due to the low symmetry of the puckered in-plane lattice structure. When thermoelectric materials, like SnSe, have decreased dimensionality, their thermoelectric conversion efficiency may be improved due to increased power factor and decreased thermal conductivity...
March 20, 2017: ACS Applied Materials & Interfaces
Gracian Tejral, Bruno Sopko, Alois Necas, Wilhelm Schoner, Evzen Amler
Hydrolysis of ATP by Na(+)/K(+)-ATPase, a P-Type ATPase, catalyzing active Na(+) and K(+) transport through cellular membranes leads transiently to a phosphorylation of its catalytical α-subunit. Surprisingly, three-dimensional molecular structure analysis of P-type ATPases reveals that binding of ATP to the N-domain connected by a hinge to the P-domain is much too far away from the Asp(369) to allow the transfer of ATP's terminal phosphate to its aspartyl-phosphorylation site. In order to get information for how the transfer of the γ-phosphate group of ATP to the Asp(369) is achieved, analogous molecular modeling of the M4-M5 loop of ATPase was performed using the crystal data of Na(+)/K(+)-ATPase of different species...
2017: PeerJ
Masashi Kurokawa, Judy Fe F Jose-Larong, Hiroyuki Hasegawa, Yukihiro Takahashi, Jun Harada, Tamotsu Inabe
An axially ligated Co(tmp) (tmp = 5,10,15,20-tetramethylporphyrinato) anion, [Co(III)(tmp)(CN)2](-), has been prepared and subjected to electrochemical oxidation to obtain the open shell tmp π-ligand. With acetone as the solvent, solvent-free neutral radical crystals of Co(III)(tmp)(CN)2 are obtained, whereas solvent-inclusive crystals of Co(III)(tmp)(CN)2·2CH3CN are obtained with CH3CN as the solvent. In both crystals, the open shell tmp ring deforms into a ruffled form, which makes the π-π interactions in the crystal weak...
March 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Y Liu, Y J Long, L X Zhao, S M Nie, S J Zhang, Y X Weng, M L Jin, W M Li, Q Q Liu, Y W Long, R C Yu, C Z Gu, F Sun, W G Yang, H K Mao, X L Feng, Q Li, W T Zheng, H M Weng, X Dai, Z Fang, G F Chen, C Q Jin
Recently, theoretical studies show that layered HfTe5 is at the boundary of weak &strong topological insulator (TI) and might crossover to a Dirac semimetal state by changing lattice parameters. The topological properties of 3D stacked HfTe5 are expected hence to be sensitive to pressures tuning. Here, we report pressure induced phase evolution in both electronic &crystal structures for HfTe5 with a culmination of pressure induced superconductivity. Our experiments indicated that the temperature for anomaly resistance peak (Tp) due to Lifshitz transition decreases first before climbs up to a maximum with pressure while the Tp minimum corresponds to the transition from a weak TI to strong TI...
March 16, 2017: Scientific Reports
Michael Taschner, André Mourão, Mayanka Awasthi, Jerome Basquin, Esben Lorentzen
Motile cilia are found on unicellular organisms such as the green alga Chlamydomonas reinhardtii, on sperm cells, and on cells that line the trachea and fallopian tubes in mammals. The motility of cilia relies on a number of large protein complexes including the force-generating outer dynein arms (ODAs). The transport of ODAs into cilia has been previously shown to require the transport adaptor ODA16 as well as the intraflagellar transport (IFT) protein IFT46, but the molecular mechanism by which ODAs are recognized and transported into motile cilia is still unclear...
March 15, 2017: Journal of Biological Chemistry
Jiyoung Oh, Helen F Gleeson, Ingo Dierking
The application of an electric field to microspheres suspended in a liquid crystal causes particle translation in a plane perpendicular to the applied field direction. Depending on applied electric field amplitude and frequency, a wealth of different motion modes may be observed above a threshold, which can lead to linear, circular, or random particle trajectories. We present the stability diagram for these different translational modes of particles suspended in the isotropic and the chiral nematic phase of a liquid crystal and investigate the angular velocity, circular diameter, and linear velocity as a function of electric field amplitude and frequency...
February 2017: Physical Review. E
Monika R VanGordon, Gaurav Gyawali, Steven W Rick, Susan B Rempe
Channelrhodopsins (ChR1 and ChR2) are light-activated ion channels that enable photomobility of microalgae from the genus Chlamydomonas. Despite common use of ChR2 in optogenetics for selective control and monitoring of individual neurons in living tissue, the protein structures remain unresolved. Instead, a crystal structure of the ChR chimera (C1C2), an engineered combination of helices I-V from ChR1, without its C-terminus, and helices VI-VII from ChR2, is used as a template for ChR2 structure prediction...
March 14, 2017: Biophysical Journal
Jinhua Hong, Chuanhong Jin, Jun Yuan, Ze Zhang
Two-dimensional layered graphene-like crystals including transition-metal dichalcogenides (TMDs) have received extensive research interest due to their diverse electronic, valleytronic, and chemical properties, with the corresponding optoelectronics and catalysis application being actively explored. However, the recent surge in two-dimensional materials science is accompanied by equally great challenges, such as defect engineering in large-scale sample synthesis. It is necessary to elucidate the effect of structural defects on the electronic properties in order to develop an application-specific strategy for defect engineering...
March 10, 2017: Advanced Materials
Nicholas J Goble, Richard Akrobetu, Hicham Zaid, Sukrit Sucharitakul, Marie-Hélène Berger, Alp Sehirlioglu, Xuan P A Gao
The crystal structure of bulk SrTiO3(STO) transitions from cubic to tetragonal at around 105 K. Recent local scanning probe measurements of LaAlO3/SrTiO3 (LAO/STO) interfaces indicated the existence of spatially inhomogeneous electrical current paths and electrostatic potential associated with the structural domain formation in the tetragonal phase of STO. Here we report a study of temperature dependent electronic transport in combination with the polarized light microscopy of structural domains in mesoscopic LAO/STO devices...
March 15, 2017: Scientific Reports
Yang-Yang Lv, Lin Cao, Xiao Li, Bin-Bin Zhang, Kang Wang, Bin Pang, Ligang Ma, Dajun Lin, Shu-Hua Yao, Jian Zhou, Y B Chen, Song-Tao Dong, Wenchao Liu, Ming-Hui Lu, Yulin Chen, Yan-Feng Chen
Transition metal dichalcogenides (TMDs) WTe2 and MoTe2 with orthorhombic Td phase, being potential candidates as type-II Weyl semimetals, are attracted much attention recently. Here we synthesized a series of miscible Mo1-xWxTe2 single crystals by bromine vapor transport method. Composition-dependent X-ray diffraction and Raman spectroscopy, as well as composition and temperature-dependent resistivity prove that the tunable crystal structure (from hexagonal (2H), monoclinic (β) to orthorhombic (Td) phase) can be realized by increasing W content in Mo1-xWxTe2...
March 15, 2017: Scientific Reports
Kyounghwan Kim, Ashley DaSilva, Shengqiang Huang, Babak Fallahazad, Stefano Larentis, Takashi Taniguchi, Kenji Watanabe, Brian J LeRoy, Allan H MacDonald, Emanuel Tutuc
According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moiré patterns produced by small misalignments between its individual layer honeycomb lattices. We have realized bilayer graphene moiré crystals with accurately controlled twist angles smaller than 1° and studied their properties using scanning probe microscopy and electron transport. We observe conductivity minima at charge neutrality, satellite gaps that appear at anomalous carrier densities for twist angles smaller than 1°, and tunneling densities-of-states that are strongly dependent on carrier density...
March 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
Madhumati Sevvana, Kristin Hasselt, Florian C Grau, Andreas Burkovski, Yves A Muller
AmtR belongs to the TetR family of transcription regulators and is a global nitrogen regulator that is induced under nitrogen-starvation conditions in Corynebacterium glutamicum. AmtR regulates the expression of transporters and enzymes for the assimilation of ammonium and alternative nitrogen sources, for example urea, amino acids etc. The recognition of operator DNA by homodimeric AmtR is not regulated by small-molecule effectors as in other TetR-family members but by a trimeric adenylylated PII-type signal transduction protein named GlnK...
March 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
Shunya Sakurai, Taisuke Tomita, Toshiyuki Shimizu, Umeharu Ohto
FYVE and coiled-coil domain-containing protein 1 (FYCO1), a multidomain autophagy adaptor protein, mediates microtubule plus-end-directed autophagosome transport by interacting with kinesin motor proteins and with the autophagosomal membrane components microtubule-associated protein 1 light chain 3 (LC3), Rab7 and phosphatidylinositol 3-phosphate (PI3P). To establish the structural basis for the recognition of FYCO1 by LC3, the crystal structure of mouse LC3B in complex with the FYCO1 LC3-interacting region (LIR) motif peptide was determined...
March 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
R Kamal Saravanan, Prithwidip Saha, Viruthakasi Venkatesh, Thiruvancheril G Gopakumar, Sandeep Verma
Growth of a silver coordination polymer of a C3-symmetric hexaadenine ligand is studied on highly oriented pyrolytic graphite (HOPG), using high-resolution atomic force microscopy (AFM). This unusual ligand offers 6-fold multidentate coordination sites, and consequently, a multidimensional growth of coordination polymer is expected. Notably, each discrete hexapodal unit is bridged by two silver ions along one of the crystallographic directions, resulting in high interaction energy along this direction. When the polymer was deposited on an HOPG surface from a dilute solution, we observed abundant one-dimensional (1D) coordination polymer chains, with a minimum width of approximately 4...
March 14, 2017: Inorganic Chemistry
Jingwei Weng, Shuo Gu, Xin Gao, Xuhui Huang, Wenning Wang
Maltose transporter MalFGK2 is a type-I importer in the ATP-binding cassette (ABC) transporter superfamily. Upon the binding of its periplasmic binding protein, MalE, the ATPase activity of MalFGK2 can be greatly enhanced. Crystal structures of the MalFGK2-MalE-maltose complex in a so-called "pretranslocation" ("pre-T") state with a partially closed conformation suggest that the formation of this MalE-stabilized intermediate state is a key step leading to the outward-facing catalytic state. On the contrary, crosslinking and fluorescence studies suggest that ATP binding alone is sufficient to promote the outward-facing catalytic state, thereby doubting the role of MalE binding...
March 7, 2017: Physical Chemistry Chemical Physics: PCCP
Carlo Grazianetti, Eugenio Cinquanta, Li Tao, Paola De Padova, Claudio Quaresima, Carlo Ottaviani, Deji Akinwande, Alessandro Molle
The structural and electronic properties of nanoscale Si epitaxially grown on Ag(111) can be tuned from a multilayer silicene phase, where the constitutive layers incorporate a mixed sp(2)/sp(3) bonding, to other ordinary Si phases, such as amorphous and diamond-like Si. Based on comparative scanning tunneling microscopy and Raman spectroscopy investigations, a key role in determining the nanoscale Si phase is played by the growth temperature of the epitaxial deposition on Ag(111) substrate and the presence or absence of a single layer silicene as a seed for the successive growth...
March 6, 2017: ACS Nano
Esben M Quistgaard, Maria Martinez Molledo, Christian Löw
Major facilitator superfamily (MFS) peptide transporters (typically referred to as PepT, POT or PTR transporters) mediate the uptake of di- and tripeptides, and so play an important dietary role in many organisms. In recent years, a better understanding of the molecular basis for this process has emerged, which is in large part due to a steep increase in structural information. Yet, the conformational transitions underlying the transport mechanism are still not fully understood, and additional data is therefore needed...
2017: PloS One
Diana S Himmelstein, Ivelisse Cajigas, Chunming Bi, Brian S Clark, Grant Van Der Voort, Jhumku D Kohtz
Sonic hedgehog (SHH) is a master developmental regulator. In 1995, the SHH crystal structure predicted that SHH-E176 (human)/E177 (mouse) regulates signaling through a Zn(2+)-dependent mechanism. While Zn(2+) is known to be required for SHH protein stability, a regulatory role for SHH-E176 or Zn(2+) has not been described. Here, we show that SHH-E176/177 modulates Zn(2+)-dependent cross-linking in vitro and is required for endogenous signaling, in vivo. While ectopically expressed SHH-E176A is highly active, mice expressing SHH-E177A at endogenous sites (Shh(E177A/-)) are morphologically indistinguishable from mice lacking SHH (Shh(-/-)), with patterning defects in both embryonic spinal cord and forebrain...
March 2, 2017: Developmental Biology
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