263 research outputs found
Estimation of Precipitable Water Using Numerical Prediction Data
Precipitable water (PW) is an important variable in the climate system. Interferometric synthetic aperture radar (InSAR) is a powerful remote sensing technique for measuring the topography and deformation of the Earth’s surface. However, variations in atmospheric water vapor content affect the accuracy of InSAR measurements. Therefore, it is important to understand the distribution of PW to mitigate atmospheric effects on remote sensing data. Herein, we estimated the PW distribution with high spatial resolution using numerical prediction data and digital elevation model (DEM) data from the Kanto region of Japan. We estimated the PW distribution at a resolution of 90 m from mesoscale model grid point value data while accounting for the difference in surface elevation within pixels using DEM data with a resolution of 90 m. The PW distribution at 90-m resolution could be estimated using the proposed method with good accuracy (root-mean-square difference within 4.0 mm) throughout the year. The proposed method provides high-resolution information on atmospheric water vapor content and its variation at 3-h intervals. This method is expected to be applicable in climate research and for the atmospheric correction of remote sensing data, which can improve the accuracy of remote sensing measurements
High affinity ligand binding by integrins does not involve head separation
Conformational change in the integrin extracellular domain is required for high affinity ligand binding and is also involved in post-ligand binding cellular signaling. Although there is evidence to the contrary, electron microscopic studies showing that ligand binding triggers α- and β-subunit dissociation in the integrin head-piece have gained popularity and support the hypothesis that head separation activates integrins. To test directly the head separation hypothesis, we enforced head association by introducing disulfide bonds across the interface between the α-subunit β-propeller domain and the β-subunit I-like domain. Basal and activation-dependent ligand binding by αIIbβ3 and αVβ3 was unaffected. The covalent linkage prevented dissociation of αIIbβ3 into its subunits on EDTA-treated cells. Whereas EDTA dissociated wild type αIIbβ3 on the cell surface, a ligand-mimetic Arg-Gly-Asp peptide did not, as judged by binding of complex-specific antibodies. Finally, a high affinity ligand-mimetic compound stabilized noncovalent association between αIIb and β3 headpiece fragments in the presence of SDS, indicating that ligand binding actually stabilized subunit association at the head, as opposed to the suggested subunit separation. The mechanisms of conformational regulation of integrin function should therefore be considered in the context of the associated αβ headpiece
GuideLink: A Corpus Annotation System that Integrates the Management of Annotation Guidelines
PACLIC 23 / City University of Hong Kong / 3-5 December 200
Key Interactions in Integrin Ectodomain Responsible for Global Conformational Change Detected by Elastic Network Normal-Mode Analysis
AbstractIntegrin, a membrane protein with a huge extracellular domain, participates in cell-cell and cell-extracellular-matrix interactions for metazoan. A group of integrins is known to perform a large-scale structural change when the protein is activated, but the activation mechanism and generality of the conformational change remain to be elucidated. We performed normal-mode analysis of the elastic network model on integrin αVβ3 ectodomain in the bent form and identified key residues that influenced molecular motions. Iterative normal-mode calculations demonstrated that the specific nonbonded interactions involving the key residues work as a snap to keep integrin in the bent form. The importance of the key residues for the conformational change was further verified by mutation experiments, in which integrin αIIbβ3 was used. The conservation pattern of amino acid residues among the integrin family showed that the characteristic pattern of residues seen around these key residues is found in the limited groups of integrin β-chains. This conservation pattern suggests that the molecular mechanism of the conformational change relying on the interactions found in integrin αVβ3 is unique to the limited types of integrins
Allosteric β\u3csub\u3e1\u3c/sub\u3e integrin antibodies that stabilize the low affinity state by preventing the swing-out of the hybrid domain
The ligand binding function of integrins can be modulated by various monoclonal antibodies by both direct and indirect mechanisms. We have characterized an anti-β1 antibody, SG/19, that had been reported to inhibit the function of the β1 integrin on the cell surface. SG/19 recognized the wild type β1 subunit that exists in a conformational equilibrium between the high and low affinity states but bound poorly to a mutant β1 integrin that had been locked in a high affinity state. Epitope mapping of SG/19 revealed that Thr82 in the β1 subunit, located at the outer face of the boundary between the I-like and hybrid domains, was the key binding determinant for this antibody. Direct visualization of the α5β1 headpiece fragment in complex with SG/19 Fab with electron microscopy confirmed the location of the binding surface and showed that the ligand binding site is not occluded by the bound Fab. Surface plasmon resonance showed that α5β1 integrin bound by SG/19 maintained a low affinity toward its physiological ligand fibronectin (Fn) whereas binding by function-blocking anti-α5 antibodies resulted in a complete loss of fibronectin binding. Thus a class of the anti-β antibodies represented by SG/19 attenuate the ligand binding function by restricting the conformational shift to the high affinity state involving the swing-out of the hybrid domain without directly interfering with ligand docking
Adsorption of benzene derivatives on allophane
The adsorption properties of benzene derivatives from water on allophane, extracted from soil, have been investigated by UV and FTIR spectroscopic measurements. Allophane adsorbs benzoic acid, phthalic acid, benzaldehyde, ethyl benzoate, and diethyl phthalate. Benzoic acid, phthalic acid, and benzaldehyde formed carboxylate anions on the positive sites of the hydrated alumina surface of allophane. In the case of adsorption from an acidic solution (pH 2), a small amount of a neutral species of benzoic acid was detected on the allophane. Ethyl benzoate and diethyl phthalate were adsorbed by an interaction between their carbonyl groups and the hydroxyl groups of the allophane. It was confirmed that allophane has an adsorption ability for the benzene derivatives that are not only ionic but also polar molecules. Allophane was found to be available as an absorbent for use in water purification by a simple procedure.ArticleAPPLIED CLAY SCIENCE. 43(2):160-163 (2009)journal articl
A clear separation of foraging areas between two neighboring colonies of Adelie Penguins observed in a year of extensive sea ice cover
The Tenth Symposium on Polar Science/Ordinary sessions : [OB] Polar Biology, Wed. 4 Dec. / Entrance Hall (1st floor) , National Institute of Polar Researc
Mechanistic basis for the recognition of laminin-511 by α6β1 integrin
Mamoru Takizawa, Takao Arimori, Yukimasa Taniguchi, Yu Kitago, Erika Yamashita, Junichi Takagi and Kiyotoshi Sekiguchi, "Mechanistic basis for the recognition of laminin-511 by α6β1 integrin", Science Advances, Vol. 3, No. 9, e1701497, AAAS, 201
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