• 한국분말재료학회지
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• 제27권6호
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• pp.477-483
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• 2020

Metal-organic frameworks (MOFs) are of significant interest because of their high porosity, which facilitates their utilization in gas storage and catalysis. To enhance their current properties in these applications, it is necessary to elucidate the interactions between molecules in a confined environment that differ from those in bulk conditions. Herein, we study the confined molecular interaction by investigating the solvent-dependent photophysical properties of two different-sized molecules inside MOF-5. Ruthenium tris-bipyridine (Rubpy) and coumarin 153 (C153) are encapsulated in MOF-5. Rubpy with MOF-5 (Rubpy@MOF) is prepared by building MOF-5 around it, resulting in limited space for solvent molecules in the pores. The smaller C153 is encapsulated in the preformed MOF-5 (C153@MOF) by simply soaking the MOF in a concentrated C153 solution. C153@MOF permits more space for solvent molecules in the pore. Their characteristic absorption and emission spectra are examined to elucidate the confined molecular interactions. Rubpy@MOF and C153@MOF exhibit different spectral shifts compared to the guest molecules under bulk conditions. This discrepancy is attributed to the different micro-environments inside the pores, derived from confined host-guest interactions in the interplay of solvent molecules.

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.843-852
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• 2003

We present a brief account of the theory of diffusion-influenced kinetics of reactions involving polymers. The review will be based on the recent contributions from the authors. Both intrapolymer and interpolymer reactions are considered, and the effects of various physical factors, such as the chain length, chain stiffness, and hydrodynamic interactions, are described within a unified theoretical framework.

• Journal of Photoscience
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• 제9권2호
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• pp.94-97
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• 2002

Light is one of the most important environmental factors that influence plant growth and development. It does not function independently but exerts its role through coordinated interactions with intrinsic developmental programs, such as hormonal regulation. One typical example is hypocotyl growth in which light signals are modulated through growth hormones. However, the underlying molecular mechanisms are largely unknown. We demonstrated that brassinosteroids play an important role in the light signal transduction in etiolated hypocotyl growth. A light-responsive Ras-like G-protein, Pra2 from pea, physically and functionally interacts with a cytochrome P450 that specifically catalyzes C-2 hydroxylation in brassinosteroid biosynthesis. The cytochrome P450 expression, along with Pra2, is induced in the dark and predominantly localized in the rapidly elongating zone of etiolated pea epicotyls. Transgenic plants with a reduced level of Pra2 exhibit a dark-specific dwarfism, which is completely rescued by brassinosteroid application. On the contrary, overexpression of the cytochrome P450 results in enhanced hypocotyl growth even in the light, which phenocopies the etiolated hypocotyl growth. It is therefore envisioned that Pra2 is a molecular switch that mediates the crosstalk between light and brassinosteroids in the etiolation process.

• BMB Reports
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• 제38권2호
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• pp.243-247
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• 2005

Dishevelled (Dvl) is a positive regulator of the canonical Wnt signaling pathway, which regulates the levels of $\beta$-catenin. The $\beta$-catenin oncoprotein depends upon the association of Dvl and Axin proteins through their DIX domains, and its accumulation directs the expression of specific developmental-related genes at the nucleus. Here, the $^1H$, $^{13}C$, and $^{15}N$ resonances of the human Dishevelled 2 DIX domain are assigned using heteronuclear nuclear magnetic resonance (NMR) spectroscopy. In addition, helical and extended elements are identified based on the NMR data. The results establish a structural context for characterizing the actin and phospholipid interactions and binding sites of this novel domain, and provide insights into its role in protein localization to stress fibers and cytoplasmic vesicles during Wnt signaling.

• Animal cells and systems
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• 제12권1호
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• pp.1-9
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• 2008

In the developing limb, chondrogenesis is an important prerequisite for the formation of cartilage whose template is required for bone formation. Chondrogenesis is a tightly regulated multi-step process, including mesenchymal cell recruitment/migration, prechondrogenic condensation of the mesenchymal cells, commitment to the chondrogenic lineage, and differentiation into chondrocytes. This process is controlled exquisitely by cellular interactions with the surrounding matrix and regulating factors that initiate or suppress cellular signaling pathways and transcription of specific genes in a temporal-spatial manner. Understanding the cellular and molecular mechanisms of chondrogenesis is important not only in the context of establishing basic principle of developmental biology but also in providing research direction toward preventive and/or regenerative medicine. Here, I will overview the current understanding of cellular and molecular mechanisms contributing to prechondrogenic condensation processes, the crucial steps for chondrogenesis, focusing on cell-cell and cell-matrix interactions.

• BMB Reports
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• 제45권4호
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• pp.213-220
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• 2012

Viruses have evolved to manipulate the host cell machinery for virus propagation, in part by interfering with the host cellular signaling network. Molecular studies of individual pathways have uncovered many viral host-protein targets; however, it is difficult to predict how viral perturbations will affect the signaling network as a whole. Systems biology approaches rely on multivariate, context-dependent measurements and computational analysis to elucidate how viral infection alters host cell signaling at a network level. Here we describe recent advances in systems analyses of signaling networks in both viral and non-viral biological contexts. These approaches have the potential to uncover virus- mediated changes to host signaling networks, suggest new therapeutic strategies, and assess how cell-to-cell variability affects host responses to infection. We argue that systems approaches will both improve understanding of how individual virus-host protein interactions fit into the progression of viral pathogenesis and help to identify novel therapeutic targets.

• BMB Reports
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• 제48권8호
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• pp.429-430
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• 2015

Angiogenesis is a complex process involving dynamic interaction of various cell to cell interactions. Endothelial cell interactions regulated by growth factors, inflammatory cytokines, or hemodynamic stress are critical for balancing vascular quiescence and activation. Yes-associated protein (YAP), an effector of Hippo signaling, is known to play significant roles in maintaining cellular homeostasis. However, its role in endothelial cells for angiogenic regulation remains relatively unexplored. We demonstrated the critical role of YAP in vascular endothelial cells and elucidated the underlying molecular mechanisms involved in angiogenic regulation of YAP. YAP was expressed in active angiogenic regions where endothelial cell junctions were relatively loosened. Consistently, YAP subcellular localization and activity were regulated by VE-cadherin-mediated PI3K/Akt pathway. YAP thereby regulated endothelial sprouting via angiopoietin-2 expression. These results provide an insight into a model of coordinating endothelial junctional stability and angiogenic activation through YAP. [BMB Reports 2015; 48(8): 429-430]

• Genomics & Informatics
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• 제19권2호
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• pp.18.1-18.8
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• 2021

G protein–coupled receptors (GPCRs), including olfactory receptors, account for the largest group of genes in the human genome and occupy a very important position in signaling systems. Although olfactory receptors, which belong to the broader category of GPCRs, play an important role in monitoring the organism's surroundings, their actual three-dimensional structure has not yet been determined. Therefore, the specific details of the molecular interactions between the receptor and the ligand remain unclear. In this report, the interactions between human olfactory receptor 1A1 and its odorant molecules were simulated using computational methods, and we explored how the chemically simple odorant molecules activate the olfactory receptor.

• Genomics & Informatics
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• 제19권1호
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• pp.9.1-9.5
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• 2021

Mammalian olfactory receptors are a family of G protein-coupled receptors (GPCRs) that occupy a large part of the genome. In human genes, olfactory receptors account for more than 40% of all GPCRs. Several types of GPCR structures have been identified, but there is no single olfactory receptor whose structure has been determined experimentally to date. The aim of this study was to model the interactions between an olfactory receptor and its ligands at the molecular level to provide hints on the binding modes between the OR2W1 olfactory receptor and its agonists and inverse agonists. The results demonstrated the modes of ligand binding in a three-dimensional model of OR2W1 and showed a statistically significant difference in binding affinity to the olfactory receptor between agonists and inverse agonists.

• Korean Chemical Engineering Research
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• 제59권4호
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• pp.644-651
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• 2021

Alkyl amines are widely used in various industries. Nowadays these are also used in CO₂ capture technology because amines react with CO₂ and remove it from the flue gas. To make the amines more compatible towards this technology, physico chemical properties may be altered by mixing with other solvents. In the present report, we measured the refractive properties of pure diisopropylamine (DIPA) (1) + isomeric butanol (2) at 298.15 K to 308.15 K. The 𝚫n values were positive for DIPA + n-butanol or sec-butanol or isobutanol or tert-butanol mixtures. The measured data was correlated with Redlich-Kister equation. The excess molar volume data were predicted from refractive index data using Nakata and Sakurai model. The experimental data were also predicted by various correlations, and the prediction capability of these correlations was reported through standard deviation. Further, the deviation in refractive index (𝚫n) data was interpreted by the consideration of specific molecular interactions between DIPA and isomeric butanol.