• Biomedical Science Letters
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• v.9 no.2
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• pp.67-74
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• 2003

Viral and non-viral vectors have been used in the delivery of genetic materials into animal cells and tissues, with each approach having pros and cons. Non-viral vectors have many useful merits such as easy preparation, low immunity and size tolerance of a transgene when compared to those of viral vectors. Delivery specificity may be achieved by complex formation between receptor ligands and a non-viral vector. In the present study, non-viral vector systems are investigated in an effort to find a practical delivery means for gene therapy, Receptor-ligand interaction between transferrin-receptor and transferrin was utilized for efficient gene transfer into cancer cells. A plasmid vector, pcDNA3 (LacZ) was ligated with a small duplexed oligo fragment in which a Biotin- VN$^{TM}$ phosphoramidite was placed in the middle of the oligo. The plasmid vector labeled by biotin was then conjugated with biotin-labeled transferrin via streptavidin. This trimeric conjugates were delivered to a hepatoma cell line, HepG2. The delivery efficiency of the trimeric conjugate was 2-fold higher than that of cationic liposomes used for transfection of a plasmid vector. These results demonstrate that a plasmid vector can be efficiently transferred into cells by forming a trimeric complex of plasmid vector-linker-ligand.

• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.2106-2112
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• 2018

Concanavalin A (ConA) interacts with carbohydrates as a lectin, and recent reports proposed its application for detecting a diversity of viruses and pathogens. Structural studies have detailed the interaction between ConA and carbohydrates and the metal coordination environment with manganese and calcium ions (Mn-Ca-ConA). In this study, ConA was crystallized with a cadmium-containing precipitant, and the refined structure indicates that $Mn^{2+}$ was replaced by $Cd^{2+}$ (Cd-Ca-ConA). The structural comparison with ConA demonstrates that the metal-coordinated residues of Cd-Ca-ConA, that is Glu8, Asp10, Asn14, Asp19, and His24, do not have conformational shifts, but residues for sugar binding, including Arg228, Tyr100, and Leu99, reorient their side chains, slightly. Previous studies demonstrated that excess cadmium ions can coordinate with other residues, including Glu87 and Glu183, which were not coordinated with $Cd^{2+}$ in this study. The trimeric ConA in this study coordinated $Cd^{2+}$ with other residues, including Asp80 and Asp82, for complex generation. The monomer does not have specific interaction near interface regions with the other monomer, but secondary cadmium coordinated with two aspartates (Asp80 and Asp82) from monomer 1 and one aspartate (Asp16) from monomer 2. This study demonstrated that complex generation was induced via coordination with secondary $Cd^{2+}$ and showed the application potential regarding the design of complex formation for specific interactions with target saccharides.

• Biomedical Science Letters
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• v.10 no.3
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• pp.187-194
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• 2004

A short peptide corresponding to the nuclear localization signal (NLS) of human immunodeficiency virus (HIV)-l Tat protein, Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg, was employed to improve the efficiency of cellular uptake of nucleic acids. The peptide was first mixed with a reporter plasmid and then with cationic liposomes to form a tripartite complex of DNA/peptide/liposomes (DPL). Transfection efficiency of the DPL complex was compared with that of the conventional DNA/liposomes (DL) complex. When the DPL complex was formed with various cationic liposomes, DOTAP/DOPE (DP) liposome exhibited superior transfection efficiency to other liposomes tested in vitro. With the inclusion of the peptide, the DPL complex showed much enhanced transfection in various cancer cell lines. Particularly, transfection of the DPL complex in serum increased cellular uptake of a transgene up to 2 fold when compared with that in a serum free condition. Further, when the DPL complex was infused through the ureteric route of a rat, transfection efficiency was shown to be better in reporter gene expression than that obtained with the DL complex. This study shows that the DPL complex that is easy to formulate can be employed for much enhanced cellular uptake of a trans gene.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.321-326
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• 2016

Two new polymeric complexes, [Zn(dpa)(pyz)_0.5]_n (1; dpa = diphenate and pyz = pyrazine) and [Mn₃(bpdc)₃(py)₄]_n (2; bpdc = biphenyl-4,4'-dicarboxylate and py = pyridine) were successfully isolated by the hydro- and solvo-thermal technique, respectively. The complexes were characterized by elemental and thermal analysis, vibrational IR spectroscopy, and by single crystal x-ray structure determination. For 2, magnetic property was also investigated. Complex 1 is a two-dimensional layer structure consisting of a paddle-wheel building unit of Zn-dpa chains bridged by pyrazine. While, complex 2 consists of linear trimeric Mn3 cluster as building unit to form 3D network. In the complexes, dpa²⁻ (1) and bpdc²⁻(2) ligands show a typical bis-monodendate bridging and two kinds of bridging modes; a typical bridging and chelating/bridging mode, respectively.

• Molecules and Cells
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• v.25 no.1
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• pp.7-19
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• 2008

Complexins play a critical role in the control of fast synchronous neurotransmitter release. They operate by binding to trimeric SNARE complexes consisting of the vesicle protein Synaptobrevin and the plasma membrane proteins Syntaxin and SNAP-25, which are key executors of membrane fusion reactions. SNARE complex binding by Complexins is thought to stabilize and clamp the SNARE complex in a highly fusogenic state, thereby providing a pool of readily releasable synaptic vesicles that can be released quickly and synchronously in response to an action potential and the concomitant increase in intra-synaptic $Ca^{2+}$ levels. Genetic elimination of Complexins from mammalian neurons causes a strong reduction in evoked neurotransmitter release, and altered Complexin expression levels with consequent deficits in synaptic transmission were suggested to contribute to the etiology or pathogenesis of schizophrenia, Huntington's disease, depression, bipolar disorder, Parkinson's disease, Alzheimer's disease, traumatic brain injury, Wernicke's encephalopathy, and fetal alcohol syndrome. In the present review I provide a summary of available data on the role of altered Complexin expression in brain diseases. On aggregate, the available information indicates that altered Complexin expression levels are unlikely to have a causal role in the etiology of the disorders that they have been implicated in, but that they may contribute to the corresponding symptoms.

• BMB Reports
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• v.32 no.5
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• pp.419-428
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• 1999

Tumor necrosis factor (TNF) receptor members have unique structures composed of 2-4 cysteine - rich pseudorepeats in the extracellular domain. On ligation by trimeric ligand molecules, oligomerization of three receptor molecules occurs, which in turn activates the receptor and recruits intracellular signaling molecules to the cytoplasmic tail to initiate biological events. Recently, the numbers of tumor necrosis factor receptor and ligand family members have been rapidly expanding. Functional characterization of the new members has indicated redundant roles with other known members as well as provided insights into novel functions. In particular, identification of soluble decoy receptors which have the ability to bind multiple ligands highlights a complex control mechanism of immune responses by these molecules. Studies of the new members have also revealed that the TNF receptor and ligand family members play an important role in other than the immune system.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.58-58
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• 2003

The envelope glycoprotein of HIV, gp41, mediates the membrane fusion with human cells. The extracellular domain of gp41 has two helical regions. The N-terminus helical region (N-helix) forms trimeric coiled coil, interacts with the C-terminus helical region (C-helix) of gp41 to form a stable helical bundle structure. In this study, we have shown that the N-helix of gp41 has membrane interacting and disrupting abilities. It was localized into the interface of the lipidic phase and head group of the membrane. In contrast, the N-helix region with membrane fusion defective mutations could not bind to membrane. In addition, the N-helix bound on the membrane was released from the membrane by the C-helix, and the complex of the N- and C-helix did not interact with membrane. These results suggested that the membrane binding ability of the N-helix is necessary for the fusion activity of gp41, and such property is possibly controlled by the C-helm.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.3 no.3
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• pp.177-188
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• 1999

The effect of ABA on the chloroplast disassembly of Zea mays was investigated by measuring the changes in the relative distribution of chlorophyll(Chl) between the Chl-protein complexes in ABA treated and untreated sensecting leaves. The reaction center(RC)-light harvesting complex(LHC) regions were rapidly disassembled in the late stage of dark-induced senescence. Plus, during dark-induced senescence, the disassembly of a reaction center of P700 apoproteins containing mainly Chl a was faster than that of a reaction center of LHCI apoproteins containing both Chl a and Chl b. The increase in the relative distribution of Chl-protein complexes in the RC-Core2 in the late stage of senescence was due to the accumulation of core complexes such as CP47/43 and reaction centers including D1/D2 apoproteins disassembled from the RC-Corel containing the dimer of D1/D2 apoproteins. The LHCII region was more stable than the other Chl-protein complexes throughout leaf senscence. Accordingly, it is suggested that the preferential breakdown of Chl a gives rise to the disassembly of Chl a-binding proteins, particularly reaction centers and core complexes during dark-induced senescence, plus the primary target of the photosynthetic apparatus in sensecing leaves would seem to be Chl a along with the proteins associated with Chl a. The application of ABA promoted the disassembly of the P700 apoproteins in the PSI reaction center and the dimer of D1/D2 apoproteins, and the conversion of the trimeric LHCII apoprotein to the monometirc LHCII apoprotein during the middle stage of leaf senescence, thereby suggesting that ABA accelerates the disassembly of both Chl a-binding and Chl a+b-binding proteins, particularly Chl a-binding proteins during the middle stage of leaf senescence.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.1
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• pp.73-77
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• 2002

The Sec61 trimeric complex ($\alpha$,$\beta$, and ${\gamma}$ subunits) is one of the Sec-complex responsible for post-translational protein translocation across the endoplasmic reticulum membrane in diverse organisms. In this study, a cDNA encoding the Sec61p ${\gamma}$ subunit homologue was isolated from the cDNA library of the mole cricket, Gryllotalpa orientalis. Sequence analysis of a 442-bp cDNA clone showed it to contain an open reading frame of 68 amino acid residues consisted of 204-bp. The homologues of the gene were found in the GenBank database in a diverse organism including insect, mammals, fungi, and plants. The deduced amino acid sequence of Sec61p ${\gamma}$ subunit homologue of the mole cricket showed the highest homology to the gene of the singly known insect, Drosophila melanogester (93% identity), and the least homology to that of the baker's yeast, Saccharomyces cerevisiae (37.2%). Phylogenetic analysis also confirmed a close relationship between the insect Sec61p ${\gamma}$ subunit homologues of G. orientalis and D. melanogester. Hydropathy analysis of the cricket mole and published other data suggested that the hydrophobic segment close to C-terminus is predicted to be the putative membrane anchor, Multiple alignment of the Sec61p ${\gamma}$ subunit homologue among several organisms showed the presence of several conserved domains including the conserved proline at position 28.

• Journal of the Korean Chemical Society
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• v.40 no.3
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• pp.187-195
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• 1996

Ab initio SCF calculations have been carried out for the five conceivable trimers formed between one hydrogen cyanide and two hydrogen fluorides using a basis set of TZ＋P quality. Several ground state properties of these trimeric complexes have been evaluated, and compared with those of isolated monomers and appropriate dimers. Computed equilibrium geometries, stabilization energies, and dipole moments are given in order to suppliment the available experimental data. At this level of approximation, intramolecular bond distances are consistently shorter than experimental ones. However, intermolecular distances upon complex formation, and dipole moments are overestimated compared with experimental ones. HCN$(HF)_2$ trimer appears to be the most favourable among the five kinds of trimer complex, and also more stable than $(HCN)_2HF$. The typical features of the non-additivity of intermolecular interaction are relatively strong in the HCN$(HF)_2$ trimer.