• Microbiology and Biotechnology Letters
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• v.51 no.3
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• pp.243-249
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• 2023

We recently found that the insect-derived antimicrobial peptide CopA3 (LLCIALRKK) directly binds to and inhibits the proteolytic activation of caspases, which play essential roles in apoptotic processes. However, the mechanism of CopA3 binding to caspases remained unknown. Here, using recombinant GST-caspase-3 and -6 proteins, we investigated the mechanism by which CopA3 binds to caspases. We showed that replacement of cysteine in CopA3 with alanine caused a marked loss in its binding activity towards caspase-3 and -6. Exposure to DTT, a reducing agent, also diminished their interaction, suggesting that this cysteine plays an essential role in caspase binding. Experiments using deletion mutants of CopA3 showed that the last N-terminal leucine residue of CopA3 peptide is required for binding of CopA3 to caspases, and that C-terminal lysine and arginine residues also contribute to their interaction. These conclusions are supported by binding experiments employing direct addition of CopA3 deletion mutants to human colonocyte (HT29) extracts containing endogenous caspase-3 and -6 proteins. In summary, binding of CopA3 to caspases is dependent on a cysteine in the intermediate region of the CopA3 peptide and a leucine in the N-terminal region, but that both an arginine and two adjacent lysines in the C-terminal region of CopA3 also contribute. Collectively, these results provide insight into the interaction mechanism and the high selectivity of CopA3 for caspases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2C
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• pp.342-347
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• 2004

An ID certificate is digitally signed by a certificate authority for authentication and an attribute certificate is digitally signed by an attribute certificate authority for authorization. In many applications in web, there should be a mechanism to bind attributes to proper identities. The dependencies between them should be maintained. So we analyzed some known binding methods, selective revocation methods and cryptographic binding methods. And we proposed a binding mechanism using one-time attribute certificates in order to solve their problems.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.207-213
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• 2009

The bundling process is the final step in vegetable manufacturing, however, the process is a little difficult to be automatized, because vegetable has the physical properties of roughness, softness, and fragility etc. In this paper, we proposed an automatic bundling mechanism for vegetable based on the heat melt sticking. The proposed mechanism consists of three modules, one module is the moving part for aligning of the vegetable shape and adjusting of the vegetable tension, second module is the arm driving part for the vegetable binding and the band roll releasing, and third module is band joining, band cutting, and band feeding part for the vegetable binding continuously. Through this research, Using the SMO(SimDesigner Motion) module, we optimize condition of mechanical movement of the bundling mechanism. This bundling system designed in order to binding 288 bundle/hour.

• Archives of Pharmacal Research
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• v.20 no.6
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• pp.579-585
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• 1997

To gain further insight into the mechanism of action of antiestrogens, we examined the interaction of antiestrogen with the estrogen receptor system and with estrogen- noncompetable antiestrogen binding sites. In addition to binding directly to the estrogen receptor, antiestrogens can be found associated with binding sites that are distinct from the estrogen receptor. In contrast to the restriction of estrogen receptors to estrogen target cells, such as those of uterus and mammary glands, antiestrogen binding sites are present in equal amounts in estrogen receptor-positive and -negative human breast cancer cell lines, such as MCF-7, T47D, and MDA-MB-231 that differ markedly in their sensitivity to antiestrogens. In order to gain greater insight into the role of these antiestrogen binding sites in the action of antiestrogens, we have examined the biopotency of different antiestrogens for the antiestrogen binding sites and that is CI628 > tamoxifen > trans-hydroxy tamoxifen > CI628M > H1285 > LY117018. This order of affinities does not parallel the affinity of these compounds for the estrogen receptor nor the potency of these compounds as antiestrogens. Indeed, compounds with high affinity for the estrogen receptor and greatest antiestrogenic potency have low affinities for these antiestrogen binding sites. Antiestrogenic potency correlates best with estrogen receptor affinity and not with affinity for antiestrogen binding sites. In summary, our findings suggested that interaction with the estrogen receptor is most likely the mechanism through which antiestrogens evoke their growth inhibitory effects.

• Journal of Microbiology
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• v.35 no.1
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• pp.15-20
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• 1997

Kinetic studies were done to elucidate the reaction mechanism of purine nucleoside phosphorylase (PNP) in Micrococcus Luteus. PNP catalyzes the reversible phosphorolysis of ribonucleosides to their respective base. The effect of alternative competing substrates suggested that a single enzyme was involved in binding to the active site for all purine nucleosides, inosine, deoxyiosine, guanosine, deoxyguanosine, adenosine and deoxyadenosine. Affinity studies showed that pentose moiety reduced the binding capacity and methylation of ring N-1 of inosine and guanosine had little effect on binding to bacterial enzyme, whereas these compounds did not bind to the mammalian enzymes. The initial velocity and product inhibition studies demonstrated that the predominant mechanism of reaction was an ordered bi, bi reaction. The nucleoside bound to the enzyme first, followed by phosphate. Ribose 1-phosphate was the first product to leave, followed by base.

• Journal of Nutrition and Health
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• v.30 no.8
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• pp.930-935
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• 1997

Fatty acid binging proteins(FABP) are distinct but related gene productes which are found in many mamalian cell types. FABP bind long chain fatty acids in vitro. However, their functions and mechanisms of action, in vivo, remain unknown . Also not known is whether all FABP function similaryly in their respective cell types. or whether different FABP have unique functions. The puropose of the present study was to assess whether different members of the FABP family exhibit different structural and function properties. A comparison was made between heart(H-FABP) and liver (L-FABP). The results show that the binding sites of both FABP are hydrophobic in nature, although the L-FABP site is more nonpolar than the H-FABP site. Additionally, the bound ligand experiences less motional constraint within the H-FABP binding site than within the L-FABP binding site. In accordance with these differences in structural properties, it was found that anthroyloxy-fatty acid transfer from H-FABP to membranes is markedly faster than from L-FABP. moreover, the mechanism of fatty acid transfer to phospholipid membranes appears to occur via transient collisional interactions between H-FABP and membranes. In contrast , transfer of fatty acid from L-FABP occurs via an aqueous diffusion mechanism.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.537-540
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• 2006

Over the past few decades, a considerable number of studies on the durability of concrete have been carried out extensively. A lot of improvements have been achieved especially in modeling of ionic flows. However, the majority of these researches have not dealt with the chloride binding isotherm based on the mechanism, although chloride binding capacity can significantly impact on the total service life of concrete under marine environment. The purpose of this study is to develop the model of chloride binding isotherm based on the individual mechanism. It is well known that chlorides ions in concrete can be present; free chlorides dissolved in the pore solution, chemical bound chlorides reacted with the hydration compounds of cement, and physical bound attracted to the surface of C-S-H grains. First, sub-model for water soluble chloride content is suggested as a function of pore solution and degree of saturation. Second, chemical model is suggested separately to estimate the response of binding capacity due to C-S-H and Friedel's salt. Finally, physical bound chloride content is estimated to consider a surface area of C-S-H nano-grains and the distance limited by the Van der Waals force. The new model of chloride binding isotherm suggested in this study is based on their intrinsic binding mechanisms and hydration reaction of concrete. Accordingly, it is possible to characterize chloride binding isotherm at the arbitrary stage of hydration time and arbitrary location from the surface of concrete. Comparative study with experimental data of published literature is accomplished to validity this model.

• Journal of Photoscience
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• v.11 no.32
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• pp.65-69
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• 2004

The mechanism of interaction of four coumarin derivatives (CDS) with bovine serum albumin (BSA) was studied using spectrofluorometric technique. It was found that the coumarin ring common to all CDS makes major contribution to interaction. Binding affinities could be related to parachor values of CDS. Stem-Volmer plots indicated the presence of static component in the quenching mechanism. Results also showed that both tryptophan residues of protein are accessible to CDS. The high magnitude of rate constant of quenching indicated that the process of energy transfer occurs by intermolecular interaction forces and thus CDS binding site is in close proximity to tryptophan residues of BSA. Binding studies in the presence of the hydrophobic probe, 8-anilino-l-naphthalein-sulfonic acid showed that there is hydrophobic interaction between CDS and the probe and they do not share common sites in BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CDS to BSA involve hydrophobic bonds predominantly. The effects of various metal ions on the binding of CDS with BSA were also investigated.

• Korean Journal of Microbiology
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• v.30 no.3
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• pp.181-186
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• 1992

Virginiae butanolide C (VB-C) binding protein binds to virginiamycin inducing factor and the protein may function as a possible pleiotropic signal transducer. To further understand signal transducing mechanism, some properties of VB-C binding protcin were investigated. VB-C binding activity was gradually increased during 60 hrs incubation: whereas the amount of produced VBs was not changed. However. VB-C hinding activity was decreased by 30-5096 in the presence of genome DNA. The binding protein could he phosphorylated by [$\gamma-^{32}\textrm{P}$] ATP. These results suggest that the DNA binding and phosphorylation may be involved in signal transducing mechanism.

• Molecules and Cells
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• v.44 no.11
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• pp.805-829
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• 2021

CCCTC-binding factor (CTCF) critically contributes to 3D chromatin organization by determining topologically associated domain (TAD) borders. Although CTCF primarily binds at TAD borders, there also exist putative CTCF-binding sites within TADs, which are spread throughout the genome by retrotransposition. However, the detailed mechanism responsible for masking the putative CTCF-binding sites remains largely elusive. Here, we show that the ATP-dependent chromatin remodeler, chromodomain helicase DNA-binding 4 (CHD4), regulates chromatin accessibility to conceal aberrant CTCF-binding sites embedded in H3K9me3-enriched heterochromatic B2 short interspersed nuclear elements (SINEs) in mouse embryonic stem cells (mESCs). Upon CHD4 depletion, these aberrant CTCF-binding sites become accessible and aberrant CTCF recruitment occurs within TADs, resulting in disorganization of local TADs. RNA-binding intrinsically disordered domains (IDRs) of CHD4 are required to prevent this aberrant CTCF binding, and CHD4 is critical for the repression of B2 SINE transcripts. These results collectively reveal that a CHD4-mediated mechanism ensures appropriate CTCF binding and associated TAD organization in mESCs.