• Journal of Microbiology and Biotechnology
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• 제15권5호
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• pp.1022-1027
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• 2005

Based on plasmid display technology by the complexes of fusion protein and the encoding plasmid DNA, an in vitro selection method for high affinity DNA-binding protein was developed and experimentally demonstrated. The GAL4 DNA-binding domain (GAL4 DBD) was selected as a model DNA-binding protein, and enhanced green fluorescent protein (EGFP) was used as an expression reporter for the selection of target proteins. Error prone PCR was conducted to construct a mutant library of the model. Based on the affinity decrease with increased salt concentration, mutants of GAL4 DBD having high affinity were selected from the mutant protein library of protein-encoding plasmid complex by this method. Two mutants of (Lys33Glu, Arg123Lys, Ile127Lys) and (Ser47Pro, Ser85Pro) having high affinity were obtained from the first generation mutants. This method can be used for rapid in vitro selection of high affinity DNA-binding proteins, and has high potential for the screening of high affinity DNA-binding proteins in a sequence-specific manner.

• 미생물학회지
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• 제49권2호
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• pp.211-214
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• 2013

비스페놀 A (BPA)는 내분비계 장애물질의 하나로서 인간에게 큰 위협이 되고 있는 물질이다. 따라서 BPA의 분석 및 제거를 위해 BPA에 대해 선택적 친화성을 보이는 특정 리간드 탐색이 요구되고 있다. 본 연구에서는 초음파 처리를 동반한 바이오패닝 기법을 이용하여 파지 표면 디스플레이 라이브러리로부터 BPA에 친화성이 높은 펩타이드 서열을 탐색하였다. BPA 입자에 대한 6라운드의 positive 스크리닝과 에펜도르프 튜브 표면 재질에 대한 negative 스크리닝 과정을 실시하였고, 이를 통해 BPA에 선택적 친화성이 높은 CysLysSerLeuGluAsnSerTyrCys (CKSLENSYC) 서열을 스크리닝하였다. 또한 확보된 서열의 선택적 친화성을 검증하기 위해 BPA와 구조가 유사한 비스페놀 F (BPF), 비스페놀 S (BPS)에 대해서 교차 친화성이 있는지 평가하였고, 앞에서 선택된 서열이 BPS, BPF에 비하여 상대적으로 BPA에 대한 친화성이 높다는 것을 확인하였다.

• 생명과학회지
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• 제7권3호
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• pp.167-171
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• 1997

번역개시 및 인산화의 조절에 관여하는 RNA와 단백질의 결합 및 인식기작을 연구하기 위해서[$\alpha$^{-32}$P] UMP-labeled HIV Rev-responsive element(RRE) RNA를 이용한 affinity screening에 이해서 Hela ZA-PII cDNA library로부터 이중선RNA결합단백질의 cDNA (RBFII)를 분리하였다. RBFII의 cDNA에 대한 염기서열을 결정하였으며 기존에 연구된 바 있는 RBFII(RBF 또는 TRBP로 보고되었으며 본 연구에서는 RBFII와 구분하기 위해 RBFI으로 명명)과 대부분의 경우 공통적인 ORF를 지니는 것으로 나타났다. 그러나 5’말단에서는 공통적인 ORF 가 RBFI의 경우 21개의 아미노산을 의미하는 63 nt가 Lac-Z의 N-말단에 연결된데 비해서 특이한 46개 아미노기를 의미하는 138nt가 존재함이 밝혀졌다. 5’-말단에 처음 나타나는 ATG 및 부근의 염기서열을 분석해 볼 때 양 cDNA는 5’말단이 완전하지 않은 것으로 사료된다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권3호
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• pp.1571-1576
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• 2016

Alteration of the acetylation status of chromatin and other non-histone proteins by HDAC inhibitors has evolved as an excellent epigenetic strategy in treatment of cancers. The present study was sought to identify compounds with positive pharmacological profiles targeting HDAC1. Analogues of Vorinostat synthesized by Cai et al, 2015 formed the test compounds for the present pharmacological evaluation. Hydroxamte analogue 6H showed superior pharmacological profile in comparison to all the compounds in the analogue dataset owing to its better electrostatic interactions and hydrogen bonding patterns. In order to identify compounds with even better high affinity and pharmacological profile than 6H and Vorinostat, virtual screening was performed. A total of 83 compounds similar to Vorinostat and 154 compounds akin to analogue 6H were retrieved. SCHEMBL15675695 (PubCid: 15739209) and AKOS019005527 (PubCid: 80442147) similar to Vorinostat and 6H, were the best docked compounds among the virtually screened compounds. However, in spite of having good affinity, none of the virtually screened compounds had better affinity than that of 6H. In addition SCHEMBL15675695 was predicted to be a carcinogen while AKOS019005527 is Ames toxic. From, our extensive analysis involving binding affinity analysis, ADMET properties predictions and pharmacophoric mappings, we report Vorinostat hydroxamate analogue 6H to be a potential candidate for HDAC inhibition in treatment of cancers through an epigenetic strategy.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3759-3765
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• 2015

Background: Approaches in disruption of MDM2-p53 interactions have now emerged as an important therapeutic strategy in resurrecting wild type p53 functional status. The present study highlights virtual screening strategies in identification of high affinity small molecule non-peptidic inhibitors. Nutlin3A and RG7112 belonging to compound class of Cis-imidazoline, MI219 of Spiro-oxindole class and Benzodiazepine derived TDP 665759 served as query small molecules for similarity search with a threshold of 95%. The query molecules and the similar molecules corresponding to each query were docked at the transactivation binding cleft of MDM2 protein. Aided by MolDock algorithm, high affinity compound against MDM2 was retrieved. Patch Dock supervised Protein-Protein interactions were established between MDM2 and ligand (query and similar) bound and free states of p53. Compounds with PubCid 68870345, 77819398, 71132874, and 11952782 respectively structurally similar to Nutlin3A, RG7112, Mi219 and TDP 665759 demonstrated higher affinity to MDM2 in comparison to their parent compounds. Evident from the protein-protein interaction studies, all the similar compounds except for 77819398 (similar to RG 7112) showed appreciable inhibitory potential. Of particular relevance, compound 68870345 akin to Nutlin 3A had highest inhibitory potential that respectively showed 1.3, 1.2, 1.16 and 1.26 folds higher inhibitory potential than Nutilin 3A, MI 219, RG 7112 and TDP 1665759. Compound 68870345 was further mapped for structure based pharamacophoric features. In the study, we report Cis-imidazoline derivative compound; Pubcid: 68870345 to have highest inhibitory potential in blocking MDM2-p53 interactions hitherto discovered.

• BMB Reports
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• 제29권3호
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• pp.205-209
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• 1996

To investigate the role of heparin in keratinocyte growth factor (KGF) and acidic fibroblast growth factor (aFGF) high affinity binding to the KGF receptor (KGFR), a cell free system was established which utilized a secreted chimeric molecule between the KGFR extracellular domain and the immunoglobulin heavy chain Fc domain (KGFR-HFc). KGFR-HFc was purified from NIH 3T3 cells and demonstrated the binding of $[^3H]-heparin$ as well as heparin Sepharose. Scatchard analysis showed that the dissociation constant for heparin binding to KGFR-HFc was 140 nM. High affinity KGF and aFGF binding to KGFR-HFc remained unchanged after treatment with 0.6 M NaCl, which is the concentration sufficient to release any bound heparin to the KGFR-HFc. These results strongly suggest that although the KGFR interacts with heparin, the presence of heparin is not absolutely required for high affinity binding of either KGF or aFGF to the KGFR.

• Journal of Information Technology Applications and Management
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• 제27권4호
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• pp.37-48
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• 2020

This research proposes how to enhance low customer satisfaction with health screening services caused by procedural complexity and limits of health screening. The purpose of this study is to identify sub-components of the service quality provided by general health examination centers. This is a qualitative analysis of in-depth interviews of providers and consumers of medical services. The data were primarily analyzed by affinity diagram, and the data were sorted and analyzed according to the criteria suggested by Donabedian's four components. Four types of quality factors and the health screening service quality components of 39 subordinate items were assessed. Components related to the use of IT facilities comprise a significant amount of the physical factors, and there are high demands for IT facilities among customers.

• Asian Pacific Journal of Cancer Prevention
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• 제16권9호
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• pp.3817-3825
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• 2015

Background: The human protein methyl-transferase DOT1L catalyzes the methylation of histone H3 on lysine 79 (H3K79) at homeobox genes and is also involved in a number of significant processes ranging from gene expression to DNA-damage response and cell cycle progression. Inhibition of DOT1L activity by shRNA or small-molecule inhibitors has been established to prevent proliferation of various MLL-rearranged leukemia cells in vitro, establishing DOT1L an attractive therapeutic target for mixed lineage leukemia (MLL). Most of the drugs currently in use for the MLL treatment are reported to have low efficacy, hence this study focused on various natural compounds which exhibit minimal toxic effects and high efficacy for the target receptor. Materials and Methods: Structures of human protein methyl-transferase DOT1L and natural compound databases were downloaded from various sources. Virtual screening, molecular docking, dynamics simulation and drug likeness studies were performed for those natural compounds to evaluate and analyze their anti-cancer activity. Results: The top five screened compounds possessing good binding affinity were identified as potential high affinity inhibitors against DOT1L's active site. The top ranking molecule amongst the screened ligands had a Glide g-score of -10.940 kcal/mol and Glide e-model score of -86.011 with 5 hydrogen bonds and 12 hydrophobic contacts. This ligand's behaviour also showed consistency during the simulation of protein-ligand complex for 20000 ps, which is indicative of its stability in the receptor pocket. Conclusions: The ligand obtained out of this screening study can be considered as a potential inhibitor for DOT1L and further can be treated as a lead for the drug designing pipeline.

• KSBB Journal
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• 제28권3호
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• pp.185-190
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• 2013

For the selection of peptide specifically binding to $Pb^{2+}$, the biopanning with the commercially available Ph.D.-7 phage displayed heptapeptide library was carried out against $Pb^{2+}$ immobilized on a metal-chelating IDA (iminodiacetic acid) resin. After four rounds of screening against $Pb^{2+}$-IDA including negative selections against charged bead with metal ions other than $Pb^{2+}$ and uncharged bead, several candidate lead-binding phage peptides were initially determined based on the order of frequency from the screened phage clones. Of the selected phage peptide sequences, the peptide of the highest frequency, CysSerIleArgThrLeuHisGlnCys (CSIRTLHQC) also exhibited the strongest affinity for $Pb^{2+}$ in binding assays for individual phage clones. However, there was not a significant difference in $Pb^{2+}$ affinity between selected peptides when using synthetic heptapeptides corresponding to the displayed peptide sequences of phage clones.

• BMB Reports
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• 제39권1호
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• pp.55-60
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• 2006

We describe a phage display strategy, based on the differential resistance of proteins to denaturant-induced unfolding, that can be used to select protein variants with improved conformational stability. To test the efficiency of this strategy, wild-type and two stable variants of ${\alpha}_1$-antitrypsin (${\alpha}_1AT$) were fused to the gene III protein of M13 phage. These phages were incubated in unfolding solution containing denaturant (urea or guanidinium chloride), and then subjected to an unfavorable refolding procedure (dialysis at $37^{\circ}C$). Once the ${\alpha}_1AT$ moiety of the fusion protein had unfolded in the unfolding solution, in which the denaturant concentration was higher than the unfolding transition midpoint ($C_m$) of the ${\alpha}_1AT$ variant, around 20% of the phage retained binding affinity to anti-${\alpha}_1AT$ antibody due to a low refolding efficiency. Moreover, this affinity reduced to less than 5% when 10 mg/mL skimmed milk (a misfolding-promoting additive) was included during the unfolding/refolding procedure. In contrast, most binding affinity (>95%) remained if the ${\alpha}_1AT$ variant was stable enough to resist unfolding. Because this selection procedure does not affect the infectivity of M13, the method is expected to be generally applicable to the high-throughput screening of stable protein variants, when activity-based screening is not possible.