• 약학회지
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• 제36권5호
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• pp.469-473
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• 1992

Yeast alcohol dehydrogenase (YADH) has an acidic residue that interacts with the 2'- and 3'-hydroxyl groups of the adenosine ribose of the $NAD^+$ coenzyme. The acidic residue of Asp-223 (according to horse liver alcohol dehydrogenase amino acid sequence) is supposed to determine the coenzyme specificity for $NAD^+$ rather than $NADP^+$. We mutated Asp-223 to leucine and the mutant YADH was expressed in yeast and characterized for the coenzyme specificity. The turnover numbers of mutant enzyme for $NAD^+$ and ethanol were decreased 3.5- and 4.8-fold compared to wild-type enzyme, respectively. Contrastively, catalytic specificity for $NADP^+$ was increased 13-fold. As a result, the mutant YADH also employed $NADP^+$ as a coenzyme.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8487-8490
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• 2016

Background: Helicobacter pylori infection and premalignant gastric mucosa can be reliably identified using conventional narrow band imaging (C-NBI) gastroscopy. The aim of our study was to compare standard biopsy with site specific biopsy for diagnosis of H. pylori infection and premalignant gastric mucosa in daily clinical practice. Materials and Methods: Of a total of 500 patients who underwent gastroscopy for investigation of dyspeptic symptoms, 250 patients underwent site specific biopsy using C-NBI (Group 1) and 250 standard biopsy (Group 2). Sensitivity, specificity, and positive and negative predictive values were assessed. The efficacy of detecting H. pylori associated gastritis and premalignant gastric mucosa according to the updated Sydney classification was also compared. Results: In group 1 the sensitivity, specificity, positive and negative predictive values for predicting H. pylori positivity were 95.4%, 97.3%, 98.8% and 90.0% respectively, compared to 92.9%, 88.6%, 83.2% and 76.1% in group 2. Site specific biopsy was more effective than standard biopsy in terms of both H. pylori infection status and premalignant gastric mucosa detection (P<0.01). Conclusions: Site specific biopsy using C-NBI can improve detection of H. pylori infection and premalignant gastric mucosa in daily clinical practice.

• BMB Reports
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• 제53권12호
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• pp.611-621
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• 2020

Bacterial endoribonuclease toxins belong to a protein family that inhibits bacterial growth by degrading mRNA or rRNA sequences. The toxin genes are organized in pairs with its cognate antitoxins in the chromosome and thus the activities of the toxins are antagonized by antitoxin proteins or RNAs during active translation. In response to a variety of cellular stresses, the endoribonuclease toxins appear to be released from antitoxin molecules via proteolytic cleavage of antitoxin proteins or preferential degradation of antitoxin RNAs and cleave a diverse range of mRNA or rRNA sequences in a sequence-specific or codon-specific manner, resulting in various biological phenomena such as antibiotic tolerance and persister cell formation. Given that substrate specificity of each endoribonuclease toxin is determined by its structure and the composition of active site residues, we summarize the biology, structure, and substrate specificity of the updated bacterial endoribonuclease toxins.

• Applied Biological Chemistry
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• 제40권3호
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• pp.189-195
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• 1997

부위특이적 변이제작을 통하여 Achromobacter protease I (API)의 lysin에 대한특이성의 구조적 근거를 조사하였다. Lysine 특이성을 결정하는 결정기로서 예상되는 잔기중의 하나인 Glu190을 glutamine, aspartic acid, leucine으로 치환하였을 경우, 전구체단백질은 Iysine 특이성을 가진 완전한 활성효소로서 발현되어 자기촉매적으로 processing되었다. 다른 하나의 잔기인 Asp225을 asparagine, leucine으로 치환한 변이체에서는 불활성 전구체인 pro-API으로서 발현되었으나, 변이체 (D225E)의 경우는 서서히 자기촉매적으로 maturation 되었다. 성숙체인 변이체 (D225E)의 Iysylendopeptidase 활성은 wild-type APl의 0.25%이였으며, 이 활성의 감소는 기질 Iysine과 효소와의 친화력 감소가 주 원인이었다. 이러한 결과로부터 Asp225가 Iysylendopeptidase의 엄격한 기질특이성에 결정적인 역할을 담당한다는 것이 시사되었다. 한편, 변이체 (D225E)는 ornithine 기질에 대해서 효소활성 이 검출되지 않았다. 이 변이체의 촉매잔기인 Ser194가 native API과 마찬가지로 DFP, PMSF와 근본적으로 동일한 반응성이 있는 것으로 나타나 225번 위치의 methylene 1 unit 더 긴 측사는 subsite P1의 methylene 1 unit 짧은 측사에 의해 보상되지 않는다는 것을 알 수 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7241-7244
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• 2014

Background: To determine the accuracy of preoperative urinary symptoms, urinalysis, computed tomography (CT) and cystoscopic findings for the diagnosis of urinary bladder invasion in patients with colorectal cancer. Materials and Methods: Records of patients with colorectal cancer and a suspicion of bladder invasion, who underwent tumor resection with partial or total cystectomy between 2002 and 2013 at the Faculty of Medicine Siriraj Hospital, were reviewed. Correlations between preoperative urinary symptoms, urinalysis, cystoscopic finding, CT imaging and final pathological reports were analyzed. Results: This study included 90 eligible cases (71% male). The most common site of primary colorectal cancer was the sigmoid colon (44%), followed by the rectum (33%). Final pathological reports showed definite bladder invasion in 53 cases (59%). Significant features for predicting definite tumor invasion were gross hematuria (OR 13.6, sensitivity 39%, specificity 73%), and visible tumor during cystoscopy (OR 5.33, sensitivity 50%, specificity 84%). Predictive signs in CT imaging were gross tumor invasion (OR 7.07, sensitivity 89%, specificity 46%), abnormal enhancing mass at bladder wall (OR 4.09, sensitivity 68%, specificity 66%), irregular bladder mucosa (OR 3.53, sensitivity 70%, specificity 60% ), and loss of perivesical fat plane (OR 3.17, sensitivity 81%, specificity 43%). However, urinary analysis and other urinary tract symptoms were poor predictors of bladder involvement. Conclusions: The present study demonstrated that the most relevant preoperative predictors of definite bladder invasion in patients with colorectal cancer are gross hematuria, a visible tumor during cystoscopy, and abnormal CT findings.

• 디지털융복합연구
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• 제15권11호
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• pp.455-461
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• 2017

본 연구의 목적은 도시재생에 활용되는 그라피티가 공공미술로서 장소특정성을 어떻게 갖게 되는가를 밝히는 데 있다. 연구를 위해 공공미술의 장소특정성에 대한 개념 이해와 함께 그라피티의 장소특정성에 대한 이론적 배경을 알아보았고, 도시재생 사업에 적용된 공공미술로서 그라피티를 작가별로, 설치장소를 기준으로 차이를 비교분석해보면서, 동시에 그라피티가 설치된 장소의 특수성와 도시재생 프로젝트의 전체적 맥락에서 의미를 찾아보았다. 사례조사 대상은 2015년부터 도시재생 사업이 펼쳐지고 있는 동두천 보산동에 설치된 그라피티에 한정지었다. 분석 결과, 작가별 작품의 개별적 장소특정성보다는 디자인, 공예, 음악 및 축제 등 도시의 역사와 장소적 특수성이 반영된 문화콘텐츠와 융합되었을 때 개별작품의 장소특정성도 극대화되고 있음을 알 수 있었다. 본 연구의 결과는 그라피티가 융합 디자인 요소로서 도시의 문화콘텐츠와 융합될 때 장소특정성이 극대화되어 공공미술의 가치를 갖게 되며, 도시재생의 미디어로서도 기능을 할 수 있다는 점을 제시하고 있다.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1249-1253
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• 2007

A hyperthermostable endoglucanase from Pyrococcus horikoshii with the capability of hydrolyzing crystalline cellulose was analyzed. A protein engineering study was carried out to obtain a reduced-size mutant. Five amino acid residues at both the N- and C-terminus were found to be removable without any loss of activity or thermal stability. Site-directed mutagenesis was also performed on R102, N200, E201, H297, Y299, E342, and W377, residues possibly involved in the active center or in the recognition and binding of a cellulose substrate. The activity of the resulting mutants was considerably decreased, confirming that the mutated residues were all important for activity. A reduced-size enzyme, as active as the wild-type endoglucanase, was successfully obtained, plus the residues critical for its activity and specificity were confirmed. Consequently, an engineered enzyme with a reduced size was obtained, and the amino acids essential for activity were confirmed by site-directed mutagenesis and comparison with a known three-dimensional structure.

• 건축역사연구
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• 제26권1호
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• pp.71-82
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• 2017

Pavilions, follies, and installations provide a place with a new experience beyond that of simple garden architecture. From this point of view, this study tried to analyze the constructs in the Glass House site, which Philip Johnson has built for 50 years. After Chapter 1 Introduction, which summarized the background of the study, Chapter 2 investigated the design background of the landscape and the types of the constructs there. It also, studying literature on pavilions, follies, and installations, defined the basic meanings of them. Chapter 3 identified the features of each construct through the case studies of it, analyzing Johnson's intentions on it. These features are such as the applications of classical follies, the quotations of architectural history, fusion with art, architectural experiments, and the monuments of personal history. In conclusion, this study, finding the site specificity as a common feature of pavilions, follies, and installations, referred to two aspects of this, which are not only physical placeness but also cultural media.

• BMB Reports
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• 제35권5호
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• pp.513-517
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• 2002

We describe a new method for identifying the sequences that signal the start of translation, and the boundaries between exons and introns (donor and acceptor sites) in human mRNA. According to the mandatory keyword, ORGANISM, and feature key, CDS, a large set of standard data for each signal site was extracted from the ASCII flat file, gbpri.seq, in the GenBank release 108.0. This was used to generate the scoring matrices, which summarize the sequence information for each signal site. The scoring matrices take into account the independent nucleotide frequencies between adjacent bases in each position within the signal site regions, and the relative weight on each nucleotide in proportion to their probabilities in the known signal sites. Using a scoring scheme that is based on the nucleotide scoring matrices, the method has great sensitivity and specificity when used to locate signals in uncharacterized human genomic DNA. These matrices are especially effective at distinguishing true and false sites.

• BMB Reports
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• 제28권2호
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• pp.94-99
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• 1995

The properties of binding sites in the active site of $Zn^{2+}$-glycerophosphocholine cholinephosphodiesterase were examined using substrates and inhibitors of the enzyme. Phosphodiesterase hydrolyzed p-nitrophenylphosphocholine, p-aminophenylphosphocholine, and glycerophosphocholine, but did not hydrolyze either acylated glycerophosphocholine or bis (p-nitrophenyl)phosphate, suggesting a size limitation for interaction with a glyceryl moiety-binding subsite. The hydrolysis of p-nitrophenylphosphocholine was competitively inhibited by glycerophosphocholine and p-aminophenylphosphocholine, while glycerophosphoethanolamine was a weak inhibitor. The enzyme was also inhibited by choline, but not by ethanolamine. Thiocholine, a much more potent inhibitor than choline, was more inhibitory than cysteamine, suggesting a strict specificity of an anionic subsite adjacent to a $Zn^{2+}$ subsite. Of all oxyanions tested, the tellurite ion was found to strongly inhibit the enzyme by binding to a $Zn^{2+}$ subsite. The inhibitory role of tellurite was synergistically enhanced by tetraalkylammonium salts, but not by glycerol. Deactivation of the enzyme by diethylpyrocarbonate was partially protected by choline, but not by glycerophosphate. It is suggested that the active site of phosphodiesterase contains three binding subsites.