• Bulletin of the Korean Chemical Society
• /
• 제32권4호
• /
• pp.1263-1267
• /
• 2011

Novel binol-based uryl and guanidinium receptors having higher ring conjugation at the periphery of the hydrogen bonding donor sites have been synthesized and utilized to study the enantioselective recognition of 1,2-aminoalcohols and chirality conversion of natural amino acids via imine bond formation. There is a remarkable decrease in the stereoselectivites as the conjugation increases at the periphery of hydrogen bonding donor sites. The guanidinium-based receptors show more selectivity towards the amino alcohol than that of the uryl based ones due to its charge reinforced hydrogen bonds. The conversion efficiency of L-amino acids to Damino acids by the uryl-based receptors is higher than that of the guanidinium-based ones.

• 공업화학
• /
• 제24권3호
• /
• pp.291-298
• /
• 2013

공액 리놀레산 메틸에스테르는 불균일계 촉매인 니켈 담지 제올라이트계 촉매를 이용하여 리놀레산 메틸에스테르의 이성질화를 통해 합성할 수 있다. 니켈 담지 제올라이트계 촉매는 HY 제올라이트로부터 KCl 수용액을 이용해 이온교환하여 KY 제올라이트를 합성한 뒤 함침법을 통해 니켈을 담지하여 합성하였다. 합성된 촉매는 수소를 이용하여 전처리하여 공액화 반응에 사용하였다. 그 결과 낮은 온도에서 HY 촉매는 높은 전환율을 나타내었지만 공액화 반응에 대해 낮은 선택도를 나타내었다. KY 촉매는 낮은 온도에서 상대적으로 낮은 전환율을 나타내었으나 높은 온도에서 HY 촉매와 유사한 전환율을 보였으며, 낮은 온도에서도 공액화 반응에 대해 높은 선택도를 나타내었다. 결과적으로 반응 온도 $220^{\circ}C$에서 4 wt% Ni/KY720을 이용하여 가장 높은 63.4%의 수율을 얻었다.

• BMB Reports
• /
• 제52권8호
• /
• pp.496-501
• /
• 2019

Conventionally, immunotoxins have been produced as a single polypeptide from fused genes of an antibody fragment and a toxin. In this study, we adopted a unique approach of chemical conjugation of a toxin protein and an antibody fragment. The two genes were separately expressed in Escherichia coli and purified to high levels of purity. The two purified proteins were conjugated using a chemical linker. The advantage of this approach is its ability to overcome the problem of low recombinant immunotoxin production observed in some immunotoxins. Another advantage is that various combinations of immunotoxins can be prepared with fewer efforts, because the chemical conjugation of components is relatively simpler than the processes involved in cloning, expression, and purification of multiple immunotoxins. As a proof of concept, the scFv of trastuzumab and the PE24 fragment of Pseudomonas exotoxin A were separately produced using E. coli and then chemically crosslinked. The new immunotoxin was tested on four breast cancer cell lines variably expressing HER2. The chemically crosslinked immunotoxin exhibited cytotoxicity in proportion to the expression level of HER2. In conclusion, the present study revealed an alternative method of generating an immunotoxin that could effectively reduce the viability of HER2-expressing breast cancer cells. These results suggest the effectiveness of this method of immunotoxin crosslinking as a suitable alternative for producing immunotoxins.

• 농업과학연구
• /
• 제44권1호
• /
• pp.30-39
• /
• 2017

This study was performed to produce succinic acid from biomass by developing mutants of Cellulomonas flavigena in which the succinate dehydrogenase gene (sdh) is deleted. For development of succinate producing mutants, the upstream and downstream regions of sdh gene from C. flavigena and antibiotic resistance gene (neo, bla) were inserted into pKC1139, and the recombinant plasmids were transformed into Escherichia coli ET12567/pUZ8002 which is a donor strain for conjugation. C. flavigena was conjugated with the transformed E. coli ET12567/pUZ8002 to induce the deletion of sdh in chromosome of this bacteria by double-crossover recombination. Two mutants (C. flavigena H-1 and H-2), in which sdh gene was deleted in the chromosome, were constructed and confirmed by PCR. To estimate the production of succinic acid by the two mutants when the culture broth was fermented with biomass such as CMC, xylan, locust gum, and rapeseed straw; the culture broth was analyzed by HPLC analysis. The succinic acid in the culture broth was not detected as a fermentation products of all biomass. One of the reasons for this may be the conversion of succinic acid to fumaric acid by sdh genes (Cfla_1014 - Cfla_1017 or Cfla_1916 - Cfla_1918) which remained in the chromosomal DNA of C. flavigena H-1 and H-2. The other reason could be the conversion of succinyl-CoA to other metabolites by enzymes related to the bypass pathway of TCA cycle.

• Journal of Photoscience
• /
• 제8권1호
• /
• pp.23-25
• /
• 2001

The methyl pheophorbide-a (MP-a) and methyl pyropheophorbide-a (MPP-a) were modified by reaction of exocyclic ketone in E-ring with nucleophilic reagent and several chlorin derivatives were synthesized. The change of the structure in E-ring served an expanding conjugation region and introduction of electron-withdrawing group, which strongly influenced the visible spectra. The Qy bands of synthesized compounds were affected by the substituents on the Qy axis(N$\sub$21/-N$\sub$23/).

• 한국미생물·생명공학회지
• /
• 제39권2호
• /
• pp.104-110
• /
• 2011

방선균은 그램양성 토양 박테리아로서 항생제, 항암제, 항구충제, 면역억제제 등 유용한 2차 대사산물을 생산하는 유용 산업미생물이다. 비록 대부분의 방선균이 속해있는 스트렙토마이세스는 지난 수 십 년간 분자수준에서의 연구가 집중적으로 진행되어 왔으나, 최근에 분리된 잠재적 유용성을 갖는 스트렙토마이세스 이외의 희소방선균들은 유전자 조작시스템의 부재로 그 특성이 잘 규명되지 않고 있다. 본 연구에서는 독립적으로 분리된 180 여 방선균주들 중에서 희소방선균만을 선별하기 위하여 중합효소연쇄반응을 이용한 유전체 스크리닝 전략을 시도하였으며, 이 전략을 통하여 7종의 희소방선균을 성공적으로 분리하였다. 특히 여러 생리활성 테스트를 통하여, 항진균 및 항생제 활성을 띄는 잠재적 유용성이 높은 노카이디옵시스 균주 MMBL010을 선별하였다. 또한 전통적인 방선균 유전자 조작기법이 작동하지 않는 본 MMBL010 균주를 대장균 접합을 통한 유전자 전달 시스템도 최적화시킴으로써, 유전체 스크리닝을 통한 유용희소방선균의 선별 및 유전자 조작시스템 구축은 궁극적으로 희소방선균의 잠재적 유용성을 극대화시킬 수 있는 효율적인 전략으로 사료된다.

• Journal of Microbiology and Biotechnology
• /
• 제32권9호
• /
• pp.1209-1216
• /
• 2022

To better understand the effects of PEGylation and biotinylation on the delivery efficiency of proteins, the cationic protein lysozyme (LZ) and anionic protein bovine serum albumin (BSA) were chemically conjugated with poly(ethylene glycol) (PEG) and biotin-PEG to primary amine groups of proteins using N-hydroxysuccinimide reactions. Four types of protein conjugates were successfully prepared: PEGylated LZ (PEG-LZ), PEGylated BSA (PEG-BSA), biotin-PEG-conjugated LZ (Bio-PEG-LZ), and biotin-PEG-conjugated BSA (Bio-PEG-BSA). PEG-LZ and Bio-PEG-LZ exhibited a lower intracellular uptake than that of LZ in A549 human lung cancer cells (in a two-dimensional culture). However, Bio-PEG-BSA showed significantly improved intracellular delivery as compared to that of PEG-BSA and BSA, probably because of favorable interactions with cells via biotin receptors. For A549/fibroblast coculture spheroids, PEG-LZ and PEG-BSA exhibited significantly decreased tissue penetration as compared with that of unmodified proteins. However, Bio-PEG-BSA showed tissue penetration comparable to that of unmodified BSA. In addition, citraconlyated LZ (Cit-LZ) showed reduced spheroid penetration as compared to that of LZ, probably owing to a decrease in protein charge. Taken together, chemical conjugation of targeting ligands-PEG to anionic proteins could be a promising strategy to improve intracellular delivery and in vivo activity, whereas modifications of cationic proteins should be more delicately designed.

• Toxicological Research
• /
• 제26권2호
• /
• pp.101-108
• /
• 2010

Halogenated organic compounds, such as 1-bromobutane (1-BB), have been used as cleaning agents, agents for chemical syntheses or extraction solvents in workplace. In the present study, immunotoxic effects of 1-BB and its conjugation with glutathione (GSH) were investigated in female BALB/c mice. Animals were treated orally with 1-BB at 375, 750 and 1500 mg/kg in corn oil once for dose response or treated orally with 1-BB at 1500 mg/kg for 6, 12, 24 and 48 hr for time course. S-Butyl GSH was identified in spleen by liquid chromatography-electrospray ionization tandem mass spectrometry. Splenic GSH levels were significantly reduced by single treatment with 1-BB. S-Butyl GSH conjugates were detected in spleen from 6 hr after treatment. Oral 1-BB significantly suppressed the antibody response to a T-dependent antigen and the production of splenic intracellular interlukin-2 in response to Con A. Our present results suggest that 1-BB could cause immunotoxicity as well as reduction of splenic GSH content, due to the formation of GSH conjugates in mice. The present results would be useful to understand molecular toxic mechanism of low molecular weight haloalkanes and to develop biological markers for exposure to haloalkanes.

• Journal of Microbiology and Biotechnology
• /
• 제33권10호
• /
• pp.1351-1360
• /
• 2023

Endocrine-disrupting chemicals (EDCs) are compounds that disturb hormonal homeostasis by binding to receptors. EDCs are metabolized through hepatic enzymes, causing altered transcriptional activities of hormone receptors, and thus necessitating the exploration of the potential endocrine-disrupting activities of EDC-derived metabolites. Accordingly, we have developed an integrative workflow for evaluating the post-metabolic activity of potential hazardous compounds. The system facilitates the identification of metabolites that exert hormonal disruption through the integrative application of an MS/MS similarity network and predictive biotransformation based on known hepatic enzymatic reactions. As proof-of-concept, the transcriptional activities of 13 chemicals were evaluated by applying the in vitro metabolic module (S9 fraction). Identified among the tested chemicals were three thyroid hormone receptor (THR) agonistic compounds that showed increased transcriptional activities after phase I+II reactions (T3, 309.1 ± 17.3%; DITPA, 30.7 ± 1.8%; GC-1, 160.6 ± 8.6% to the corresponding parents). The metabolic profiles of these three compounds showed common biotransformation patterns, particularly in the phase II reactions (glucuronide conjugation, sulfation, GSH conjugation, and amino acid conjugation). Data-dependent exploration based on molecular network analysis of T3 profiles revealed that lipids and lipid-like molecules were the most enriched biotransformants. The subsequent subnetwork analysis proposed 14 additional features, including T4 in addition to 9 metabolized compounds that were annotated by prediction system based on possible hepatic enzymatic reaction. The other 10 THR agonistic negative compounds showed unique biotransformation patterns according to structural commonality, which corresponded to previous in vivo studies. Our evaluation system demonstrated highly predictive and accurate performance in determining the potential thyroid-disrupting activity of EDC-derived metabolites and for proposing novel biotransformants.

• Interdisciplinary Bio Central
• /
• 제4권3호
• /
• pp.9.1-9.7
• /
• 2012

Filamentous phages have been in the limelight as a new type of nanomaterial. In this study, genetically and chemically modified fd phage was used to generate a biomimetic phage self-assembly product. Positively charged fd phage (p8-SSG) was engineered by conjugating 3-aminopropyltriethoxysilane (APTES) to hydroxyl groups of two serine amino acid residues introduced at the N-terminus of major coat protein, p8. In particular, formation of a phage network was controlled by changing mixed ratios between wild type fd phage and APTES conjugated fd-SSG phage. Assembled phages showed unique bundle and network like structures. The bacteriophage based self-assembly approach illustrated in this study might contribute to the design of three dimensional microporous structures. In this work, we demonstrated that the positively charged APTES conjugated fd-SSG phages can assemble into microstructures when they are exposed to negatively charged wild-type fd phages through electrostatic interaction. In summary, since we can control the phage self-assembly process in order to obtain bundle or network like structures and since they can be functionalized by means of chemical or genetic modifications, bacteriophages are good candidates for use as bio-compatible scaffolds. Such new type of phage-based artificial 3D architectures can be applied in tuning of cellular structures and functions for tissue engineering studies.