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61.
Synthesis and purification of self‐assembling peptide‐oligonucleotide conjugates by solid‐phase peptide fragment condensation 下载免费PDF全文
Peptide‐oligonucleotide conjugates (POCs) are interesting molecules as they covalently combine 2 of the most important biomacromolecules. Sometimes, the synthesis of POCs involves unexpected difficulties; however, POCs with self‐assembling propensity are even harder to synthesize and purify. Here, we show that solid‐phase peptide fragment condensation combined with thiol‐maleimide or copper‐catalyzed azide‐alkyne cycloaddition click chemistries is useful for the syntheses of self‐assembling POCs. We describe guidelines for the selection of reactive functional groups and their placement during the conjugation reaction and consider the cost‐effectiveness of the reaction. Purification is another important challenge during the preparation of POCs. Our results show that polyacrylamide gel electrophoresis under denaturing conditions is most suitable to recover a high yield of self‐assembling POCs. This report provides the first comprehensive study of the preparation of self‐assembling POCs, which will lay a foundation for the development of elegant and sophisticated molecular assemblies. 相似文献
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Ju Yeon Song Susan E. Jensen Kye Joon Lee 《Applied microbiology and biotechnology》2010,88(3):659-669
Clavulanic acid, a β-lactamase inhibitor, is used together with β-lactam antibiotics to create drug mixtures possessing potent
antimicrobial activity. In view of the clinical and industrial importance of clavulanic acid, identification of the clavulanic
acid biosynthetic pathway and the associated gene cluster(s) in the main producer species, Streptomyces clavuligerus, has been an intriguing research question. Clavulanic acid biosynthesis was revealed to involve an interesting mechanism
common to all of the clavam metabolites produced by the organism, but different from that of other β-lactam compounds. Gene
clusters involved in clavulanic acid biosynthesis in S. clavuligerus occupy large regions of nucleotide sequence in three loci of its genome. In this review, clavulanic acid biosynthesis and
the associated gene clusters are discussed, and clavulanic acid improvement through genetic manipulation is explained. 相似文献
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Engineering of primary carbohydrate metabolism for increased production of actinorhodin in Streptomyces coelicolor 总被引:1,自引:0,他引:1
The objectives of the current studies were to determine the roles of key enzymes in central carbon metabolism in the context of increased production of antibiotics in Streptomyces coelicolor. Genes for glucose-6-phosphate dehydrogenase and phosphoglucomutase (Pgm) were deleted and those for the acetyl coenzyme A carboxylase (ACCase) were overexpressed. Under the conditions tested, glucose-6-phosphate dehydrogenase encoded by zwf2 plays a more important role than that encoded by zwf1 in determining the carbon flux to actinorhodin (Act), while the function of Pgm encoded by SCO7443 is not clearly understood. The pgm-deleted mutant unexpectedly produced abundant glycogen but was impaired in Act production, the exact reverse of what had been anticipated. Overexpression of the ACCase resulted in more rapid utilization of glucose and sharply increased the efficiency of its conversion to Act. From the current experiments, it is concluded that carbon storage metabolism plays a significant role in precursor supply for Act production and that manipulation of central carbohydrate metabolism can lead to an increased production of Act in S. coelicolor. 相似文献
66.
Variation in expression of gastric leptin according to differentiation and growth pattern in gastric adenocarcinoma 总被引:5,自引:0,他引:5
Hong SJ Kwon KW Kim SG Ko BM Ryu CB Kim YS Moon JH Cho JY Lee JS Lee MS Shim CS Kim BS 《Cytokine》2006,33(2):66-71
Leptin is an adipocyte-derived hormone that regulates body fat stores and feeding behavior. The presence of leptin in stomach epithelium was recently demonstrated in the rat and humans, and gastric leptin has been linked to the control of meal size, local inflammatory responses, and paracrine and autocrine functions through leptin receptors in the stomach. We compared the expression patterns of leptin and of the long variant of the leptin receptor (Ob-Rb) between areas with non-ulcerated mucosa and with hyperplastic polyps, adenoma, or adenocarcinoma to evaluate the expression relative to different disease states. Leptin and Ob-Rb were expressed in hyperplastic polyps, adenoma, and adenocarcinoma. In the gastric adenocarcinoma, leptin was expressed significantly less in the poorly differentiated and diffuse-type groups than in the well-differentiated and moderately differentiated groups or in the intestinal type. Based upon our findings, we suggest the possibility that leptin expression can have a pathophysiologic role about the differentiation or growth pattern of gastric adenocarcinoma. A further series of experiments is necessary to elucidate the pathophysiological role of leptin in the differentiation of gastric adenocarcinoma. 相似文献
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New bis-pyridinium oxime reactivators connected with CH2O(CH2)n OCH2 linkers between two pyridinium rings were designed and synthesized, and their reactivation potency was evaluated for AChE inhibited by organophosphorus VX agent. Among the prepared compounds, 1,2-dimethoxy-ethylene-bis-N,N'-4-pyridiumaldoxime dichloride 5a was the most potent and appeared to be the most promising compound as a potential reactivator for AChE inhibited by organophosphorus VX agent. 相似文献
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Wang KW Lee KG Park TJ Lee YC Yang JW Kim do H Lee SJ Park JY 《Biotechnology and bioengineering》2012,109(1):289-294
We developed a novel one-pot synthetic strategy for preparing monodisperse polyethylene glycol diacrylate (PEGDA) microdroplets via organoclay-assisted interfacial polymerization approach for Escherichia coli encapsulation. Based on the mechanism of spontaneous and rapid polymerization of PEGDA precursor solution with Mg-organoclay, the prepared PEGDA microdroplets have uniform size and fine round shape, with size range of 74-118 μm. The size of microdroplets can be controlled through the changing continuous phase flow rate. Organoclay-assisted polymerization method provides a unique environment to produce non-toxic ways of fabricating microorganism encapsulated microdroplets and to prohibit microdroplets merge during the processes. Furthermore, we successfully carried out to entrap E. coli inside of the PEGDA microdroplets. E. coli expressing a green fluorescent protein shows a good viability inside the PEGDA microdroplets. The in situ microfluidic synthetic method provides a novel approach for the preparation of monodisperse PEGDA microdroplets via a one-pot route. 相似文献
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Renukaradhya K. Math Shah Md. Asraful Islam Kye Man Cho Sun Joo Hong Jong Min Kim Myoung Geun Yun Ji Joong Cho Jae Young Heo Young Han Lee Hoon Kim Han Dae Yun 《Biodegradation》2010,21(4):565-573
3,5,6-trichloro-2-pyridinol (TCP) is a major metabolite of the insecticide chlorpyrifos and is hazardous to human and animal health. A gene encoding a TCP degrading enzyme was cloned from a metagenomic library prepared from cow rumen. The gene (tcp3A) is 2.5 kb in length, encoding a protein (Tcp3A) of 599 amino acid residues. Tcp3A has a potential signal sequence, as well as a putative ATP/GTP binding site, and a likely amidation site. The molecular weight of the enzyme is 62 kDa by SDS–PAGE. Comparison of Tcp3A with the NCBI database using BLASTP revealed homology to amidohydrolase proteins. Recombinant Escherichia coli harboring the tcp3A gene could utilize TCP as the sole source of carbon. TLC and HPLC revealed that TCP was degraded by recombinant E. coli harboring tcp3A. This is the first report of a gene encoding a TCP degrading enzyme. 相似文献
70.
Keunhong Jeong Woo Young Chung Young-Sik Kye Dongwook Kim 《Bioorganic & medicinal chemistry》2010,18(7):2598-2601
Type 2 diabetes mellitus (T2DM) is characterized by a substantial reduction in β-cell mass and the amyloid fibrils which are formed by the aggregation of the human islet amyloid polypeptide (h-IAPP) in the islet of Langerhans. Cleavage agents with Co(III) cyclen as the catalytic group have been studied as a novel therapeutic option for T2DM patients. However, recent research has suggested that the cytotoxicity of h-IAPP might be mediated by interactions with Cu(II); furthermore, it has been shown in vitro that Cu(II) prevents h-IAPP from forming the β-sheet conformers. Therefore, we synthesized a cleavage agent using Cu(II) cyclen. The resulting cleaved fragments and estimated cleavage yield (8.3 mol %) were evaluated after incubation with h-IAPP. 相似文献