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https://www.readbyqxmd.com/read/30105908/streptococcus-pneumoniae-sialidase-spnanb-catalyzed-one-pot-multienzyme-opme-synthesis-of-2-7-anhydro-sialic-acids-as-selective-sialidase-inhibitors
#1
An Xiao, Teri J Slack, Yanhong Li, Dashuang Shi, Hai Yu, Wanqing Li, Yang Liu, Xi Chen
Streptococcus pneumoniae sialidase SpNanB is an intramolecular trans-sialidase (IT-sialidase) and a virulence factor that is essential for streptococcal infection of the upper and lower respiratory tract. SpNanB catalyzes the formation of 2,7-anhydro- N-acetylneuraminic acid (2,7-anhydro-Neu5Ac), a potential prebiotic that can be used as the sole carbon source of a common human gut commensal anaerobic bacterium. We report here the development of an efficient one-pot multienzyme (OPME) system for synthesizing 2,7-anhydro-Neu5Ac and its derivatives...
August 23, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/30105625/a-fluorometric-sensing-method-for-sensitive-detection-of-trypsin-and-its-inhibitor-based-on-gold-nanoclusters-and-gold-nanoparticles
#2
Mengke Wang, Dandan Su, Guannan Wang, Xingguang Su
In this work, a facile, label-free, and sensitive fluorometric strategy for detection of trypsin and its inhibitor was established on the basis of the fluorescence resonance energy transfer (FRET) between mercaptoundecanoic acid functionalized gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) via protamine as a bridge. Protamine can trigger the aggregation of AuNPs and link AuNCs with aggregated AuNPs through electrostatic interaction. Compared with monodisperse AuNPs, the UV-vis absorption band of aggregated AuNPs overlapped considerably with the emission spectrum of AuNCs...
October 2018: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/30059557/study-of-purinosome-assembly-in-cell-based-model-systems-with-de-novo-purine-synthesis-and-salvage-pathway-deficiencies
#3
Veronika Baresova, Vaclava Skopova, Olga Souckova, Matyas Krijt, Stanislav Kmoch, Marie Zikanova
BACKGROUND: The enzymes involved in de novo purine synthesis (DNPS), one of the basic processes in eukaryotic cells, transiently and reversibly form a dynamic multienzyme complex called the purinosome in the cytoplasm. The purinosome has been observed in a broad spectrum of cells, but some studies claim that it is an artefact of the constructs used for visualization or stress granules resulting from the exposure of cells to nutrient-reduced growth media. Both may be true depending on the method of observation...
2018: PloS One
https://www.readbyqxmd.com/read/30019587/development-and-optimization-of-an-in-vitro-multienzyme-synthetic-system-for-production-of-kaempferol-from-naringenin
#4
Zhiping Zhang, Yanzhi He, Yue Huang, Li Ding, Lei Chen, Yaxian Liu, Yesen Nie, Xinyue Zhang
An in vitro multienzyme synthetic system was developed and optimized to efficiently produce kaempferol in a single reaction tube. Two key genes, Atf3h and Atfls1, in the biosynthetic pathway of kaempferol were cloned into a prokaryotic expression vector and overexpressed in Escherichia coli. The recombinant proteins were purified through affinity chromatography and showed activities of flavanone 3-hydroxylase and flavonol synthase, respectively, followed by development of an in vitro synthetic system for producing kaempferol...
August 8, 2018: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/30004385/lipoate-binding-proteins-and-specific-lipoate-protein-ligases-in-microbial-sulfur-oxidation-reveal-an-atpyical-role-for-an-old-cofactor
#5
Xinyun Cao, Tobias Koch, Lydia Steffens, Julia Finkensieper, Renate Zigann, John E Cronan, Christiane Dahl
Many Bacteria and Archaea employ the heterodisulfide reductase (Hdr)-like sulfur oxidation pathway. The relevant genes are inevitably associated with genes encoding lipoate-binding proteins (LbpA). Here, deletion of the gene identified LbpA as an essential component of the Hdr-like sulfur-oxidizing system in the Alphaproteobacterium Hyphomicrobium denitrificans . Thus, a biological function was established for the universally conserved cofactor lipoate that is markedly different from its canonical roles in central metabolism...
July 13, 2018: ELife
https://www.readbyqxmd.com/read/29985553/flexible-assembly-of-an-enzyme-cascade-on-a-dna-triangle-prism-nanostructure-for-the-controlled-biomimetic-generation-of-nitric-oxide
#6
Li Zhou, Yu Liu, Hui Shi, Xiaohai Yang, Jin Huang, Songyang Liu, Qiaoshu Chen, Jianbo Liu, Kemin Wang
Spatial organization of multiple enzymes at specific positions for a controlled reaction cascade has attracted wide attention in recent years. Here, we report the construction of a biomimetic enzyme cascade organized on DNA triangle prism (TP) nanostructures to enable the efficient catalytic production of nitric oxide (NO) on a single microbead. Two enzymes, glucose oxidase (GOx) and horseradish peroxidase (HRP), were assembled at adjacent locations on a DNA TP nanostructure by using DNA-binding protein adaptors with small interenzyme distances...
July 9, 2018: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/29922720/biomimetic-enzyme-cascade-reaction-system-in-microfluidic-electrospray-microcapsules
#7
Huan Wang, Ze Zhao, Yuxiao Liu, Changmin Shao, Feika Bian, Yuanjin Zhao
Mimicking subcellular compartments containing enzymes in organisms is considered a promising approach to substitute for missing or lost cellular functions. Inspired by the multicompartment structures of cellular architectures, we present a novel multienzyme system based on hollow hydrogel microcapsules with flexible enzymatic inverse opal particles. Benefiting from the precise operation capability of the microfluidic electrospray and the remarkable structural color marks in the inverse opal particles, we developed a multienzyme system with controllable number, type, and spatial arrangement of the encapsulated enzymes...
June 2018: Science Advances
https://www.readbyqxmd.com/read/29899443/structural-basis-for-regulation-of-human-acetyl-coa-carboxylase
#8
Moritz Hunkeler, Anna Hagmann, Edward Stuttfeld, Mohamed Chami, Yakir Guri, Henning Stahlberg, Timm Maier
Acetyl-CoA carboxylase catalyses the ATP-dependent carboxylation of acetyl-CoA, a rate-limiting step in fatty acid biosynthesis1,2 . Eukaryotic acetyl-CoA carboxylases are large, homodimeric multienzymes. Human acetyl-CoA carboxylase occurs in two isoforms: the metabolic, cytosolic ACC1, and ACC2, which is anchored to the outer mitochondrial membrane and controls fatty acid β-oxidation1,3 . ACC1 is regulated by a complex interplay of phosphorylation, binding of allosteric regulators and protein-protein interactions, which is further linked to filament formation1,4-8 ...
June 2018: Nature
https://www.readbyqxmd.com/read/29784804/structure-of-xyloglucan-xylosyltransferase-1-reveals-simple-steric-rules-that-define-biological-patterns-of-xyloglucan-polymers
#9
Alan T Culbertson, Jacqueline J Ehrlich, Jun-Yong Choe, Richard B Honzatko, Olga A Zabotina
The plant cell wall is primarily a polysaccharide mesh of the most abundant biopolymers on earth. Although one of the richest sources of biorenewable materials, the biosynthesis of the plant polysaccharides is poorly understood. Structures of many essential plant glycosyltransferases are unknown and suitable substrates are often unavailable for in vitro analysis. The dearth of such information impedes the development of plants better suited for industrial applications. Presented here are structures of Arabidopsis xyloglucan xylosyltransferase 1 (XXT1) without ligands and in complexes with UDP and cellohexaose...
June 5, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29662082/hadd-a-novel-fatty-acid-synthase-type-ii-protein-is-essential-for-alpha-and-epoxy-mycolic-acid-biosynthesis-and-mycobacterial-fitness
#10
Cyril Lefebvre, Richard Boulon, Manuelle Ducoux, Sabine Gavalda, Françoise Laval, Stevie Jamet, Nathalie Eynard, Anne Lemassu, Kaymeuang Cam, Marie-Pierre Bousquet, Fabienne Bardou, Odile Burlet-Schiltz, Mamadou Daffé, Annaïk Quémard
Mycolic acids (MAs) have a strategic location within the mycobacterial envelope, deeply influencing its architecture and permeability, and play a determinant role in the pathogenicity of mycobacteria. The fatty acid synthase type II (FAS-II) multienzyme system is involved in their biosynthesis. A combination of pull-downs and proteomics analyses led to the discovery of a mycobacterial protein, HadD, displaying highly specific interactions with the dehydratase HadAB of FAS-II. In vitro activity assays and homology modeling showed that HadD is, like HadAB, a hot dog folded (R)-specific hydratase/dehydratase...
April 16, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29603822/manganese-based-nanozymes-multienzyme-redox-activity-and-effect-on-the-nitric-oxide-produced-by-endothelial-nitric-oxide-synthase
#11
Namrata Singh, Motika Geethika, Sandeep M Eswarappa, Govindasamy Mugesh
Nanomaterials having enzyme-like activity (nanozymes) make them suitable candidates for various biomedical applications. In this study, we demonstrate the morphology-dependent enzyme mimetic activity of Mn3 O4 nanoparticles. It is found that Mn3 O4 nanoparticles mimic the functions of all three cellular antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Interestingly, the nanozyme activity of Mn3 O4 depends on various factors including size, morphology, surface area, and the redox properties of the metal ions...
June 12, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29572992/therapeutic-nanoreactors-as-in-vivo-nanoplatforms-for-cancer-therapy
#12
REVIEW
Jean Felix Mukerabigwi, Zhishen Ge, Kazunori Kataoka
Therapeutic nanoreactors have been proposed as nanoplatforms to treat diseases through in situ production of therapeutic agents. When this treatment strategy is applied in cancer therapy, it can efficiently produce highly toxic anticancer drugs in situ from low-toxic prodrugs or some biomolecules in tumor tissues, which can maximize the therapeutic efficacy with a significantly low systemic toxicity. An ideal therapeutic nanoreactor can provide the reaction space, protect the loaded fragile catalysts, target the desired pathological site, and be selectively activated...
March 23, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29477859/bioamination-of-alkane-with-ammonium-by-an-artificially-designed-multienzyme-cascade
#13
Hui-Lei Yu, Tuo Li, Fei-Fei Chen, Xiao-Jing Luo, Aitao Li, Chao Yang, Gao-Wei Zheng, Jian-He Xu
Biocatalytic C-H amination is one of the most challenging tasks. C-H amination reaction can hardly be driven efficiently by solely one enzyme so far. Thus, enzymatic synergy represents an alternative strategy. Herein, we report an "Artificially Bioamination Pathway" for C-H amination of cyclohexane as a model substrate. Three enzymes, a monooxygenase P450BM3 mutant, an alcohol dehydrogenase ScCR from Streptomyces coelicolor and an amine dehydrogenase EsLeuDH from Exiguobacterium sibiricum, constituted a clean cascade reaction system with easy product isolation...
May 2018: Metabolic Engineering
https://www.readbyqxmd.com/read/29457453/exquisite-enzyme-fenton-biomimetic-catalysts-for-hydroxyl-radical-production-by-mimicking-an-enzyme-cascade
#14
Qi Zhang, Shuo Chen, Hua Wang, Hongtao Yu
Hydrogen peroxide (H2 O2 ) is a key reactant in the Fenton process. As a byproduct of enzymatic reaction, H2 O2 can be obtained via catalytical oxidation of glucose using glucose oxidase in the presence of O2 . Another oxidation product (gluconic acid) can suitably adjust the microenvironmental pH contributing to the Fe3+ /Fe2+ cycle in the Fenton reaction. Enzymes are extremely efficient at catalyzing a variety of reactions with high catalytic activity, substrate specificity, and yields in living organisms...
March 14, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29426820/a-mathematical-model-for-enzyme-clustering-in-glucose-metabolism
#15
Miji Jeon, Hye-Won Kang, Songon An
We have recently demonstrated that the rate-limiting enzymes in human glucose metabolism organize into cytoplasmic clusters to form a multienzyme complex, the glucosome, in at least three different sizes. Quantitative high-content imaging data support a hypothesis that the glucosome clusters regulate the direction of glucose flux between energy metabolism and building block biosynthesis in a cluster size-dependent manner. However, direct measurement of their functional contributions to cellular metabolism at subcellular levels has remained challenging...
February 9, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29408176/microwave-assisted-enzymatic-hydrolysis-of-dna-for-mass-spectrometric-analysis-a-new-strategy-for-accelerated-hydrolysis
#16
Sujatha Chilakala, Lan Li, Ye Feng, Yan Xu
Study of DNA base composition, DNA adducts and modification in its primary structure is a subject of interest in different fields of scientific research. Various methods like immunochemistry, capillary electrophoretic separation, chromatographic separation coupled with mass spectrometric (LC-MS/MS) detection have been developed for DNA analysis. During the past decade LC-MS/MS has emerged as a more sensitive and selective technique and now frequently used for the analysis of DNA. The workflow for the DNA analysis include DNA extraction, hydrolysis of DNA into mononucleosides and analysis...
April 1, 2018: Analytical Biochemistry
https://www.readbyqxmd.com/read/29223890/gold-core-ceria-shell-based-redox-active-nanozyme-mimicking-the-biological-multienzyme-complex-phenomenon
#17
Stuti Bhagat, N V Srikanth Vallabani, Vaithiyalingam Shutthanandan, Mark Bowden, Ajay S Karakoti, Sanjay Singh
Catalytically active individual gold (Au) and cerium oxide (CeO2 ) nanoparticles (NPs) are well known to exhibit specific enzyme-like activities, such as natural catalase, oxidase, superoxide dismutase, and peroxidase enzymes. These activities have been maneuvered to design several biological applications such as immunoassays, glucose detection, radiation and free radical protection and tissue engineering. In biological systems, multienzyme complexes are involved in catalyzing important reactions of essential metabolic processes such as respiration, biomolecule synthesis, and photosynthesis...
March 1, 2018: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/29209155/optimization-of-quantitative-proteomic-analysis-of-clots-generated-from-plasma-of-patients-with-venous-thromboembolism
#18
Aneta Stachowicz, Jakub Siudut, Maciej Suski, Rafał Olszanecki, Ryszard Korbut, Anetta Undas, Jacek R Wiśniewski
Background: It is well known that fibrin network binds a large variety of proteins, including inhibitors and activators of fibrinolysis, which may affect clot properties, such as stability and susceptibility to fibrinolysis. Specific plasma clot composition differs between individuals and may change in disease states. However, the plasma clot proteome has not yet been in-depth analyzed, mainly due to technical difficulty related to the presence of a highly abundant protein-fibrinogen and fibrin that forms a plasma clot...
2017: Clinical Proteomics
https://www.readbyqxmd.com/read/29115133/pursuing-the-promise-of-enzymatic-enhancement-with-nanoparticle-assemblies
#19
James Nicholas Vranish, Mario G Ancona, Scott A Walper, Igor L Medintz
The growing emphasis on green chemistry, renewable resources, synthetic biology, regio-/stereospecific chemical transformations, and nanotechnology for providing new biological products and therapeutics is reinvigorating research into enzymatic catalysis. Although the promise is profound, many complex issues remain to be addressed before this effort will have a significant impact. Prime among these is to combat the degradation of enzymes frequently seen in ex vivo formats following immobilization to stabilize the enzymes for long-term application and to find ways of enhancing their activity...
March 6, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29050588/sequential-one-pot-multienzyme-synthesis-of-hyaluronan-and-its-derivative
#20
Shuang Li, Shuaishuai Wang, Xuan Fu, Xian-Wei Liu, Peng George Wang, Junqiang Fang
Hyaluronan (HA) is a linear polysaccharide composed of repeating disaccharide units. It has been well documented to play an array of biological functions in cancer events. Here, we reported a sequential one-pot multienzyme (OPME) strategy for in vitro synthesis of HA and its derivatives. The strategy, which combined in situ sugar nucleotides generation with HA chain polymerization, could convert cheap monosaccharides into HA polymers without consuming exogenous sugar nucleotide donors. HA polymers (number-average molecular weight ranged from 1...
December 15, 2017: Carbohydrate Polymers
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