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Cryo-Em snapshots of mycobacterial arabinosyltransferase complex EmbB2-Acpm2

Protein & Cell 2020年第7期11卷 505-517页

作者： Lu Zhang Yao Zha Ruogu Gao Jun Li Xiuna Yang Yan Gao Wei Zhao Sudagar S.Gurcha Natacha Veerapen sarah m.batt Kajelle Kaur Besra Wenqing Xu Lijun Bi Xian'en Zhang Luke W.Guddat Haitao Yang Quan Wang Gurdyal S.Besra Zihe Rao State Key Laboratory of medicinal Chemical Biology College of Life Sciences and College of PharmacyNankai UniversityTianjin 300353China Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China CAS Center for Excellence in molecular Cell Science Shanghai Institute of Biochemistry and Cell BiologyChinese Academy of Sciences(CAS)Shanghai 200031China University of Chinese Academy of Sciences Beijing 100101China National Laboratory of Biomacromolecules and Key Laboratory of RNA Biology CAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsCASBeijing 100101China Laboratory of Structural Biology Tsinghua UniversityBeijing 100084China School of Biosciences Institute of Microbiology and InfectionUniversity of BirminghamBirmingham B152TTUK School of Chemistry and molecular Biosciences The University of QueenslandBrisbaneQLD 4072Australia

Inhibition of mycobacterium tuberculosis(mtb)cell wall assembly is an established strategy for anti-TB *** EmbB,which catalyzes the transfer of arabinose from the donor decaprenyl-phosphate-arabinose(DPA)to its arabinosyl acceptor is an essential enzyme for mtb cell wall *** of drug resistance mutations suggests that EmbB is the main target of the front-line anti-TB drug,***,we report the cryo-Em structures of mycobacterium smegmatis EmbB in its"resting state"and DPA-bound"active state".EmbB is a fifteen-transmembrane-spanning protein,assembled as a *** protomer has an associated acyl-carrier-protein(Acpm)on their cytoplasmic ***-mational changes upon DPA binding indicate an asym-metric movement within the EmbB dimer during *** studies have identified critical residues in substrate recognition and catalysis,and demonstrated that ethambutol inhibits transferase activity of EmbB by competing with *** structures represent the first step directed towards a rational approach for anti-TB drug discovery.

关键词： mycobacterium tuberculosis EmbB cryo-Em ethambutol cell wall synthesis arabinoglacatan arabinosyltransferase acyl-carrier-protein drug discovery

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How plants grow up

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Journal of Integrative Plant Biology 2019年第3期61卷 257-277页

作者： sarah m mcKim Division of Plant Sciences University of Dundee at The James Hutton Institute

A plant's lateral structures, such as leaves,branches and flowers, literally hinge on the shoot axis,making its integrity and growth fundamental to plant *** all plants, subapical proliferation within the shoot tip displaces cells downward to extrude the cylindrical *** the transition to flowering, many plants show extensive axial elongation associated with increased subapical proliferation and expansion. However, the cereal grasses also elongate their stems, called culms, due to activity within detached intercalary meristems which displaces cells upward, elevating the grain-bearing inflorescence. Variation in culm length within species is especially relevant to cereal crops, as demonstrated by the high-yielding semi-dwarfed cereals of the Green Revolution. Although previously understudied, recent renewed interest the regulation of subapical and intercalary growth suggests that control of cell division planes,boundary formation and temporal dynamics of differentiation, are likely critical mechanisms coordinating axial growth and development in plants.

关键词： plants grow up^FA lateral structures

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Release of Arabinose from Wheat Insoluble Arabinoxylan by the Action of α-L-Arabinofuranosidase in Synergism with Endo-Xylanases

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Advances in Enzyme Research 2023年第4期11卷 147-153页

作者： Dominic W. S. Wong sarah batt Western Regional Research Center United States Department of Agriculture Agricultural Research Service Albany CA USA

Wheat arabinoxylan (water-insoluble fraction) contains ~36% arabinose which may include both singly or doubly substitutions at C2/C3 of the Xylp units. α-L-Arabinofuranosidses (ABFs) of two GH families were analyzed for their respective activities on the hydrolysis of Xylp-Araf. BaABF (GH43) produced twice the yield of arabinose residues from the heteroxylan compared to AnABF (GH51) under the same reaction conditions. Two endo-xylanases (of GH10 and 11) also showed differential hydrolytic activities on the Xylp chain, with the GH10 XYN-ATm double the amount of reducing sugar yield (as xylose equivalent) than using the GH11 XYN-m3. When the ABF and XYN were combined in optimial ratios, a synergistic increase of 73.8% in arabinose yield was observed.

关键词： α-L-Arabinofuranosidase mono-Substituted Xylopyranosyl Residuet Di-Substituted Xylopyranosyl Unit Arabinoxylan Arabinofuranohydrolase (AXH)

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Cloning of an α-L-Arabinofuranosidase and Characterization of Its Action on mono- and Di-Substituted Xylopyranosyl Units

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Advances in Enzyme Research 2022年第4期10卷 75-82页

作者： Dominic W. S. Wong sarah batt United States Department of Agriculture Agricultural Research Service Western Regional Research Center Albany CA USA

An α-L-arabinofuranosidase (ARF) gene of 1503 bp was synthesized, subcloned into pET26b vector, and expressed in Escherichia coli. The enzyme was purified in active form, and consisted of 500 amino acid residues, corresponding to 55 kD based on SDS-PAGE. The affinity-purified protein was characterized using arabinofuranosyl xylooligosaccharides (AXOS) as substrates. The pH effect was investigated showing an optimum at pH 5.5. XaARF catalyzed the cleavage of arabinose at C3 of the xylopyranosyl unit efficiently if the arabinofuranosyl substitution was at the terminal compared to internal xylose units. The enzyme was able to act on di-substituted xylopyranosyl units with the first cleavage at C3 followed by C2 linkages.

关键词： α-L-Arabinofuranosidase mono-Substituted Xylopyranosyl Unit Di-Substituted Xylopyranosyl Unit Arabinofuranosyl Xylooligosaccharides (AXOS)

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Comprehension of functional support by enculturated chimpanzees Pan troglodytes

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Current Zoology 2011年第4期57卷 429-440页

作者： Anna m. YOCOm sarah T. BOYSEN Department of Psychology The Ohio State University Columbus OH 43210 USA

Studies of causal understanding of tool relationships in captive chimpanzees have yielded disparate findings, particularly those reported by Povinelli ＆ colleagues （2000） for tool tasks by laboratory chimpanzees. The present set of experiments tested nine enculturated chimpanzees on three versions of a support task, as described by Povinelli （2000）, during which food re- wards were presented in different experimental configurations. In Experiment 1, stimulus pairs included a choice between a cloth with a reward on the upper right comer or with a second reward off the cloth, adjacent to a comer, with the second pair comprised of a cloth with food on the upper right comer, and a second cloth with the reward on the substrate, partially covered. All subjects were successful with both test conditions in Experiment 1. In a second study, the experimental choices included one of two possi- ble correct options, paired with one of three incorrect options, with the three incorrect choices all involving varying degrees of perceptual containment. All nine chimpanzees scored significantly above chance across all six conditions. In Experiment 3, four unique conditions were presented, combining one of two possible correct choices with one of two incorrect choices. Six of the subjects scored significantly above chance across the four conditions, and group performance on individual conditions was also significant. Superior performance was demonstrated by female subjects in Experiment 3, similar to sex differences in tool use previously reported for wild chimpanzees and some tool tasks in captive chimpanzees. The present results for Experiments 2 ＆ 3 were significantly differed from those reported by Povinelli et al. （2000） for laboratory-born, peer-reared chimpanzees. One contribution towards the dramatic differences between the two study populations may be the significant rearing and housing differences of the chimpanzee groups. One explanation is that under conditions of enculturat

关键词： Chimpanzees Comparative cognition Tool use Causality

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metabolite Transporter Regulation of ABA Function and Guard Cell Response

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molecular Plant 2014年第10期7卷 1505-1507页

作者： Yunqing Yu sarah m. Assmann Biology Department Pennsylvania State University 208 Mueller Laboratory University Park PA 16802–5301 USA

Pairs of guard cells form stomatal pores through which gas exchange occurs. Gas exchange includes transpirational water loss, and guard cell signaling in drought response has been studied for decades. Abscisic acid （ABA） is the major hormone that regulates drought responses. ABA and other metabolites can be synthesized in one cell type or subcellular compartment and transported across mem- branes by specific transporters to conduct biological func- tions. Two new papers, both taking advantage of reverse genetic methods, one focusing on a plasma membrane ABA efflux carrier （Zhang et al., 2014） and the other on a putative mitochondrial pyruvate carrier （Li et al., 2014）, have recently shown the importance of metabolite trans- porters in ABA function and guard cell response.

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Combinatorial Enzyme Approach for Production and Screening of Libraries of Feruloyl Oligosaccharides

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Advances in Enzyme Research 2020年第3期8卷 27-37页

作者： Dominic W. S. Wong sarah batt William Orts Western Regional Research Center USDA-ARS Albany CA USA

Combinatorial chemistry involves the chemical or biological synthesis of diverse variation of the structures of a target molecule and the library is then screened for variants of desirable target properties. The approach has been a focus of research activity in drug discovery and biotechnology. This report is to demonstrate the application of enzyme technology using the concept of combinatorial chemistry as a novel approach for the bioconversion of plant fibers. Wheat insoluble fiber was subjected to combinatorial enzyme digestion to create structural variants of feruloyl oligosaccharides (FOS). Fractionation and screening resulted in the isolation of a fraction of bioactive FOS species showing antimicrobial activity. These results demonstrate the feasibility and usefulness of the combinatorial enzyme technique in the transformation of plant biomass to value-added products.

关键词： Combinatorial Enzyme Wheat Insoluble Arabinoxylan Feruloyl Oligosaccharides Endo-Xylanase α-L-Arabinoxylanosidase

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Combinatorial Enzyme Approach to Convert Wheat Insoluble Arabinoxylan to Bioactive Oligosaccharides

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Advances in Enzyme Research 2023年第1期11卷 1-10页

作者： Dominic W. S. Wong sarah batt William H. Orts Western Regional Research Center United States Department of Agriculture Agricultural Research Service Albany CA USA

Combinatorial enzyme technology was applied for the conversion of wheat insoluble arabinoxylan to oligosaccharide structural variants. The digestive products were fractionated by Bio-Gel P4 column and screened for bioactivity. One fraction pool was observed to exhibit antimicrobial property resulting in the suppression of cell growth of the test organism ATCC 8739 E. coli. It has a mIC value of 1.5% (w/v, 35°C, 20 hr) and could be useful as a new source of prebiotics or preservatives. The present results further confirm the science and useful application of combinatorial enzyme approach.

关键词： Combinatorial Enzyme Approach Wheat Insoluble Arabinoxylan Bioactive Oligosaccharides

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microbial community coalescence and nitrogen cycling in simulated mortality decomposition hotspots

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Ecological Processes 2023年第1期12卷 608-624页

作者： sarah W.Keenan Alexandra L.Emmons Jennifer m.DeBruyn Department of Geology and Geological Engineering South Dakota School of Mines and Technology501 East St.Joseph StreetRapidSD 57701USA Department of Anthropology University of TennesseeKnoxvilleTNUSA Department of Biosystems Engineering and Soil Science University of Tennessee2506 E.J.Chapman DriveKnoxvilleTN 37996USA

Background The pulsed introduction of dead plant and animal material into soils represents one of the primary mechanisms for returning organic carbon(C)and nitrogen(N)compounds to biogeochemical *** of animal carcasses provides a high C and N resource that stimulates indigenous environmental microbial communities and introduces non-indigenous,carcass-derived microbes to the ***,the dynamics of the coalesced microbial communities,and the relative contributions of environment-and carcass-derived microbes to C and N cycling are *** test whether environment-derived,carcass-derived,or the combined microbial communities exhibited a greater influence on C and N cycling,we conducted controlled laboratory experiments that combined carcass decomposition fluids and soils to simulate carcass decomposition *** selectively sterilized the decomposition fluid and/or soil to remove microbial communities and create different combinations of environment-and carcass-derived communities and incubated the treatments under three temperatures(10,20,and 30℃).Results Carcass-derived bacteria persisted in soils in our simulated decomposition scenarios,albeit at low *** communities had higher respiration rates at 10 and 30℃ compared to soil or carcass communities ***,at higher temperatures,mixed communities had reduced diversity,but higher respiration,suggesting functional *** communities treatments also provided evidence that carcass-associated microbes may be contributing to ammonification and denitrification,but that nitrification is still primarily carried out by native soil *** Our work yields insight into the dynamics of microbial communities that are coalescing during carcass decomposition,and how they contribute to recycling carcasses in terrestrial ecosystems.

关键词： Carcass decomposition microcosm Nitrogen Carbon Biogeochemical cycling Coalescence

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Combinatorial Enzyme Approach to Produce Oligosaccharides of Diverse Structures for Functional Screen

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Advances in Enzyme Research 2018年第2期6卷 11-20页

作者： Dominic W. S. Wong Doris Feng, sarah batt William Orts Western Regional Research Center USDA-ARS Albany CA USA

Combinatorial chemistry has been a focus of research activity in modern drug discovery and biotechnology. It is a concept by which a vast library of molecular diversity is synthesized and screened for target properties. This report is to illustrate the application of enzyme technology using the concept of combinatorial chemistry as a novel approach for the bioconversion of plant fibers. Citrus pectin was subjected to combinatorial enzyme digestion to create libraries of pectic oligosaccharides with diverse structural variants. Repeated cycles of fractionation and screening resulted in the isolation and identification of an active oligoGalA species with antimicrobial activity.

关键词： Combinatorial Enzyme Polygalacturonase Pectate Lyase Pectin Oligosaccharides

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