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https://www.readbyqxmd.com/read/29208763/characterization-of-the-catalytic-signature-of-scabin-toxin-a-dna-targeting-adp-ribosyltransferase
#1
Bronwyn Lyons, Miguel R Lugo, Stephanie Carlin, Taylor Lidster, A Rod Merrill
Scabin was previously identified as a novel DNA-targeting mono-ADP-ribosyltransferase toxin from the plant pathogen 87.22 strain of Streptomyces scabies Scabin is a member of the Pierisin-like subgroup of mono-ADP-ribosyltransferase toxins, since it targets DNA. An in-depth characterization of both the glycohydrolase and transferase enzymatic activities of Scabin was conducted. Several protein variants were developed based on an initial Scabin·DNA molecular model. Consequently, three residues were deemed important for DNA binding and transferase activity...
December 5, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/29189732/identification-and-characterization-of-hyphantria-cunea-aminopeptidase-n-as-a-binding-protein-of-bacillus-thuringiensis-cry1ab35-toxin
#2
Yakun Zhang, Dan Zhao, Xiaoping Yan, Wei Guo, Yajun Bao, Wei Wang, Xiaoyun Wang
The fall webworm, Hyphantria cunea (Drury) is a major invasive pest in China. Aminopeptidase N (APN) isoforms in lepidopteran larvae midguts are known for their involvement in the mode of action of insecticidal crystal (Cry) proteins from Bacillus thuringiensis. In the present work, we identified a putative Cry1Ab toxin-binding protein, an APN isoform designated HcAPN3, in the midgut of H. cunea by ligand blot and mass spectrometry. HcAPN3 was highly expressed throughout all larval developmental stages and was abundant in the midgut and hindgut tissues...
November 30, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29158482/structural-basis-for-the-unique-ganglioside-and-cell-membrane-recognition-mechanism-of-botulinum-neurotoxin-dc
#3
Sicai Zhang, Ronnie P-A Berntsson, William H Tepp, Liang Tao, Eric A Johnson, Pål Stenmark, Min Dong
Botulinum neurotoxins (BoNTs), the most potent toxins known, are potential bioterrorism agents. It is well established that all seven serotypes of BoNTs (BoNT/A-G) require complex gangliosides as co-receptors. Here, we report that BoNT/DC, a presumed mosaic toxin between BoNT/D and BoNT/C1, binds and enters efficiently into neurons lacking complex gangliosides and shows no reduction in toxicity in mice deficient in complex gangliosides. The co-crystal structure of BoNT/DC with sialyl-Thomsen-Friedenreich antigen (Sialyl-T) suggests that BoNT/DC recognizes only the sialic acid, but not other moieties in gangliosides...
November 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/29133347/analysis-of-the-human-mucosal-response-to-cholera-reveals-sustained-activation-of-innate-immune-signaling-pathways
#4
Daniel L Bourque, Taufiqur Rahman Bhuiyan, Diane P Genereux, Rasheduzzaman Rashu, Crystal N Ellis, Fahima Chowdhury, Ashraful I Khan, Nur Haq Alam, Anik Paul Lazina Hossain, Leslie M Mayo-Smith, Richelle C Charles, Ana A Weil, Regina C LaRocque, Stephen B Calderwood, Edward T Ryan, Elinor K Karlsson, Firdausi Qadri, Jason B Harris
To better understand the innate immune response to Vibrio cholerae infection, we tracked gene expression in the duodenal mucosa of eleven Bangladeshi adults with cholera, using biopsies obtained immediately after rehydration and at 30 and 180 days later. We identified differentially expressed genes and performed an analysis to predict differentially regulated pathways and upstream regulators. During acute cholera, there was a broad increase in the expression of genes associated with innate immunity, including activation of the NF-κB, MAPK, and TLR-mediated signaling pathways, which unexpectedly persisted even 30 days after infection...
November 13, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/29124866/characterization-of-the-toxin-plx2a-a-rhoa-targeting-adp-ribosyltransferase-produced-by-the-honey-bee-pathogen-paenibacillus-larvae
#5
Julia Ebeling, Anne Fünfhaus, Henriette Knispel, Dan Krska, Ravikiran Ravulapalli, Kayla A Heney, Miguel R Lugo, A Rod Merrill, Elke Genersch
The toxin Plx2A is an important virulence factor of Paenibacillus larvae, the etiological agent of American Foulbrood, the most destructive bacterial disease of honey bees. Biochemical and functional analyses as well as the crystal structure of Plx2A revealed that it belongs to the C3 mono-ADP-ribosylating toxin subgroup. RhoA was identified as the cellular target of Plx2A activity. The kinetic parameters (KM, kcat) were established for both the transferase and glycohydrolase (GH) reactions. When expressed in yeast, Plx2A was cytotoxic for eukaryotic cells and catalytic variants confirmed that the cytotoxicity of Plx2A depends on its enzymatic activity...
November 10, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/29111354/three-gpi-anchored-alkaline-phosphatases-are-involved-in-the-intoxication-of-cry1ca-toxin-to-spodoptera-exigua-larvae
#6
Xiang-Liang Ren, Hong-Yan Hu, Wei-Li Jiang, Xiao-Yan Ma, Ya-Jie Ma, Guo-Qing Li, Yan Ma
Glycosylphosphatidylinositol (GPI)-anchored alkaline phosphatase (ALP) isoforms are crucial for the intoxication of crystal proteins (Cry) to several insect species. We cloned five SeALPs from the larval midgut of Spodoptera exigua, a major pest of many crops. All five SeALPs contain a signal peptide at the N-terminus, a phosphatase domain, and a GPI-anchor site at the C-terminus. Additionally, the sequences encode two or three potential N-glycosylation sites. The five SeALPs were highly expressed at the larval stage, especially in the larval gut or Malpighian tubules...
October 27, 2017: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/29074967/a-proteomic-analysis-provides-novel-insights-into-the-stress-responses-of-caenorhabditis-elegans-towards-nematicidal-cry6a-toxin-from-bacillus-thuringiensis
#7
Bing Wang, Haiwen Wang, Jing Xiong, Qiaoni Zhou, Huan Wu, Liqiu Xia, Lin Li, Ziquan Yu
Cry6A represents a novel family of nematicidal crystal proteins from Bacillus thuringiensis. It has distinctive architecture as well as mechanism of action from Cry5B, a highly focused family of nematicidal crystal proteins, and even from other insecticidal crystal proteins containing the conserved three-domain. However, how nematode defends against Cry6A toxin remains obscure. In this study, the global defense pattern of Caenorhabditis elegans against Cry6Aa2 toxin was investigated by proteomic analysis. In response to Cry6Aa2, 12 proteins with significantly altered abundances were observed from worms, participating in innate immune defense, insulin-like receptor (ILR) signaling pathway, energy metabolism, and muscle assembly...
October 26, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29061301/stoichiometry-and-mechanistic-implications-of-the-macab-tolc-tripartite-efflux-pump
#8
Inseong Jo, Seokho Hong, Minho Lee, Saemee Song, Jin-Sik Kim, Alok K Mitra, Jaekyung Hyun, Kangseok Lee, Nam-Chul Ha
The MacAB-TolC tripartite efflux pump is involved in resistance to macrolide antibiotics and secretion of protein toxins in many Gram-negative bacteria. The pump spans the entire cell envelope and operates by expelling substances to extracellular space. X-ray crystal and electron microscopic structures have revealed the funnel-like MacA hexamer in the periplasmic space and the cylindrical TolC trimer. Nonetheless, the inner membrane transporter MacB still remains ambiguous in terms of its oligomeric state in the functional complex...
October 20, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29027367/the-parasporal-crystals-of-bacillus-pumilus-strain-15-1-a-potential-virulence-factor
#9
Diana C Garcia-Ramon, Colin Berry, Carmen Tse, Alberto Fernández-Fernández, Antonio Osuna, Susana Vílchez
Bacillus pumilus strain 15.1 was previously found to cause larval mortality in the Med-fly Ceratitis capitata and was shown to produce crystals in association with the spore. As parasporal crystals are well-known as invertebrate-active toxins in entomopathogenic bacteria such as Bacillus thuringiensis (Cry and Cyt toxins) and Lysinibacillus sphaericus (Bin and Cry toxins), the B. pumilus crystals were characterized. The crystals were composed of a 45 kDa protein that was identified as an oxalate decarboxylase by peptide mass fingerprinting, N-terminal sequencing and by comparison with the genome sequence of strain 15...
October 12, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/29019656/adsorption-of-insecticidal-crystal-protein-cry11aa-onto-nano-mg-oh-2-effects-on-bioactivity-and-anti-ultraviolet-ability
#10
Xiaohong Pan, Zhangyan Xu, Lan Li, Enshi Shao, Saili Chen, Tengzhou Huang, Zhi Chen, Wenhua Rao, Tianpei Huang, Lingling Zhang, Songqing Wu, Xiong Guan
The traditional Bacillus thuringiensis (Bt) formulations for field applications are not resistant to harsh environmental conditions. Hence, the active ingredients of the Bt bioinsecticides could degrade quickly and has low anti-ultraviolet ability in the field, which significantly limits its practical application. In the present study, we developed an efficient and stable delivery system for Bt Cry11Aa toxins. We coated Cry11Aa proteins with Mg(OH)2 nanoparticles (MHNPs), and then assessed the effects of MHNPs on bioactivity and anti-ultraviolet ability of the Cry11Aa proteins...
October 23, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29018619/alpha-arylphorin-is-a-mitogen-in-the-heliothis-virescens-midgut-cell-secretome-upon-cry1ac-intoxication
#11
Anais Castagnola, Jerreme Jackson, Omaththage P Perera, Cris Oppert, Shigetoshi Eda, Juan Luis Jurat-Fuentes
Insecticidal crystal (Cry) proteins produced by the bacterium Bacillus thuringiensis (Bt) target cells in the midgut epithelium of susceptible larvae. While the mode of action of Cry toxins has been extensively investigated, the midgut response to Cry intoxication and its regulation are not well characterized. In this work, we describe the secreted proteome (secretome) of primary mature midgut cell cultures from Heliothis virescens larvae after exposure to Cry1Ac toxin compared to control buffer treatment. The Cry1Ac-induced secretome caused higher proliferation and differentiation and an overall reduction in total cell mortality over time in primary H...
2017: PeerJ
https://www.readbyqxmd.com/read/28986943/crystal-structure-of-mycobacterium-tuberculosis-vapc20-toxin-and-its-interactions-with-cognate-antitoxin-vapb20-suggest-a-model-for-toxin-antitoxin-assembly
#12
Amar Deep, Soni Kaundal, Sakshi Agarwal, Ramandeep Singh, Krishan Gopal Thakur
VapBCs, virulence-associated proteins, are the most abundant type II toxin-antitoxin (TA) systems in prokaryotes. Under normal conditions, toxin and antitoxin interact to form a heterooctameric complex, which upon binding to operator sites, inhibits their own expression. Under stress conditions, the VapB antitoxin is degraded by cellular proteases to release a free VapC toxin, which in turn inhibits cell growth mainly by targeting protein translation. However, the intermediate steps involved in the assembly of the heterooctameric complex have not been resolved...
October 7, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28979890/structure-based-prototype-peptides-targeting-the-pseudomonas-aeruginosa-type-vi-secretion-system-effector-as-a-novel-antibacterial-strategy
#13
Xiaopan Gao, Zhixia Mu, Bo Qin, Yicheng Sun, Sheng Cui
The type VI secretion system (T6SS) secretes numerous toxins for bacteria-bacteria competition. TplE is a newly identified trans-kingdom toxin secreted by the T6SS in Pseudomonas aeruginosa, while TplEi neutralizes the toxic effect of TplE to protect bacteria autointoxication. Blocking the interaction of TplE-TplEi could unleash the toxin, causing bacterial cell death. In this study, we applied a crystallographic approach to design a structural-based antimicrobial peptides targeting the interaction of TplE and TplEi...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28970335/fusicoccin-activates-kat1-channels-by-stabilizing-their-interaction-with-14-3-3-proteins
#14
Andrea Saponaro, Alessandro Porro, Antonio Chaves-Sanjuan, Marco Nardini, Oliver Rauh, Gerhard Thiel, Anna Moroni
Plants acquire potassium (K+) ions for cell growth and movement via regulated diffusion through K+ channels. Here we present crystallographic and functional data showing that the K+ inward rectifier KAT1 channel is regulated by 14-3-3 proteins and further modulated by the phytotoxin fusicoccin, in analogy to the H+-ATPase. We identified a 14-3-3 mode III binding site at the very C-terminus of KAT1 and co-crystallized it with tobacco 14-3-3 proteins to describe the protein complex at atomic detail. Validation of this interaction by electrophysiology shows that 14-3-3 binding augments KAT1 conductance by increasing the maximal current and by positively shifting the voltage-dependency of gating...
September 29, 2017: Plant Cell
https://www.readbyqxmd.com/read/28959866/-interaction-of-aminopeptidase-bmapn5-and-parasporal-crystal-pc-toxin-isolated-from-bacillus-bombysepticus
#15
Jianfeng Fu, Ping Lin, Tieshan Feng, Dong Cheng, Quan Zhang, Qingyou Xia, Tingcai Cheng
Aminopeptidase N (APN) belonging to zinc-dependent metalloproteinase, not only catalyzes protein proteolytic process, but also is involved in the pathogenic process as the receptor of pathogenic toxin. In Bombyx mori, APN gene family consists of 16 members, of which BmAPN4 binds trypsin-activated parasporal crystal (PC) toxin isolated from Bacillus bombysepticus (Bb). In order to verify whether or not other APNs interact with PC toxin during the pathogenesis of Bb, we cloned BmAPN5, a member of aminopeptidase family, from the silkworm midgut...
January 25, 2017: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
https://www.readbyqxmd.com/read/28958150/synthesis-and-characterization-of-tethered-lipid-assemblies-for-membrane-protein-reconstitution-review
#16
Rémi Veneziano, Claire Rossi, Alexandre Chenal, Catherine Brenner, Daniel Ladant, Joël Chopineau
Biological membranes and their related molecular mechanisms are essential for all living organisms. Membranes host numerous proteins and are responsible for the exchange of molecules and ions, cell signaling, and cell compartmentation. Indeed, the plasma membrane delimits the intracellular compartment from the extracellular environment and intracellular membranes. Biological membranes also play a major role in metabolism regulation and cellular physiology (e.g., mitochondrial membranes). The elaboration of membrane based biomimetic systems allows us to reconstitute and investigate, in controlled conditions, biological events occurring at the membrane interface...
September 28, 2017: Biointerphases
https://www.readbyqxmd.com/read/28940938/downregulation-of-chilo-suppressalis-alkaline-phosphatase-genes-associated-with-resistance-to-three-transgenic-bacillus-thuringiensis-rice-lines
#17
L Qiu, P Wang, T Wu, B Li, X Wang, C Lei, Y Lin, J Zhao, W Ma
Insecticidal crystal (Cry) proteins produced by the bacterium Bacillus thuringiensis are highly toxic to lepidopteran pests. Strains of transgenic rice expressing cry genes have been developed that are resistant to rice pests. Understanding the mode of action of Cry toxins in rice pests will improve our ability to use them effectively as insecticides. In this study, we tested the hypothesis that alkaline phosphatases (ALPs) are involved in Cry1A, Cry2Aa and Cry1Ca toxicity in Chilo suppressalis, an important insect pest of rice crops in China...
September 21, 2017: Insect Molecular Biology
https://www.readbyqxmd.com/read/28930630/assessing-the-structure-and-stability-of-transmembrane-oligomeric-intermediates-of-an-%C3%AE-helical-toxin
#18
Rajat Desikan, Prabal K Maiti, K Ganapathy Ayappa
Protein membrane interactions play an important role in our understanding of diverse phenomena ranging from membrane-assisted protein aggregation to oligomerization and folding. Pore-forming toxins (PFTs) are the primary vehicle for infection by several strains of bacteria. These proteins which are expressed in a water-soluble form (monomers) bind to the target membrane and conformationally transform (protomers) and self-assemble to form a multimer transmembrane pore complex through a process of oligomerization...
October 3, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28901209/the-distinct-properties-of-natural-and-gm-cry-insecticidal-proteins
#19
Jonathan R Latham, Madeleine Love, Angelika Hilbeck
The Cry toxins are a family of crystal-forming proteins produced by the bacterium Bacillus thuringiensis. Their mode of action is thought to be to create pores that disrupt the gut epithelial membranes of juvenile insects. These pores allow pathogen entry into the hemocoel, thereby killing the insect. Genes encoding a spectrum of Cry toxins, including Cry mutants, Cry chimaeras and other Cry derivatives, are used commercially to enhance insect resistance in genetically modified (GM) crops. In most countries of the world, such GM crops are regulated and must be assessed for human and environmental safety...
September 13, 2017: Biotechnology & Genetic Engineering Reviews
https://www.readbyqxmd.com/read/28880078/the-role-of-disulfide-bond-replacements-in-analogues-of-the-tarantula-toxin-protx-ii-and-their-effects-on-inhibition-of-the-voltage-gated-sodium-ion-channel-nav1-7
#20
Zoë V F Wright, Stephen McCarthy, Rachael Dickman, Francis E Reyes, Silvia Sanchez-Martinez, Adam Cryar, Ian Kilford, Adrian Hall, Andrew K Takle, Maya Topf, Tamir Gonen, Konstantinos Thalassinos, Alethea B Tabor
Spider venom toxins, such as Protoxin-II (ProTx-II), have recently received much attention as selective Nav1.7 channel blockers, with potential to be developed as leads for the treatment of chronic nocioceptive pain. ProTx-II is a 30-amino acid peptide with three disulfide bonds that has been reported to adopt a well-defined inhibitory cystine knot (ICK) scaffold structure. Potential drawbacks with such peptides include poor pharmacodynamics and potential scrambling of the disulfide bonds in vivo. In order to address these issues, in the present study we report the solid-phase synthesis of lanthionine-bridged analogues of ProTx-II, in which one of the three disulfide bridges is replaced with a thioether linkage, and evaluate the biological properties of these analogues...
September 20, 2017: Journal of the American Chemical Society
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