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Tetramer

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https://www.readbyqxmd.com/read/28527888/tetrameric-structure-of-the-flagellar-cap-protein-flid-from-serratia-marcescens
#1
So Yeon Cho, Wan Seok Song, Ho Jeong Hong, Geun-Shik Lee, Seung Goo Kang, Hyun-Jeong Ko, Pyeung-Hyeun Kim, Sung-Il Yoon
Bacterial motility is provided by the flagellum. FliD is located at the distal end of the flagellum and plays a key role in the insertion of each flagellin protein at the growing tip of the flagellar filament. Because FliD functions as an oligomer, the determination of the oligomeric state of FliD is critical to understanding the molecular mechanism of FliD-mediated flagellar growth. FliD has been shown to adopt a pentameric or a hexameric structure depending on the bacterial species. Here, we report another distinct oligomeric form of FliD based on structural and biochemical studies...
May 17, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28527457/role-of-quantum-coherence-in-shaping-the-line-shape-of-an-exciton-interacting-with-a-spatially-and-temporally-correlated-bath
#2
Rajesh Dutta, Kaushik Bagchi, Biman Bagchi
Kubo's fluctuation theory of line shape forms the backbone of our understanding of optical and vibrational line shapes, through such concepts as static heterogeneity and motional narrowing. However, the theory does not properly address the effects of quantum coherences on optical line shape, especially in extended systems where a large number of eigenstates are present. In this work, we study the line shape of an exciton in a one-dimensional lattice consisting of regularly placed and equally separated optical two level systems...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28526680/decrease-in-numbers-of-naive-and-resting-b-cells-in-hiv-infected-kenyan-adults-leads-to-a-proportional-increase-in-total-and-plasmodium-falciparum-specific-atypical-memory-b-cells
#3
Anne E Frosch, Oludare A Odumade, Justin J Taylor, Kathleen Ireland, George Ayodo, Bartholomew Ondigo, David L Narum, John Vulule, Chandy C John
Human immunodeficiency virus type 1 (HIV-1) infection is associated with B cell activation and exhaustion, and hypergammaglobulinemia. How these changes influence B cell responses to coinfections such as malaria is poorly understood. To address this, we compared B cell phenotypes and Abs specific for the Plasmodium falciparum vaccine candidate apical membrane Ag-1 (AMA1) in HIV-infected and uninfected adults living in Kenya. Surprisingly, HIV-1 infection was not associated with a difference in serum AMA1-specific Ab levels...
May 19, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28523739/mechanisms-of-peptide-sex-pheromone-regulation-of-conjugation-in-enterococcus-faecalis
#4
Yuqing Chen, Arpan Bandyopadhyay, Briana K Kozlowicz, Heather A H Haemig, Albert Tai, Wei-Shou Hu, Gary M Dunny
In many gram positive bacteria, horizontal transfer and virulence are regulated by peptide-mediated cell-cell signaling. The heptapeptide cCF10 (C) activates conjugative transfer of the Enterococcus faecalis plasmid pCF10, whereas the iCF10 (I) peptide inhibits transfer. Both peptides bind to the same domain of the master transcription regulator PrgX, a repressor of transcription of the prgQ operon encoding conjugation genes. We show that repression of prgQ by PrgX tetramers requires formation of a pCF10 DNA loop where each of two PrgX DNA-binding sites is occupied by a dimer...
May 19, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28514654/crystal-structure-of-tetrameric-arabidopsis-myc2-reveals-the-mechanism-of-enhanced-interaction-with-dna
#5
Teng-Fei Lian, Yong-Ping Xu, Lan-Fen Li, Xiao-Dong Su
Jasmonates (JAs) are essential plant hormones that play important roles in the regulation of plant growth and the response to environmental stress. In the JA signaling pathway, the core transcription factors are a class of basic helix-loop-helix (bHLH) proteins, including MYC2, MYC3, and MYC4, that have different regulatory capacities. Here, we report the 2.7 Å crystal structure of the MYC2 bHLH domain complexed with G-box DNA, showing a cis-tetrameric structure. Biochemical assays confirmed that full-length MYC2 forms a stable homo-tetramer both in solution and in DNA-bound states, whereas MYC3 forms only a homodimer...
May 16, 2017: Cell Reports
https://www.readbyqxmd.com/read/28514507/hydrogen-bond-involving-cavity-nh-protons-drives-supramolecular-oligomerization-of-amido-corroles
#6
Daniel T Gryko, Rafał Orłowski, Mariusz Tasior, Barbara Ventura, Olga Staszewska-Krajewska, Wojciech Schilf, Michał Cyrański, Łukasz Dobrzycki
Trans-A2B-Corroles with amide substituents at different positions versus the macrocyclic core have been synthesized. Their self-organizing properties have been comprehensively evaluated both in solid-state and in solution. The rigid arrangement of the amide functionality with the corrole ring led to the formation of strong intramolecular interactions and precluded intermolecular interactions. Replacement of sterically hindered C6F5 substituents at positions 5 and 15 with smaller electron-withdrawing CO2Me groups resulted in significant changes in the self-assembly pattern...
May 17, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28512574/crystallographic-and-saxs-studies-of-s-adenosyl-l-homocysteine-hydrolase-from-bradyrhizobium-elkanii
#7
Tomasz Manszewski, Kamil Szpotkowski, Mariusz Jaskolski
S-Adenosyl-l-homocysteine hydrolase (SAHase) from the symbiotic bacterium Bradyrhizobium elkanii (BeSAHase) was crystallized in four ligand complexes with (i) mixed adenosine (Ado) and cordycepin (Cord; 3'-deoxyadenosine), (ii) adenine (Ade), (iii) Ado and (iv) mixed 2'-deoxyadenosine (2'-dAdo) and Ade. The crystal structures were solved at resolutions of 1.84, 1.95, 1.95 and 1.54 Å, respectively. Only the Ade complex crystallized with a dimer in the asymmetric unit, while all of the other complexes formed a crystallographically independent tetrameric assembly...
May 1, 2017: IUCrJ
https://www.readbyqxmd.com/read/28507200/effects-of-microvirin-mono-and-oligomers-on-hepatitis-c-virus
#8
Yuan Qin Min, Xu Chu Duan, Yi Dan Zhou, Anna Kulinich, Meng Wang, Zhi-Peng Cai, Hong Yu Ma, Li Liu, Xiao Lian Zhang, Josef Voglmeir
Microvirin is a carbohydrate binding protein which shows high specificity for high-mannose type N-glycan structures. In this study we tried to identify whether microvirin could bind to high-mannose containing Hepatitis C Virus (HCV) envelope glycoproteins, which are heavily decorated decorated high-mannose glycans. In addition, recombinantly expressed microvirin oligomers in di-, tri-, and tetrameric form were evaluated for their viral inhibition. Microvirin oligomers bound more efficiently to HCV virions, and displayed in comparison to the microvirin monomer a higher neutralisation potency against HCV infection...
May 15, 2017: Bioscience Reports
https://www.readbyqxmd.com/read/28505453/adaptive-and-specific-recognition-of-telomeric-g-quadruplexes-via-polyvalency-induced-unstacking-of-binding-units
#9
Jibin Abraham Punnoose, Yue Ma, Yuanyuan Li, Mai Sakuma, Shankar Mandal, Kazuo Nagasawa, Hanbin Mao
Targeting DNA G-quadruplexes using small-molecule ligands has shown to modulate biological functions mediated by G-quadruplexes inside cells. Given >716,000 G-quadruplex hosting sites in human genome, the specific binding of ligands to quadruplex becomes problematic. Here, we innovated a polyvalency based mechanism to specifically target multiple telomeric G-quadruplexes. We synthesized a tetrameric telomestatin derivative and evaluated its complex polyvalent binding with multiple G-quadruplexes by single-molecule mechanical unfolding in laser tweezers...
May 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28499947/effect-of-chemical-denaturants-on-the-conformational-stability-of-gyrb-subunit-of-dna-gyrase-from-salmonella-enterica-serovar-typhi
#10
Deepali Gupta, Ekta Sachdeva, Md Anzarul Haque, Safikur Rahman, Rohit Bansal, Abdul S Ethayathulla, Md Imtaiyaz Hassan, Punit Kaur
DNA gyrase, a type II topoisomerase maintains the topology of DNA by introducing negative supercoils using energy generated by ATP hydrolysis. It is composed of two subunits, GyrA and GyrB (GyrA2GyrB2 hetero-tetramer). GyrB comprises two domains, a 43kDa amino N-terminus (GBNTD) and 47kDa carboxyl C- terminus (GBCTD). Till now no study has been reported in terms of stability of Gyrase B and its domains using chemical denaturants related to its function. To understand the role of each domain in GyrB subunit, we estimated the thermodynamic stability of GBF and its individual domains using urea and GdmCl...
May 9, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28499769/structure-biochemical-and-kinetic-properties-of-recombinant-pst2p-from-saccharomyces-cerevisiae-a-fmn-dependent-nad-p-h-quinone-oxidoreductase
#11
Karin Koch, Altijana Hromic, Marija Sorokina, Emilia Strandback, Manuel Reisinger, Karl Gruber, Peter Macheroux
The genome of the yeast Saccharomyces cerevisiae encodes four flavodoxin-like proteins, namely Lot6p, Pst2p, Rfs1p and Ycp4p. Thus far only Lot6p was characterized in detail demonstrating that the enzyme possesses NAD(P)H:quinone oxidoreductase activity. In the present study, we heterologously expressed PST2 in Escherichia coli and purified the produced protein to conduct a detailed biochemical and structural characterization. Determination of the three-dimensional structure by X-ray crystallography revealed that Pst2p adopts the flavodoxin-like fold and forms tetramers independent of cofactor binding...
May 9, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28494583/isolation-identification-and-biological-evaluation-of-phenolic-compounds-from-the-traditional-north-american-confectionery-maple-sugar
#12
Yongqiang Liu, Kenneth Rose, Nicholas Dasilva, Shelby Johnson, Navindra P Seeram
Maple sap, collected from the sugar maple (Acer saccharum) tree, is boiled to produce the popular plant-derived sweetener, maple syrup, which can then be further evaporated to yield the traditional North American confectionery, maple sugar. While maple sap and maple syrup have been previously studied, the phytochemical constituents of maple sugar are unknown. Herein, thirty phenolic compounds, 1-30, primarily lignans, were isolated and identified (by HRESIMS and NMR) from maple sugar. The isolates included the phenylpropanoid-based lignan tetramers, (erythro,erythro)-4'',4'''-dihydroxy-3,3',3'',3''',5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8'';4',8'''-bisoxy-8,8'-dineolignan-7'',7''',9'',9'''-tetraol, 29, and (threo,erythro)-4'',4'''-dihydroxy-3,3',3'',3''',5,5'-hexamethoxy-7,9';7',9-diepoxy-4,8'';4',8'''-bisoxy-8,8'-dineolignan-7'',7''',9'',9'''-tetraol, 30, neither of which have been identified from maple sap or maple syrup before...
May 12, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28488678/a-missense-variant-in-itpr1-provides-evidence-for-autosomal-recessive-sca29-with-asymptomatic-cerebellar-hypoplasia-in-carriers
#13
Joakim Klar, Zafar Ali, Muhammad Farooq, Kamal Khan, Johan Wikström, Maria Iqbal, Shumaila Zulfiqar, Sanam Faryal, Shahid Mahmood Baig, Niklas Dahl
Spinocerebellar ataxias (SCA) comprise a heterogeneous group of inherited neurological disorders characterized by a range of symptoms from both cerebellar and extra cerebellar structures. We investigated the cause of autosomal recessive, congenital SCA in six affected family members from a large consanguineous family. Using whole-exome sequencing, we identified a homozygous ITPR1 missense variant [c.5360T>C; p.(L1787P)] segregating in all affected individuals. Heterozygous carriers were asymptomatic despite cerebellar hypoplasia...
May 10, 2017: European Journal of Human Genetics: EJHG
https://www.readbyqxmd.com/read/28485897/three-dimensional-structures-and-functional-studies-of-two-gh43-arabinofuranosidases-from-weissella-sp-strain-142-and-lactobacillus-brevis
#14
Javier A Linares-Pastén, Peter Falck, Khalil Albasri, Sven Kjellström, Patrick Adlercreutz, Derek T Logan, Eva Nordberg Karlsson
Arabinofuranosidases degrade arabinose-containing oligo and polysaccharides, releasing L-arabinose, which is a potentially useful sugar, shown to reduce glycemic response under certain conditions. Arabinofuranosidases (Arafs) are frequently found in GH43, one of the most common GH-families encoded in genomes in gut microbiota, and hence it is of interest to increase understanding of the function of these enzymes in species occurring in the gut. Here we have produced, characterized and solved the three-dimensional structures, at 1...
May 9, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28484758/calculations-of-current-densities-and-aromatic-pathways-in-cyclic-porphyrin-and-isoporphyrin-arrays
#15
Yannick J Franzke, Dage Sundholm, Florian Weigend
Magnetically induced current density susceptibilities have been studied for a number of cyclic ethyne- and butadiyne-bridged porphyrin and isoporphyrin arrays. The current density susceptibilities have been calculated using the gauge-including magnetically induced current (GIMIC) method, which is interfaced to the TURBOMOLE quantum chemistry code. Aromatic properties and current pathways have been analyzed and discussed by numerical integration of the current density susceptibilities passing selected chemical bonds yielding current strength susceptibilities...
May 9, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28482661/insights-into-formation-and-structure-of-a%C3%AE-oligomers-cross-linked-via-tyrosines
#16
Shuting Zhang, Dillion M Fox, Brigita Urbanc
Alzheimer's disease (AD) pathology is hypothesized to be triggered by amyloid β-protein (Aβ) assembly into oligomers. Oligomer size distributions of both predominant Aβ alloforms, Aβ 40 and Aβ 42 , can be determined in vitro using cross-linking followed by gel electrophoresis. Cross-linking, which can occur in vivo in the presence of copper and hydrogen peroxide, was recently shown to stabilize Aβ oligomers by inhibiting their conversion into fibrils. Whereas several studies showed that cross-linking is facilitated by dityrosine bond formation, the molecular-level mechanism of cross-linking remains unclear...
May 8, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28479252/crystal-structure-of-mdm12-and-combinatorial-reconstitution-of-mdm12-mmm1-ermes-complexes-for-structural-studies
#17
Andrew P AhYoung, Brian Lu, Duilio Cascio, Pascal F Egea
Membrane contact sites between organelles serve as molecular hubs for the exchange of metabolites and signals. In yeast, the Endoplasmic Reticulum - Mitochondrion Encounter Structure (ERMES) tethers these two organelles likely to facilitate the non-vesicular exchange of essential phospholipids. Present in Fungi and Amoebas but not in Metazoans, ERMES is composed of five distinct subunits; among those, Mdm12, Mmm1 and Mdm34 each contain an SMP domain functioning as a lipid transfer module. We previously showed that the SMP domains of Mdm12 and Mmm1 form a hetero-tetramer...
June 17, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/28479043/characterization-of-a-thermostable-glycoside-hydrolase-family-36-%C3%AE-galactosidase-from-caldicellulosiruptor-bescii
#18
Areum Lee, Kyoung-Hwa Choi, Dahye Yoon, Suhkmann Kim, Jaeho Cha
The putative gene cluster involved in the degradation of the raffinose family oligosaccharides (RFO) was identified in Caldicellulosiruptor bescii. Within the cluster, the gene encoding a putative α-galactosidase (CbAga36) was cloned and expressed in Escherichia coli. Size exclusion chromatography of the purified rCbAga36 indicated that the native form was a tetramer. Its primary sequence was similar to the family of glycoside hydrolase 36. The purified recombinant CbAga36 (rCbAga36) was optimally active at pH 5...
May 4, 2017: Journal of Bioscience and Bioengineering
https://www.readbyqxmd.com/read/28471367/crystal-structure-of-the-novel-amino-acid-racemase-isoleucine-2-epimerase-from-lactobacillus-buchneri
#19
Junji Hayashi, Yuta Mutaguchi, Yume Minemura, Noriko Nakagawa, Kazunari Yoneda, Taketo Ohmori, Toshihisa Ohshima, Haruhiko Sakuraba
Crystal structures of Lactobacillus buchneri isoleucine 2-epimerase, a novel branched-chain amino-acid racemase, were determined for the enzyme in the apo form, in complex with pyridoxal 5'-phosphate (PLP), in complex with N-(5'-phosphopyridoxyl)-L-isoleucine (PLP-L-Ile) and in complex with N-(5'-phosphopyridoxyl)-D-allo-isoleucine (PLP-D-allo-Ile) at resolutions of 2.77, 1.94, 2.65 and 2.12 Å, respectively. The enzyme assembled as a tetramer, with each subunit being composed of N-terminal, C-terminal and large PLP-binding domains...
May 1, 2017: Acta Crystallographica. Section D, Structural Biology
https://www.readbyqxmd.com/read/28471195/-application-of-pla-method-for-detection-of-p53-p63-p73-complexes-in-situ-in-tumour-cells-and-tumour-tissue
#20
V Hrabal, M Nekulová, R Nenutil, J Holčaková, P J Coates, B Vojtěšek
BACKGROUND: PLA (proximity ligation assay) can be used for detection of protein-protein interactions in situ directly in cells and tissues. Due to its high sensitivity and specificity it is useful for detection, localization and quantification of protein complexes with single molecule resolution. One of the mechanisms of mutated p53 gain of function is formation of proten-protein complexes with other members of p53 family - p63 and p73. These interactions influences chemosensitivity and invasivity of cancer cells and this is why these complexes are potential targets of anti-cancer therapy...
2017: Klinická Onkologie: Casopis Ceské a Slovenské Onkologické Spolecnosti
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