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https://www.readbyqxmd.com/read/28340512/activation-mechanisms-of-%C3%AE-v%C3%AE-3-integrin-by-binding-to-fibronectin-a-computational-study
#1
Lingyun Wang, Di Pan, Qi Yan, Yuhua Song
Integrin αVβ3 plays an important role in regulating cellular activities and in human diseases. Although the structure of αVβ3 has been studied by crystallography and electron microscopy, the detailed activation mechanism of integrin αVβ3 induced by fibronectin (Fn) remains unclear. In this study, we investigated the conformational and dynamical motion changes of Mn(2+) -bound integrin αVβ3 by binding to Fn with molecular dynamics simulations. Results showed that Fn binding to integrin αVβ3 caused the changes of the conformational flexibility of αVβ3 domains, the essential mode of motion for the domains of αV subunit and β3 subunit and the degrees of correlated motion of residues between the domains of αV subunit and β3 subunit of integrin αVβ3...
March 24, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28340507/understanding-the-contribution-of-disulphide-bridges-to-the-folding-and-misfolding-of-an-anti-a%C3%AE-scfv
#2
Laia Montoliu-Gaya, Jose C Martínez, Sandra Villegas
ScFv-h3D6 is a single chain variable fragment that precludes Aβ peptide-induced cytotoxicity by withdrawing Aβ oligomers from the amyloid pathway to the worm-like pathway. Production of scFv molecules is not a straightforward procedure because of the occurrence of disulphide scrambled conformations generated in the refolding process. Here, we separately removed the disulphide bond of each domain and solved the scrambling problem; and then, we intended to compensate the loss of thermodynamic stability by adding three C-terminal elongation mutations previously described to stabilize the native fold of scFv-h3D6...
March 24, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28340422/the-clinicopathologic-relevance-of-reck-gene-polymorphisms-in-ameloblastoma
#3
Xudong Zhang, Jie Wang, Huijuan Liu, Yanning Zhang, Fusheng Dong
OBJECTIVE: To investigate the relationship between RECK gene polymorphisms and the clinicopathologic features of ameloblastoma. DESIGN: Normal gingival mucosa specimens were obtained from 10 healthy volunteers. Ameloblastomas were surgically removed from 30 patients and part of the tumor specimens were used to detect RECK gene polymorphisms by using PCR-single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing analysis. Expression of RECK and MMP-9 protein was measured using western blot...
March 16, 2017: Archives of Oral Biology
https://www.readbyqxmd.com/read/28340381/studying-the-adsorption-of-dna-nanostructures-on-graphene-in-the-aqueous-phase-using-molecular-dynamic-simulations
#4
Jixue Sun, Yang Li, Jianping Lin
DNA nanostructures can undergo large structural fluctuations and deviate from their intended configurations. In this work, two model DNA nanostructures (i.e., Nan and Kai) were designed based on the shape of the two Chinese characters of the name of Nankai University, and additional single-stranded DNA fragments were added to interact with graphene. During four 50-ns molecular dynamic simulations in aqueous solution, the DNA nanostructures adsorbed onto graphene demonstrated more stable conformations with lower root mean square deviations and smaller coordinate changes in the z-axis direction than the DNA nanostructures that were not adsorbed onto graphene...
March 9, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28340354/mechanism-of-substrate-translocation-in-an-alternating-access-transporter
#5
Naomi R Latorraca, Nathan M Fastman, A J Venkatakrishnan, Wolf B Frommer, Ron O Dror, Liang Feng
Transporters shuttle molecules across cell membranes by alternating among distinct conformational states. Fundamental questions remain about how transporters transition between states and how such structural rearrangements regulate substrate translocation. Here, we capture the translocation process by crystallography and unguided molecular dynamics simulations, providing an atomic-level description of alternating access transport. Simulations of a SWEET-family transporter initiated from an outward-open, glucose-bound structure reported here spontaneously adopt occluded and inward-open conformations...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340337/structural-basis-of-rna-polymerase-i-transcription-initiation
#6
Christoph Engel, Tobias Gubbey, Simon Neyer, Sarah Sainsbury, Christiane Oberthuer, Carlo Baejen, Carrie Bernecky, Patrick Cramer
Transcription initiation at the ribosomal RNA promoter requires RNA polymerase (Pol) I and the initiation factors Rrn3 and core factor (CF). Here, we combine X-ray crystallography and cryo-electron microscopy (cryo-EM) to obtain a molecular model for basal Pol I initiation. The three-subunit CF binds upstream promoter DNA, docks to the Pol I-Rrn3 complex, and loads DNA into the expanded active center cleft of the polymerase. DNA unwinding between the Pol I protrusion and clamp domains enables cleft contraction, resulting in an active Pol I conformation and RNA synthesis...
March 23, 2017: Cell
https://www.readbyqxmd.com/read/28340300/synthesis-of-3-o-sulfated-oligosaccharides-to-understand-the-relationship-between-structures-and-functions-of-heparan-sulfate
#7
Zhangjie Wang, Po-Hung Hsieh, Yongmei Xu, David Thieker, Evangeline Juan En Chai, Shaoshuai Xie, Brian Cooley, Robert Woods, Lianli Chi, Jian Liu
The sulfation at the 3-OH position of glucosamine is an important modification in forming structural domains for heparan sulfate to enable its biological functions. Seven 3-O-sulfotransferase isoforms in the human genome are involved in the biosynthesis of 3-O-sulfated heparan sulfate. As a rare modification present in heparan sulfate, the availability of 3-O-sulfated oligosaccharides is very limited. Here, we report the use of a chemoenzymatic synthetic approach to synthesize six 3-O-sulfated oligosaccharides, including three hexasaccharides and three octasaccharides...
March 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28340189/the-relationship-between-pain-severity-and-alcohol-use-among-school-aged-children-and-adolescents-the-moderating-role-of-drinking-motives
#8
Claudia Horn-Hofmann, Zina Trost, Anne Hublet, Sylvie Mrug, Joris Van Damme, Tine Vervoort
Objective. : Evidence from adult samples suggests a co-occurrence between pain and alcohol abuse. However, studies in adolescents are scarce and results are inconsistent, with some studies observing heightened and others observing reduced alcohol consumption in adolescents suffering from pain. We hypothesized that in adolescents the association between pain and alcohol use will be moderated by drinking motives. Methods. : Data from a large representative sample of Flemish school children and adolescents (N = 10,650, 50...
March 15, 2017: Pain Medicine: the Official Journal of the American Academy of Pain Medicine
https://www.readbyqxmd.com/read/28339844/intensity-modulated-radiotherapy-using-two-static-ports-of-tomotherapy-for-breast-cancer-after-conservative-surgery-dosimetric-comparison-with-other-treatment-methods-and-3-year-clinical-results
#9
Aiko Nagai, Yuta Shibamoto, Masanori Yoshida, Koji Inoda, Yuzo Kikuchi
This study investigated the differences in dose-volume parameters for the breast and normal tissues during TomoDirectTM (TD) intensity-modulated radiation therapy (IMRT), TD-3D conformal radiotherapy (3DCRT) and 3DCRT plans, all using two beams, and analyzed treatment outcomes of two-beam TD-IMRT for breast cancer after breast-conserving surgery. Between August 2011 and January 2015, 152 patients were treated using two-beam TD-IMRT with 50 Gy/25 fractions. Among them, 20 patients with left-sided breast cancer were randomly chosen, and two-beam TD-IMRT, TD-3DCRT and 3DCRT plans were created for each patient...
February 23, 2017: Journal of Radiation Research
https://www.readbyqxmd.com/read/28335571/3-substituted-n-benzylpyrazine-2-carboxamide-derivatives-synthesis-antimycobacterial-and-antibacterial-evaluation
#10
Lucia Semelková, Ondřej Janďourek, Klára Konečná, Pavla Paterová, Lucie Navrátilová, František Trejtnar, Vladimír Kubíček, Jiří Kuneš, Martin Doležal, Jan Zitko
A series of substituted N-benzyl-3-chloropyrazine-2-carboxamides were prepared as positional isomers of 5-chloro and 6-chloro derivatives, prepared previously. During the aminolysis of the acyl chloride, the simultaneous substitution of chlorine with benzylamino moiety gave rise to N-benzyl-3-(benzylamino)pyrazine-2-carboxamides as side products, in some cases. Although not initially planned, the reaction conditions were modified to populate this double substituted series. The final compounds were tested against four mycobacterial strains...
March 21, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28335521/gene-transformation-induced-changes-in-chemical-functional-group-features-and-molecular-structure-conformation-in-alfalfa-plants-co-expressing-lc-bhlh-and-c1-myb-transcriptive-flavanoid-regulatory-genes-effects-of-single-gene-and-two-gene-insertion
#11
Ravindra G Heendeniya, Peiqiang Yu
Alfalfa (Medicago sativa L.) genotypes transformed with Lc-bHLH and Lc transcription genes were developed with the intention of stimulating proanthocyanidin synthesis in the aerial parts of the plant. To our knowledge, there are no studies on the effect of single-gene and two-gene transformation on chemical functional groups and molecular structure changes in these plants. The objective of this study was to use advanced molecular spectroscopy with multivariate chemometrics to determine chemical functional group intensity and molecular structure changes in alfalfa plants when co-expressing Lc-bHLH and C1-MYB transcriptive flavanoid regulatory genes in comparison with non-transgenic (NT) and AC Grazeland (ACGL) genotypes...
March 20, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/28335389/characteristics%C3%A2-and%C3%A2-lethality%C3%A2-of%C3%A2-a%C3%A2-novel%C3%A2-recombinant%C3%A2-dermonecrotic%C3%A2-venom%C3%A2-phospholipase%C3%A2-d%C3%A2-from%C3%A2-hemiscorpius%C3%A2-lepturus
#12
Elham Torabi, Mahdi Behdani, Mohammad Hosseininejad Chafi, Reza Moazzami, Jean-Marc Sabatier, Vahid Khalaj, Delavar Shahbazzadeh, Kamran Pooshang Bagheri
Hemoscorpius lepturus is the most medically important scorpion in Iran. The clinical signs of H. lepturus envenomation are remarkably similar to those reported for brown spiders, including dermonecrosis, hematuria, renal failure and even death. The lethality and toxicity of brown spiders' venom have been attributed to its phospholipase D activity. This study aims to identify a phospholipase D with possible lethality and dermonecrotic activity in H. lepturus venom. In this study, a cDNA library of the venom glands was generated by Illumina RNA sequencing...
March 13, 2017: Toxins
https://www.readbyqxmd.com/read/28335361/preparation-and-characterization-of-zirconia-coated-nanodiamonds-as-a-pt-catalyst-support-for-methanol-electro-oxidation
#13
Jing Lu, Jianbing Zang, Yanhui Wang, Yongchao Xu, Xipeng Xu
Zirconia-coated nanodiamond (ZrO₂/ND) electrode material was successfully prepared by one-step isothermal hydrolyzing from ND-dispersed ZrOCl₂·8H₂O aqueous solution. High-resolution transmission electron microscopy reveals that a highly conformal and uniform ZrO₂ shell was deposited on NDs by this simple method. The coating obtained at 90 °C without further calcination was mainly composed of monoclinic nanocrystalline ZrO₂ rather than common amorphous Zr(OH)₄ clusters. The ZrO₂/NDs and pristine ND powder were decorated with platinum (Pt) nanoparticles by electrodeposition from 5 mM chloroplatinic acid solution...
December 2, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335296/controlled-mechanical-cracking-of-metal-films-deposited-on-polydimethylsiloxane-pdms
#14
Andreas Polywka, Luca Stegers, Oliver Krauledat, Thomas Riedl, Timo Jakob, Patrick Görrn
Stretchable large area electronics conform to arbitrarily-shaped 3D surfaces and enables comfortable contact to the human skin and other biological tissue. There are approaches allowing for large area thin films to be stretched by tens of percent without cracking. The approach presented here does not prevent cracking, rather it aims to precisely control the crack positions and their orientation. For this purpose, the polydimethylsiloxane (PDMS) is hardened by exposure to ultraviolet radiation (172 nm) through an exposure mask...
September 9, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335290/the-effect-of-viscous-air-damping-on-an-optically-actuated-multilayer-mos%C3%A2-nanomechanical-resonator-using-fabry-perot-interference
#15
Yumei She, Cheng Li, Tian Lan, Xiaobin Peng, Qianwen Liu, Shangchun Fan
We demonstrated a multilayer molybdenum disulfide (MoS₂) nanomechanical resonator by using optical Fabry-Perot (F-P) interferometric excitation and detection. The thin circular MoS₂ nanomembrane with an approximate 8-nm thickness was transferred onto the endface of a ferrule with an inner diameter of 125 μm, which created a low finesse F-P interferometer with a cavity length of 39.92 μm. The effects of temperature and viscous air damping on resonance behavior of the resonator were investigated in the range of -10-80 °C...
September 5, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335237/dna-sequencing-by-hexagonal-boron-nitride-nanopore-a-computational-study
#16
Liuyang Zhang, Xianqiao Wang
The single molecule detection associated with DNA sequencing has motivated intensive efforts to identify single DNA bases. However, little research has been reported utilizing single-layer hexagonal boron nitride (hBN) for DNA sequencing. Here we employ molecular dynamics simulations to explore pathways for single-strand DNA (ssDNA) sequencing by nanopore on the hBN sheet. We first investigate the adhesive strength between nucleobases and the hBN sheet, which provides the foundation for the hBN-base interaction and nanopore sequencing mechanism...
June 6, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335224/structural-changes-induced-in-grapevine-vitis-vinifera-l-dna-by-femtosecond-ir-laser-pulses-a-surface-enhanced-raman-spectroscopic-study
#17
Nicoleta E Dina, Cristina M Muntean, Nicolae Leopold, Alexandra Fălămaș, Adela Halmagyi, Ana Coste
In this work, surface-enhanced Raman spectra of ten genomic DNAs extracted from leaf tissues of different grapevine (Vitis vinifera L.) varieties, respectively, are analyzed in the wavenumber range 300-1800 cm(-1). Furthermore, structural changes induced in grapevine genomic nucleic acids upon femtosecond (170 fs) infrared (IR) laser pulse irradiation (λ = 1100 nm) are discussed in detail for seven genomic DNAs, respectively. Surface-enhanced Raman spectroscopy (SERS) signatures, vibrational band assignments and structural characterization of genomic DNAs are reported for each case...
May 25, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334906/conformational-polymorphism-or-structural-invariance-in-dna-photoinduced-lesions-implications-for-repair-rates
#18
François Dehez, Hugo Gattuso, Emmanuelle Bignon, Christophe Morell, Elise Dumont, Antonio Monari
DNA photolesions constitute a particularly deleterious class of molecular defects responsible for the insurgence of a vast majority of skin malignant tumors. Dimerization of two adjacent thymines or cytosines mostly gives rise to cyclobutane pyrimidine dimers (CPD) and pyrimidine(6-4)pyrimidone 64-PP as the most common defects. We perform all-atom classical simulations, up to 2 μs, of CPD and 64-PP embedded in a 16-bp duplex, which reveal the constrasted behavior of the two lesions. In particular we evidence a very limited structural deformation induced by CPD while 64-PP is characterized by a complex structural polymorphism...
February 28, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28334865/structure-of-human-pofut1-its-requirement-in-ligand-independent-oncogenic-notch-signaling-and-functional-effects-of-dowling-degos-mutations
#19
Brian J McMillan, Brandon Zimmerman, Emily D Egan, Michael Lofgren, Xiang Xu, Anthony Hesser, Stephen C Blacklow
Protein O-fucosyltransferase-1 (POFUT1), which transfers fucose residues to acceptor sites on serine and threonine residues of epidermal growth factor-like repeats of recipient proteins, is essential for Notch signal transduction in mammals. Here, we examine the consequences of POFUT1 loss on the oncogenic signaling associated with certain leukemia-associated mutations of human Notch1, report the structures of human POFUT1 in free and GDP-fucose bound states, and assess the effects of Dowling-Degos mutations on human POFUT1 function...
March 17, 2017: Glycobiology
https://www.readbyqxmd.com/read/28334864/coordination-among-tertiary-base-pairs-results-in-an-efficient-frameshift-stimulating-rna-pseudoknot
#20
Yu-Ting Chen, Kai-Chun Chang, Hao-Teng Hu, Yi-Lan Chen, You-Hsin Lin, Chiung-Fang Hsu, Cheng-Fu Chang, Kung-Yao Chang, Jin-Der Wen
Frameshifting is an essential process that regulates protein synthesis in many viruses. The ribosome may slip backward when encountering a frameshift motif on the messenger RNA, which usually contains a pseudoknot structure involving tertiary base pair interactions. Due to the lack of detailed molecular explanations, previous studies investigating which features of the pseudoknot are important to stimulate frameshifting have presented diverse conclusions. Here we constructed a bimolecular pseudoknot to dissect the interior tertiary base pairs and used single-molecule approaches to assess the structure targeted by ribosomes...
February 21, 2017: Nucleic Acids Research
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