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https://www.readbyqxmd.com/read/28922858/contributions-of-the-medial-prefrontal-cortex-to-social-influence-in-economic-decision-making
#1
M A J Apps, N Ramnani
Economic decisions are guided by highly subjective reward valuations (SVs). Often these SVs are over-ridden when individuals conform to social norms. Yet, the neural mechanisms that underpin the distinct processing of such normative reward valuations (NVs) are poorly understood. The dorsomedial and ventromedial portions of the prefrontal cortex (dmPFC/vmPFC) are putatively key regions for processing social and economic information respectively. However, the contribution of these regions to economic decisions guided by social norms is unclear...
September 1, 2017: Cerebral Cortex
https://www.readbyqxmd.com/read/28922740/a-conserved-dggk-motif-is-essential-for-the-function-of-the-pglb-oligosaccharyltransferase-from-campylobacter-jejuni
#2
Yasmin Barre, Harald Nothaft, Cody Thomas, Xin Liu, Jianjun Li, Kenneth K S Ng, Christine M Szymanski
In Campylobacter jejuni, the PglB oligosaccharyltransferase catalyzes the transfer of a heptasaccharide from a lipid donor to asparagine within the D/E-X1-N-X2-S/T sequon (X1,2 ≠ P) or releases this heptasaccharide as free oligosaccharides (fOS). Using available crystal structures and sequence alignments, we identified a DGGK motif near the active site of PglB that is conserved among all Campylobacter species. We demonstrate that amino acid substitutions in the aspartate and lysine residues result in loss of protein glycosylation in the heterologous Escherichia coli system...
October 1, 2017: Glycobiology
https://www.readbyqxmd.com/read/28922636/effects-of-mutations-on-active-site-conformation-and-dynamics-of-rna-dependent-rna-polymerase-from-coxsackievirus-b3
#3
Hujun Shen, Mingsen Deng, Yachao Zhang
Recent crystal structures of RNA-dependent RNA polymerase (3D(pol)) from Coxsackievirus B3 (CVB3) revealed that a tyrosine mutation at Phe364 (F364Y) resulted in structures with open active site whereas a hydrophobic mutation at Phe364 (F364A) led to conformations with closed active site. Besides, the crystal structures showed that the F364W mutation had no preference between the open and closed active sites, similar to wild-type. In this paper, we present a molecular dynamics (MD) study on CVB3 3D(pol) in order to address some important questions raised by experiments...
September 12, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28922633/protein-extraction-into-the-bicontinuous-microemulsion-phase-of-a-water-sds-pentanol-dodecane-winsor-iii-system-effect-on-nanostructure-and-protein-conformation
#4
Douglas G Hayes, Ran Ye, Rachel N Dunlap, Matthew J Cuneo, Sai Venkatesh Pingali, Hugh M O'Neill, Volker S Urban
Bicontinuous microemulsions (BμEs), consisting of water and oil nanodomains separated by surfactant monolayers of near-zero curvature, are potentially valuable systems for purification and delivery of biomolecules, for hosting multiphasic biochemical reactions, and as templating media for preparing nanomaterials. We formed Winsor-III systems by mixing aqueous protein and sodium dodecyl sulfate (SDS) solutions with dodecane and 1-pentanol (cosurfactant) to efficiently extract proteins into the middle (BμE) phase...
September 7, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28922605/alkane-coiling-in-perfluoroalkane-solutions-a-new-primitive-solvophobic-effect
#5
Pedro Morgado, Ana Rosa Garcia, Luís F G Martins, Laura M Ilharco, Eduardo J M Filipe
In this work we demonstrate that n-alkanes coil when mixed with perfluoroalkanes, changing their conformational equilibria to more globular states, with a higher number of gauche conformations. The new coiling effect is here observed in fluids governed exclusively by dispersion interactions, contrarily to other examples in which hydrogen bonding and polarity play important roles. FTIR spectra of liquid mixtures of n-hexane and perfluorohexane unambiguously reveal that the population of n-hexane molecules in all-trans conformation reduces from 32% in the pure n-alkane to practically zero...
September 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28922599/effect-of-t%C3%A2-t-mismatch-on-dna-dynamics-probed-by-minor-groove-binders-comparison-of-dynamic-stokes-shifts-of-hoechst-and-dapi
#6
Him Shweta, Moirangthem Kiran Singh, Kavita Yadav, Sachin Dev Verma, Nibedita Pal, Sobhan Sen
Recognition of DNA base mismatches and their subsequent repair by enzymes is vital for genomic stability. However, it is difficult to comprehend such process in which enzymes sense and repair different types of mismatches with different ability. It has been suggested that the differential structural changes of mismatched-bases act as cues to the repair enzymes, although effect of such DNA structural changes on surrounding water and ion dynamics is inevitable due to strong electrostatic coupling among them. Thus, collective dynamics of DNA, water and ions near the mismatch site is believed to be important for mismatch recognition and repair mechanism...
September 18, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28922509/molecular-switching-in-confined-spaces-effects-of-encapsulating-the-dha-vhf-photo-switch-in-cucurbiturils
#7
Michael Å Petersen, Brian Rasmussen, Nicolaj N Andersen, Stephan P A Sauer, Mogens Brøndsted Nielsen, Sophie R Beeren, Michael Pittelkow
Confinement of reactive chemical species uniquely affects chemical reactivity by restricting the physical space available and by restricting access to interactions with the solvent. In Nature, for example, confined protein binding pockets govern processes following photoisomerization reactions and the isomerizations themselves. Here we describe the first example of a dihydroazulene/vinylheptafulvene (DHA/VHF) photo-switch functioning in water, and we show how its switching behavior is strongly influenced by supramolecular interactions with a series of cucurbit[n]uril (CB) host molecules...
September 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28922503/modulating-the-structural-properties-of-alpha-gamma-hybrid-peptides-by-alpha-amino-acid-residues-uniform-12-helix-versus-mixed-12-10-helix
#8
Rajkumar Misra, K Muruga Poopathi Raja, Hans-Jörg Hofmann, Hosahudya Gopi
The most important natural a- and 310-helices are stabilized by unidirectional intramolecular hydrogen bonds along the helical cylinder. In contrast, we are reporting here on 12/10-helical conformations with alternately changing H-bond directionality in sequences of alpha,gamma-hybrid peptides [P1: Boc-Ala-Aic-Ala-Aic-COOH; P2: Boc-Leu-Aic-Leu-Aic-OEt; P3: Boc-Leu-Aic-Leu-Aic-Leu-Aic-Aib-OMe; P4: Boc-Ala-Aic-Ala-Aic-Ala-Aic-Ala-OMe; P5: Boc-Leu-Aic-Leu-Aic-Leu-Aic-Leu-Aic-Aib-OMe] composed of natural a-amino acids and the achiral gamma4,4-dimethyl substituted g-amino acid Aic in solution and in single crystals...
September 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28922460/a-raman-spectroscopic-investigation-of-the-mechanism-of-the-reduction-of-hair-with-thioglycerol-and-the-accompanying-disulfide-conformational-changes
#9
A Kuzuhara
OBJECTIVE: The objective of our research was to investigate the reduction mechanism of thioglycerol (TG) on hair keratin fibres. METHODS: The structure of cross-sections at various depths of virgin white human hair resulting from the permanent waving process with TG was directly analyzed at the molecular level using Raman spectroscopy. Also, the penetration of TG for the cross-sectional samples dyed with methylene blue was observed by optical microscopy. RESULTS: The gauche-gauche-gauche (GGG) and gauche-gauche-trans (GGT) conformations of disulfide (-SS-) groups remarkably decreased, while the trans-gauche-trans (TGT) conformation increased by performing the reduction process with TG...
September 18, 2017: International Journal of Cosmetic Science
https://www.readbyqxmd.com/read/28922450/structural-insight-into-the-xtacc3-xmap215-interaction-from-cd-and-nmr-studies-on-model-peptides
#10
Angélica Partida-Hanon, Miguel A Treviño, Miguel Mompeán, Ma Ángeles Jiménez, Marta Bruix
TACC3 is a centrosomal adaptor protein that plays important roles during mitotic spindle assembly. It interacts with chTOG/XMAP215, which catalyzes the addition of tubulin dimers during microtubule growth. A 3D coiled-coil model for this interaction is available but the structural details are not well described. To characterize this interaction at atomic resolution, we have designed a simplified version of the system based on small peptides. Four different peptides have been studied by circular dichroism and nuclear magnetic resonance both singly and in all possible combinations; namely, five peptide pairs and two trios...
September 18, 2017: Biopolymers
https://www.readbyqxmd.com/read/28922400/protein-folding-misfolding-and-aggregation-the-importance-of-two-electron-stabilizing-interactions
#11
Andrzej Stanisław Cieplak
Proteins associated with neurodegenerative diseases are highly pleiomorphic and may adopt an all-α-helical fold in one environment, assemble into all-β-sheet or collapse into a coil in another, and rapidly polymerize in yet another one via divergent aggregation pathways that yield broad diversity of aggregates' morphology. A thorough understanding of this behaviour may be necessary to develop a treatment for Alzheimer's and related disorders. Unfortunately, our present comprehension of folding and misfolding is limited for want of a physicochemical theory of protein secondary and tertiary structure...
2017: PloS One
https://www.readbyqxmd.com/read/28922398/role-of-the-p2-residue-of-human-alpha-1-antitrypsin-in-determining-target-protease-specificity
#12
Hye-Shin Chung, Ji-Sun Kim, Sang Mee Lee, Soon Jae Park
Alpha 1-antitrypsin (A1AT) is a serine protease inhibitor that mainly inhibits neutrophil elastase in the lungs. A variant of A1AT at the P1 position with methionine 358 to arginine (A1AT-Pittsburgh) is a rapid inhibitor of thrombin with greatly diminished anti-elastase activity. The P2 residue (position 357) of A1AT-Pittsburgh has been shown to play an important role in interactions with thrombin and kallikrein, but the role of P2 residue in wild-type A1AT has largely been unraveled. Here, we investigated the effects of P2 proline substitutions in wild-type A1AT on interactions with porcine pancreatic elastase (PPE) and human neutrophil elastase (HNE)...
2017: PloS One
https://www.readbyqxmd.com/read/28922369/crimean-congo-hemorrhagic-fever-virus-nucleocapsid-protein-has-dual-rna-binding-modes
#13
Subbiah Jeeva, Sean Pador, Brittany Voss, Safder Saieed Ganaie, Mohammad Ayoub Mir
Crimean Congo hemorrhagic fever, a zoonotic viral disease, has high mortality rate in humans. There is currently no vaccine for Crimean Congo hemorrhagic fever virus (CCHFV) and chemical interventions are limited. The three negative sense genomic RNA segments of CCHFV are specifically encapsidated by the nucleocapsid protein into three ribonucleocapsids, which serve as templates for the viral RNA dependent RNA polymerase. Here we demonstrate that CCHFV nucleocapsid protein has two distinct binding modes for double and single strand RNA...
2017: PloS One
https://www.readbyqxmd.com/read/28922112/effects-of-flexible-dry-electrode-design-on-electrodermal-activity-stimulus-response-detection
#14
Peter A Haddad, Amir Servati, Saeid Soltanian, Frank Ko, Peyman Servati
OBJECTIVE: The focus of this research is to evaluate the effects of design parameters including surface area, distance between and geometry of dry flexible electrodes on electrodermal activity (EDA) stimulus response detection. METHODS: EDA is a result of the autonomic nervous system (ANS) being stimulated, which causes sweat and changes the electrical characteristics of the skin. Standard silver/silver chloride (Ag/AgCl) EDA electrodes are rigid and lack conformability in contact with skin...
September 18, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28921993/lactam-stapled-cell-penetrating-peptides-cell-uptake-and-membrane-binding-properties
#15
Marco J Klein, Samuel Schmidt, Parvesh Wadhwani, Jochen Bürck, Johannes Reichert, Sergii Afonin, Marina Berditsch, Tim Schober, Roland Brock, Manfred Kansy, Anne S Ulrich
Stapling of side chains to stabilize an α-helical structure has been generally associated with an increased uptake of CPPs. Here, we compare 4 amphiphilic stapled peptides with their linear counterparts in terms of their membrane binding and conformational features, in order to correlate these with uptake efficiency and toxicological effects. The impact of lactam stapling was found to vary strongly with regard to the different aspects of peptide-membrane interactions. Nearly all stapled peptides caused less membrane perturbation (vesicle leakage, hemolysis, bacterial lysis) than their linear counterparts...
September 18, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28921984/melting-behavior-of-a-dna-four-way-junction-using-spectroscopic-and-calorimetric-techniques
#16
Carolyn E Carr, Luis A Marky
Intramolecular four-way junctions are structures present during homologous recombination, repair of double stranded DNA breaks and integron recombination, in addition to many others. Because of the wide range of biological processes four-way junctions are involved in, understanding how and under what conditions these structures form is critical. In this work, we used a combination of spectroscopic and calorimetric techniques to present a complete thermodynamic description of the unfolding of a DNA four-way junction (FWJ) and its appropriate control stem-loop motifs (Dumbbell, GAAATT-Hp, CTATC-Hp, GTGC-Hp, and GCGC-Hp)...
September 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28921967/quantifying-secondary-structure-changes-in-calmodulin-using-2d-ir-spectroscopy
#17
Lucy Minnes, Daniel John Shaw, Benjamin P Cossins, Paul M Donaldson, Gregory M Greetham, Michael Towrie, Anthony Parker, Matthew James Baker, Alistair J Henry, Richard J Taylor, Neil T Hunt
Revealing the details of biomolecular processes in solution needs tools that can monitor structural dynamics over a range of time and length scales. We assess the ability of 2D-IR spectroscopy in combination with multivariate data analysis to quantify changes in secondary structure of the multifunctional calcium-binding messenger protein Calmodulin (CaM) as a function of temperature and Ca2+ concentration. Our approach produced quantitative agreement with circular dichroism (CD) spectroscopy in detecting the domain melting transitions of Ca2+-free (apo) CaM (reduction in α-helix structure by 13% (CD) and 15% (2D))...
September 18, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28921964/versatile-synthetic-route-for-%C3%AE-functionalized-chlorins-and-porphyrins-by-varying-the-size-of-michael-donors-syntheses-photophysical-and-electrochemical-redox-properties
#18
Nivedita Chaudhri, Nitika Grover, Muniappan Sankar
One-pot facile synthesis and characterization of novel β-substituted meso-tetraphenylporphyrins and/or chlorins were described. The high regioselective reactivity of active methylene compounds in Michael addition reaction was reported to access β-substituted trans-chlorins. Size-dependent approach was applied for the fine-tuning of product formation from porphyrins to chlorins. Notably, we were able to isolate mono/trisubstituted porphyrin and/or di/tetra-substituted chlorin from one-pot synthesis for the first time in porphyrin chemistry...
September 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28921899/stimulus-induced-conformational-transformation-of-cyclic-peptide-for-selective-cell-targeting-on-off-gatekeeper-of-mesoporous-nanocarrier
#19
Jeonghun Lee, Eun-Taex Oh, Jaehun Song, Ha Gyeong Kim, Heon Joo Park, Chulhee Kim
The αvβ3 integrin is upregulated on many cancer cells. We designed a dual functional cyclic peptide gatekeeper with a capability of stimuli-responsive conformational transformation which could serve as a selective cell targeting on-off gatekeeper for mesoporous nanocarriers. The advantage of employing the motif of stimuli-induced conformational transformation of cyclic peptides is that they could be utilized not only as an on-off gatekeeper for the triggered release of cargo drugs but also as a targeting ligand of the carriers to desired cells with their respective binding receptors...
September 17, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28921848/interconversion-rates-between-conformational-states-as-rationale-for-the-membrane-permeability-of-cyclosporines
#20
Jagna Witek, Max Mühlbauer, Bettina G Keller, Markus Blatter, Axel Meissner, Trixie Wagner, Sereina Riniker
Cyclic peptides have regained interest as potential inhibitors of challenging targets, but have often a low bioavailability. The natural product cyclosporine A (CsA) is the textbook exception. Despite its size and polar backbone it is able to passively cross membranes. This ability is hypothesized to be due to a conformational change from the low-energy conformation in water to a "congruent" conformation that is populated both in water and inside the membrane. Here, we use a combination of NMR measurements and kinetic models based on molecular dynamics simulations to rationalize the difference in the membrane permeability of cyclosporine E (CsE) and CsA...
September 17, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
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