1,721,089 research outputs found
sj-docx-1-pom-10.1177_03057356241238004 – Supplemental material for Charity begins with prosocial music: Musical differences in intertemporal prosocial discounting and generosity
No full textSupplemental material, sj-docx-1-pom-10.1177_03057356241238004 for Charity begins with prosocial music: Musical differences in intertemporal prosocial discounting and generosity by Mei Hong, Dapeng Liang and Teng Lu in Psychology of Music</p
Investigation of the Curvature Induction and Membrane Localization of the Influenza Virus M2 Protein Using Static and Off-Magic-Angle Spinning Solid-State Nuclear Magnetic Resonance of Oriented Bicelles
Full text linkA wide variety of membrane proteins induce membrane curvature for function; thus, it is important to develop new methods to simultaneously determine membrane curvature and protein binding sites in membranes with multiple curvatures. We introduce solid-state nuclear magnetic resonance (NMR) methods based on magnetically oriented bicelles and off-magic-angle spinning (OMAS) to measure membrane curvature and the binding site of proteins in mixed-curvature membranes. We demonstrate these methods on the influenza virus M2 protein, which not only acts as a proton channel but also mediates virus assembly and membrane scission. An M2 peptide encompassing the transmembrane (TM) domain and an amphipathic helix, M2(21–61), was studied and compared with the TM peptide (M2TM). Static [superscript 31]P NMR spectra of magnetically oriented 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) bicelles exhibit a temperature-independent isotropic chemical shift in the presence of M2(21–61) but not M2TM, indicating that the amphipathic helix confers the ability to generate a high-curvature phase. Two-dimensional (2D) [superscript 31]P spectra indicate that this high-curvature phase is associated with the DHPC bicelle edges, suggestive of the structure of budding viruses from the host cell. [superscript 31]P- and [superscript 13]C-detected [superscript 1]H relaxation times of the lipids indicate that the majority of M2(21–61) is bound to the high-curvature phase. Using OMAS experiments, we resolved the [superscript 31]P signals of lipids with identical headgroups based on their distinct chemical shift anisotropies. On the basis of this resolution, 2D [superscript 1]H–[superscript 31]P correlation spectra show that the amide protons in M2(21–61) correlate with the DMPC but not DHPC [superscript 31]P signal of the bicelle, indicating that a small percentage of M2(21–61) partitions into the planar region of the bicelles. These results show that the amphipathic helix induces high membrane curvature and localizes the protein to this phase, in good agreement with the membrane scission function of the protein. These bicelle-based relaxation and OMAS solid-state NMR techniques are generally applicable to curvature-inducing membrane proteins such as those involved in membrane trafficking, membrane fusion, and cell division.National Institutes of Health (U.S.) (NIH Grant GM088204
Solid-State Nuclear Magnetic Resonance Investigation of the Structural Topology and Lipid Interactions of a Viral Fusion Protein Chimera Containing the Fusion Peptide and Transmembrane Domain
No full textThe fusion peptide
(FP) and transmembrane domain (TMD) of viral
fusion proteins play important roles during virus–cell membrane
fusion, by inducing membrane curvature and transient dehydration.
The structure of the water-soluble ectodomain of viral fusion proteins
has been extensively studied crystallographically, but the structures
of the FP and TMD bound to phospholipid membranes are not well understood.
We recently investigated the conformations and lipid interactions
of the separate FP and TMD peptides of parainfluenza virus 5 (PIV5)
fusion protein F using solid-state nuclear magnetic resonance. These
studies provide structural information about the two domains when
they are spatially well separated in the fusion process. To investigate
how these two domains are structured relative to each other in the
postfusion state, when the ectodomain forms a six-helix bundle that
is thought to force the FP and TMD together in the membrane, we have
now expressed and purified a chimera of the FP and TMD, connected
by a Gly-Lys linker, and measured the chemical shifts and interdomain
contacts of the protein in several lipid membranes. The FP–TMD
chimera exhibits α-helical chemical shifts in all the membranes
examined and does not cause strong curvature of lamellar membranes
or membranes with negative spontaneous curvature. These properties
differ qualitatively from those of the separate peptides, indicating
that the FP and TMD interact with each other in the lipid membrane.
However, no 13C–13C cross peaks are observed
in two-dimensional correlation spectra, suggesting that the two helices
are not tightly associated. These results suggest that the ectodomain
six-helix bundle does not propagate into the membrane to the two hydrophobic
termini. However, the loosely associated FP and TMD helices are found
to generate significant negative Gaussian curvature to membranes that
possess spontaneous positive curvature, consistent with the notion
that the FP–TMD assembly may facilitate the transition of the
membrane from hemifusion intermediates to the fusion pore
The Influenza M2 Cytoplasmic Tail Changes the Proton-Exchange Equilibria and the Backbone Conformation of the Transmembrane Histidine Residue to Facilitate Proton Conduction
Full text linkNational Institutes of Health (U.S.) (GM088204
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Conformation and Lipid Interaction of the Fusion Peptide of the Paramyxovirus PIV5 in Anionic and Negative-Curvature Membranes from Solid-State NMR
No full textABSTRACT: Viral fusion proteins catalyze the merger of the virus envelope and the target cell membrane through multiple steps of protein conformational changes. The fusion peptide do-main of these proteins is important for membrane fusion, but how it causes membrane curvature and dehydration is still poorly understood. We now use solid-state NMR spectroscopy to investigate the conformation, topology, and lipid and water interactions of the fusion peptide of the PIV5 virus F protein in three lipid membranes, POPC/POPG, DOPC/DOPG, and DOPE. These membranes allow us to investigate the effects of lipid chain disorder, membrane surface charge, and intrinsic negative curvature on the fusion peptide structure. Chemical shifts and spin diffusion data indicate that the PIV5 fusion peptide is inserted into all three membranes but adopts distinct conformations: it is fully α-helical in the POPC/POPG membrane, adopts a mixed strand/helix conformation in the DOPC/DOPG membrane, and is primarily a β-strand in the DOPE membrane. 31P NMR spectra show that the peptide retains the lamellar structure and hydration of the two anionic membranes. However, it dehydrates the DOPE membrane, destabilizes its inverted hexagonal phase, and creates an isotropic phase that is mos
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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