2,037 research outputs found
Lipid bilayer composition influences the activity of the antimicrobial peptide dermcidin channel.
No full textAntimicrobial peptides (AMPs) carry great potential as new antibiotics against "superbugs." Dermcidin (DCD), a broad-spectrum AMP in human sweat, has been recently crystallized in its oligomeric state and showed channel-like properties. In this work, we performed multiscale molecular dynamics simulations to study how the membrane composition influences the behavior of a transmembrane pore formed by the DCD oligomer in the hope of revealing the origin of the membrane selectivity of this AMP toward bacteria. Our results indicate that bilayers composed of various lipids (DMPC, DPPC, and DSPC) with different thicknesses result in different orientations of the DCD oligomer when embedded in lipid bilayers. The thicker the bilayer, the less tilted the channel. Cholesterol makes the bilayers more rigid and thicker, which also affects the orientation of the channel. Furthermore, we observed that the predicted conductance of the channel from computational electrophysiology simulations is related to its orientation in the lipid bilayer: the larger the tilt, the larger the conductance. Our results indicate that the membrane composition has a significant influence on the activity of the DCD channel, with thicker, cholesterol-rich membranes showing lower conductance than that of thinner membranes
Essential dynamics of reversible peptide folding: Memory-free conformational dynamics governed by internal hydrogen bonds
No full textA principal component analysis has been applied on equilibrium simulations of a beta -heptapeptide that shows reversible folding in a methanol solution. The analysis shows that the configurational space contains only three dense sub-states. These states of relatively low free energy correspond to the "native" left-handed helix, a partly helical intermediate, and a hairpin-like structure. The collection of unfolded conformations form a relatively diffuse cloud with little substructure, Internal hydrogen-bonding energies were found to correlate well with the degree of folding. The native helical structure folds from the N terminus; the transition from the major folding intermediate to the native helical structure involves the formation of the two most C-terminal backbone hydrogen bonds. A four-state Markov model was found to describe transition frequencies between the conformational states within error limits, indicating that memory-effects are negligible beyond the nanosecond time-scale. The dominant native state fluctuations were found to be very similar to unfolding motions, suggesting that unfolding pathways can be inferred from fluctuations in the native state. The low-dimensional essential subspace, describing 69% of the collective atomic fluctuations, was found to converge at time-scales of the order of one nanosecond at all temperatures investigated, whereas folding/unfolding takes place at significantly longer time-scales, even above the melting temperature. (C) 2001 Academic Press
Coronary anatomy in congenital heart disease: the important contributions of Professor Dr. Adriana Gittenberger-de Groot
No full textThe contributions of Professor Dr. Adriana Gittenberger-de Groot in relation to coronary artery development and classification are described from the viewpoint of a pediatric cardiac surgeon.Thoracic Surger
Structure and Flexibility ofStreptococcus agalactiaeHyaluronate Lyase Complex with Its Substrate
No full text
Digitalisering bij bedrijven en de relatie met export, productiviteit en werkgelegenheid
No full textEen groot deel van het bedrijfsleven maakt momenteel een digitale transformatie door.
Digitalisering beïnvloedt vandaag de dag zo goed als alle bedrijfsprocessen. Nieuwe
technologische mogelijkheden bieden zowel kansen als uitdagingen, waar bedrijven en
hun medewerkers mee om moeten zien te gaan. Dit hoofdstuk gaat in op verschillende
vormen van digitalisering en hoe deze verband houden met het productieproces,
exportgedrag en de arbeidsvraag van bedrijven. Dit verband blijkt heel verschillend te
zijn voor verschillende toepassingen van ICT. Ook zijn er verschillen in de rol van
digitalisering tussen de industrie, dienstensector of handel en tussen het mkb en
grootbedrijf
Supplemental Material, 20171119_Supl_fig_2 - Hematological Parameters Outperform Plasma Markers in Predicting Long-Term Mortality After Coronary Angiography
No full textSupplemental Material, 20171119_Supl_fig_2 for Hematological Parameters Outperform Plasma Markers in Predicting Long-Term Mortality After Coronary Angiography by Crystel M. Gijsberts, Hester M. den Ruijter, Dominique P. V. de Kleijn, Albert Huisman, Maarten ten Berg, Mark de Groot, Richard H. A. van Wijk, Folkert W. Asselbergs, Michiel Voskuil, Gerard Pasterkamp, Wouter W. van Solinge, and Imo E. Hoefer in Angiology</p
Hoe populaire en kwaliteitskranten van elkaar verschillen in verslaggeving
No full textIn welke opzichten verschilt het nieuws in ‘populaire kranten’ als AD en De Telegraaf, van het nieuws in ‘kwaliteitskranten’ als de Volkskrant en NRC Handelsblad? Mark Boukes en Rens Vliegenthart onderzochten dit voor economische berichtgeving. Wat blijkt? De verschillen zijn minder groot dan je zou denken
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