Despite tremendous efforts, the exact structure of SARS-CoV-2 and related betacoronaviruses remains elusive. SARS-CoV-2 envelope is a key structural component of the virion that encapsulates viral RNA. It is composed of three structural proteins, spike, membrane (M), and envelope, which interact with each other and with the lipids acquired from the host membranes. Here, we developed and applied an integrative multi-scale computational approach to model the envelope structure of SARS-CoV-2 with near atomistic detail, focusing on studying the dynamic nature and molecular interactions of its most abundant, but largely understudied, M protein. The molecular dynamics simulations allowed us to test the envelope stability under different configurations and revealed that the M dimers agglomerated into large, filament-like, macromolecular assemblies with distinct molecular patterns. These results are in good agreement with current experimental data, demonstrating a generic and versatile approach to model the structure of a virus de novo.
DOCUMENT
Understanding taste is key for optimizing the palatability of seaweeds and other non-animal-based foods rich in protein. The lingual papillae in the mouth hold taste buds with taste receptors for the five gustatory taste qualities. Each taste bud contains three distinct cell types, of which Type II cells carry various G protein-coupled receptors that can detect sweet, bitter, or umami tastants, while type III cells detect sour, and likely salty stimuli. Upon ligand binding, receptor-linked intracellular heterotrimeric G proteins initiate a cascade of downstream events which activate the afferent nerve fibers for taste perception in the brain. The taste of amino acids depends on the hydrophobicity, size, charge, isoelectric point, chirality of the alpha carbon, and the functional groups on their side chains. The principal umami ingredient monosodium l-glutamate, broadly known as MSG, loses umami taste upon acetylation, esterification, or methylation, but is able to form flat configurations that bind well to the umami taste receptor. Ribonucleotides such as guanosine monophosphate and inosine monophosphate strongly enhance umami taste when l-glutamate is present. Ribonucleotides bind to the outer section of the venus flytrap domain of the receptor dimer and stabilize the closed conformation. Concentrations of glutamate, aspartate, arginate, and other compounds in food products may enhance saltiness and overall flavor. Umami ingredients may help to reduce the consumption of salts and fats in the general population and increase food consumption in the elderly.
MULTIFILE
Objective: The aim of this study was to obtain insight in specific elements influencing the use, non-use, satisfaction, and dissatisfaction of ankle foot orthoses (AFOs) and the presence of underexposed problems with respect to AFOs. Methods: A questionnaire was composed to obtain information from AFO users to investigate the variables associated with satisfaction and the relation between these variables. A specific feature of this study was the systematic analysis of the remarks made by the respondents about their AFO. Quantitative data analyses were used for analysing the satisfaction and qualitative analyses were used analysing the remarks of the respondents. A total of 211 users completed the questionnaire. Results: Our survey showed that 1 out of 15 AFOs were not used at all. About three quarters of the AFO users were satisfied and about one quarter was dissatisfied. Females and users living alone reported relatively high levels of dissatisfaction, especially in the field of dimensions, comfort, weight, safety and effectiveness. Dissatisfaction with respect to off-the-shelf AFOs for the item durability was higher than that for custom-made AFOs. In the delivery and maintenance process the items ‘maintenance’, ‘professionalism’ and ‘delivery follow-up’ were judged to be unsatisfactory. A large number of comments were made by the respondents to improve the device or process, mainly by the satisfied AFO users. These comments show that even satisfied users experience many problems and that a lot of problems of AFO users are ‘underexposed’. Conclusion: To improve user satisfaction, the user practice has to be identified as an important sub-process of the whole orthopaedic chain especially in the diagnosis and prescription, delivery tuning and maintenance, and evaluation phase.
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