Charge detection mass spectrometry (CD-MS) is used to monitor the dissociation of large (300 kDa to 20 MDa) protein complexes in droplets heated with a 10.6 μm CO laser. In this approach, electrospray ionization (ESI) is used to produce charged droplets containing macromolecular complexes. As the droplets travel from the ESI capillary tip to the entrance of the CD-MS instrument, they pass through a variable-power laser field, where they are rapidly heated and dissociate to produce fragments. The approach is illustrated for three model systems: glutamate dehydrogenase (GDH), a 334 kDa hexameric protein complex, which dissociates into protein monomers, dimers, and tetramers; the ∼3 MDa = 3, and ∼4 MDa = 4 hepatitis B virus VLPs (virus-like particles) that produce a distribution of protein dimer clusters; and the ∼20 MDa = 7 human papillomavirus VLP, which dissociates primarily into small capsid protein clusters that are not well-resolved by CD-MS. The fragments produced by in-droplet activation provide information that is useful for characterizing the structures of the intact antecedent complexes. A discussion of the advantages and current limitations of this approach is presented.
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http://dx.doi.org/10.1021/acs.analchem.4c06038 | DOI Listing |
Heliyon
January 2025
Department of Chemical Engineering, Quchan Branch, Islamic Azad University, Quchan, Iran.
An interface can be delicately designed using interactions between nanoparticles and surfactants by controlling surface properties such as activity and charge equilibrium. This study seeks to provide insights into how surfactant concentration impacts the stability and dynamics of nanoparticle-surfactant interfaces, with potential applications in material science and interface engineering. This study investigates the interactions between Graphene Function (Gr, Graphene function in this text refers to functionalizing the graphene sheets with -COOH groups via acidic reactions.
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January 2025
Division for Neurogeriatrics, Centre for Alzheimer Research, Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
Copy number variation (CNV) of the amyloid-β precursor protein gene (APP) is a known cause of autosomal dominant Alzheimer disease (ADAD), but de novo genetic variants causing ADAD are rare. We report a mother and daughter with neuropathologically confirmed definite Alzheimer disease (AD) and extensive cerebral amyloid angiopathy (CAA). Copy number analysis identified an increased number of APP copies and genome sequencing (GS) revealed the underlying complex genomic rearrangement (CGR) including a triplication of APP with two unique breakpoint junctions (BPJs).
View Article and Find Full Text PDFUltrason Sonochem
January 2025
School of Engineering Computing and Mathematics, Oxford Brookes University, Oxford, UK; Department of Materials, University of Oxford, Oxford, UK.
This study experimentally investigates the role of cavitation-induced shock waves in initiating and destabilizing capillary (surface) waves on a droplet surface, preceding atomization. Acoustic emissions and interfacial wave dynamics were simultaneously monitored in droplets of different liquids (water, isopropyl alcohol and glycerol), using a calibrated fiber-optic hydrophone and high-speed imaging. Spectral analysis of the hydrophone data revealed distinct subharmonic frequency peaks in the acoustic spectrum correlated with the wavelength of capillary waves, which were optically captured during the onset of atomization from the repetitive imploding bubbles.
View Article and Find Full Text PDFRSC Adv
January 2025
Jiangsu Key Laboratory of Sericultural Biology and Animal Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology Zhenjiang 212100 China
: in the twenty-first century, the emergence of COVID-19 as a highly transmissible pandemic disease caused by SARS-CoV-2 posed a significant threat to humanity. : the disease spreads through small respiratory droplets, necessitating the use of various compounds for treatment, with alkaloids being recognized as particularly crucial owing to their diverse pharmaceutical properties. : in this study, a dataset comprising 100 natural alkaloids obtained from the literature was transformed into 2D chemical structures using Chem Draw 19.
View Article and Find Full Text PDFNat Commun
January 2025
Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ, USA.
Colonies of the social bacterium Myxococcus xanthus go through a morphological transition from a thin colony of cells to three-dimensional droplet-like fruiting bodies as a strategy to survive starvation. The biological pathways that control the decision to form a fruiting body have been studied extensively. However, the mechanical events that trigger the creation of multiple cell layers and give rise to droplet formation remain poorly understood.
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