Effects of ionic strength on SAXS data for proteins revealed by molecular dynamics simulations

2011 ◽  
Vol 134 (2) ◽  
pp. 025102 ◽  
Author(s):  
Tomotaka Oroguchi ◽  
Mitsunori Ikeguchi
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Franco-Ulloa ◽  
Giuseppina Tatulli ◽  
Sigbjørn Løland Bore ◽  
Mauro Moglianetti ◽  
Pier Paolo Pompa ◽  
...  

Abstract The fundamental interactions underlying citrate-mediated chemical stability of metal nanoparticles, and their surface characteristics dictating particle dispersion/aggregation in aqueous solutions, are largely unclear. Here, we developed a theoretical model to estimate the stoichiometry of small, charged ligands (like citrate) chemisorbed onto spherical metallic nanoparticles and coupled it with atomistic molecular dynamics simulations to define the uncovered solvent-accessible surface area of the nanoparticle. Then, we integrated coarse-grained molecular dynamics simulations and two-body free energy calculations to define dispersion state phase diagrams for charged metal nanoparticles in a range of medium’s ionic strength, a known trigger for aggregation. Ultraviolet-visible spectroscopy experiments of citrate-capped nanocolloids validated our predictions and extended our results to nanoparticles up to 35 nm. Altogether, our results disclose a complex interplay between the particle size, its surface charge density, and the ionic strength of the medium, which ultimately clarifies how these variables impact colloidal stability.


Author(s):  
Bruna M. Soares ◽  
Pedro T. Sodré ◽  
Andrea M. Aguilar ◽  
Barbara B. Gerbelli ◽  
Juliane N. B. D. Pelin ◽  
...  

Guanidiniocarbonyl pyrrole (GCP) conjugated lipopeptides improve aldol reaction catalysis by enhanced the molecules packing parameter, as shown by SAXS data and molecular dynamics simulations.


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