Amphotericin B (AmB) is an effective but toxic antifungal drug, known to increase the permeability of the cell membrane, presumably by assembling into transmembrane pores in a sterol-dependent manner. The aggregation of AmB molecules in a phospholipid bilayer is, thus, crucial for the drug's activity. To provide an insight into the molecular nature of this process, here, we report an atomistic molecular dynamics simulation study of AmB head-to-head dimerization in a phospholipid bilayer, a possible early stage of aggregation. To compare the effect of sterols on the thermodynamics of aggregation and the architecture of the resulting AmB-AmB complexes, free energy profiles for the dimerization in ergosterol- or cholesterol-containing and sterol-free membranes are derived from the simulations. These profiles demonstrate that although AmB dimers are formed in all the systems studied, they are significantly less favorable in the bilayer with ergosterol than in the cholesterol-containing or sterol-free ones. We investigate the structural and energetic determinants of this difference and discuss its consequences for the AmB mechanism of action.
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http://dx.doi.org/10.1016/j.bpj.2013.02.029 | DOI Listing |
J Exp Biol
January 2025
Ornis italica, Rome, Italy.
Rapid reduction of body size in populations responding to global warming suggests the involvement of temperature-dependent physiological adjustments during growth, such as mitochondrial alterations, in the efficiency of producing metabolic energy, a process that is poorly explored, especially in endotherms. Here, we examined the mitochondrial metabolism and proteomic profile of red blood cells in relation to body size and cellular energetics in nestling shearwaters (Calonectris diomedea) developing at different natural temperatures. We found that nestlings of warmer nests had lighter bodies and smaller beaks at fledging.
View Article and Find Full Text PDFJACS Au
January 2025
Department of Physics, Freie Universität Berlin, Arnimallee 14, Berlin 14195, Germany.
Interactions of polyelectrolytes (PEs) with proteins play a crucial role in numerous biological processes, such as the internalization of virus particles into host cells. Although docking, machine learning methods, and molecular dynamics (MD) simulations are utilized to estimate binding poses and binding free energies of small-molecule drugs to proteins, quantitative prediction of the binding thermodynamics of PE-based drugs presents a significant obstacle in computer-aided drug design. This is due to the sluggish dynamics of PEs caused by their size and strong charge-charge correlations.
View Article and Find Full Text PDFJACS Au
January 2025
School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
Mechanochemistry and mechanocatalysis are gaining increasing attention as environmentally friendly chemical processes because of their solvent-free nature and scalability. Significant effort has been devoted for studying continuum-scale phenomena in mechanochemistry, such as temperature and pressure gradients, but the atomic-scale mechanisms remain relatively unexplored. In this work, we focus on the mechanochemical reduction of MoO as a case study.
View Article and Find Full Text PDFJACS Au
January 2025
Department of Chemistry and Industrial Chemistry, University of Pisa, 56124 Pisa, Italy.
Naturally occurring photoenzymes are rare in nature, but among them, fatty acid photodecarboxylases derived from (FAPs) have emerged as promising photobiocatalysts capable of performing the redox-neutral, light-induced decarboxylation of free fatty acids (FAs) into C1-shortened alka(e)nes. Using a hybrid QM/MM approach combined with a polarizable embedding scheme, we identify the structural changes of the active site and determine the energetic landscape of the forward electron transfer (fET) from the FA substrate to the excited flavin adenine dinucleotide. We obtain a charge-transfer diradical structure where a water molecule rearranges spontaneously to form a H-bond interaction with the excited flavin, while the FA's carboxylate group twists and migrates away from it.
View Article and Find Full Text PDFCurr Dev Nutr
October 2024
Center for Nutrition, Healthy Lifestyle and Disease Prevention, Loma Linda University School of Public Health, Loma Linda, CA, United States.
Background: Avocado intake has been associated with improvements in diet quality. Whether this response is because of avocado intake, , or combined with a food and/or nutrient displacement (D) has yet to be determined.
Objectives: This secondary analysis, conducted using dietary data from the Habitual Diet and Avocado Trial, sought to assess the effect of consuming a large avocado (168 g, 281 kcal) daily in the avocado-supplemented diet (AD) group compared with the habitual diet (HD) group on food and nutrient D.
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