DNA-lipid complexes are of biomedical importance as delivery vectors for gene therapy. To gain insight into the interactions of DNA with zwitterionic and cationic (dimyristoyltrimethylammonium propane (DMTAP)) lipids, we have used coarse-grained molecular dynamics simulations to study the self-assembly of DPPC and DPPC/DMTAP lipid bilayers in the presence of a DNA dodecamer. We observed the spontaneous formation of lipid bilayers from initial systems containing randomly placed lipids, water-counterions and DNA. In both the DPPC and DPPC/DMTAP simulations, the DNA molecule is located at the water-lipid headgroup interface, lying approximately parallel to the plane of the bilayer. We have also calculated the potential of mean force for transferring a DNA dodecamer through a DPPC/DMTAP bilayer. A high energetic barrier to DNA insertion into the hydrophobic core of the bilayer is observed. The DNA adopts a transmembrane orientation only in this region. Local bilayer deformation in the vicinity of the DNA molecule is observed, largely as a result of the DNA-DMTAP headgroup attraction.
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http://dx.doi.org/10.1098/rsif.2008.0239.focus | DOI Listing |
Langmuir
January 2025
Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, United States.
Biological memory is the ability to develop, retain, and retrieve information over time. Currently, it is widely accepted that memories are stored in synapses (i.e.
View Article and Find Full Text PDFLangmuir
January 2025
Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112-0850, United States.
Modification of silica interfaces by covalent attachment of functional ligands is a primary means of controlling the interfacial chemistry of porous silicas used in separations, environmental cleanup, and biosensing. Recently, modification of hydrophobic, -alkyl-silane-functionalized interfaces has been achieved through self-assembly of zwitterionic phospholipids or mixed-charged surfactants to form "hybrid bilayers", producing interfaces that mimic lipid-bilayer partitioning and provide shape-selective partitioning of aromatic hydrocarbons. Charged headgroups, however, introduce electrostatic interactions that strongly influence the retention of ionizable solutes and require careful control over pH and ionic strength in the solution phase.
View Article and Find Full Text PDFLangmuir
January 2025
School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Alkylphospholipids are single-chain lipid amphiphiles that possess clinically relevant biological activities driven by membrane-destabilizing interactions. Subtle variations in alkylphospholipid structure can lead to significant differences in their biological effects, yet corresponding membrane interactions remain underexplored. Herein, we employed the quartz crystal microbalance-dissipation (QCM-D) technique to characterize the real-time membrane interactions of three alkylphospholipids-edelfosine, miltefosine, and perifosine-on supported lipid bilayers with varying cholesterol fractions.
View Article and Find Full Text PDFFEBS Open Bio
January 2025
Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Germany.
Neurotransmitter release is triggered in microseconds by the two C domains of the Ca sensor synaptotagmin-1 and by SNARE complexes, which form four-helix bundles that bridge the vesicle and plasma membranes. The synaptotagmin-1 CB domain binds to the SNARE complex via a 'primary interface', but the mechanism that couples Ca-sensing to membrane fusion is unknown. Widespread models postulate that the synaptotagmin-1 Ca-binding loops accelerate membrane fusion by inducing membrane curvature, perturbing lipid bilayers or helping bridge the membranes, but these models do not seem compatible with SNARE binding through the primary interface, which orients the Ca-binding loops away from the fusion site.
View Article and Find Full Text PDFNeuron
January 2025
Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA. Electronic address:
Neurexin cell-adhesion molecules regulate synapse development and function by recruiting synaptic components. Here, we uncover a mechanism for presynaptic assembly that precedes neurexin recruitment, mediated by interactions between cytosolic proteins and membrane phospholipids. Developmental imaging in C.
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