Abstract:
:We have monitored the organization and dynamics of the hemolytic peptide melittin in membranes containing cholesterol by utilizing the intrinsic fluorescence properties of its functionally important sole tryptophan residue and circular dichroism spectroscopy. The significance of this study is based on the fact that the natural target for melittin is the erythrocyte membrane, which contains high amounts of cholesterol. Our results show that the presence of cholesterol inhibits melittin-induced leakage of lipid vesicles and the extent of inhibition appears to be dependent on the concentration of membrane cholesterol. The presence of cholesterol is also shown to reduce binding of melittin to membranes. Our results show that fluorescence parameters such as intensity, emission maximum, and lifetime of membrane-bound melittin indicate a change in polarity in the immediate vicinity of the tryptophan residue probably due to increased water penetration in presence of cholesterol. This is supported by results from fluorescence quenching experiments using acrylamide as the quencher. Membrane penetration depth analysis by the parallax method shows that the melittin tryptophan is localized at a relatively shallow depth in membranes containing cholesterol. Analysis of energy transfer results using melittin tryptophan (donor) and dehydroergosterol (acceptor) indicates that dehydroergosterol is not randomly distributed and is preferentially localized around the tryptophan residue of membrane-bound melittin, even at the low concentrations used. Taken together, our results are relevant in understanding the interaction of melittin with membranes in general, and with cholesterol-containing membranes in particular, with possible relevance to its interaction with the erythrocyte membrane.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Raghuraman H,Chattopadhyay Adoi
10.1529/biophysj.104.043596subject
Has Abstractpub_date
2004-10-01 00:00:00pages
2419-32issue
4eissn
0006-3495issn
1542-0086pii
S0006-3495(04)73715-7journal_volume
87pub_type
杂志文章abstract::We describe a statistical technique, the joint peristimulus time (PST) scatter diagram, for the analysis of data from simultaneously recorded neurons subjected to repeated stimulation. Distinguishable features in the scatter diagram are related to effects of the stimulus on the observed neurons and to functional relat...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(72)86097-1
更新日期:1972-05-01 00:00:00
abstract::The distribution of low concentrations of ganglioside GM1 in L-alpha-dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol monolayers supported on mica has been studied using atomic force microscopy (AFM). The monolayers studied correspond to a pure gel phase and a mixture of liquid-expanded (LE) and liquid-conde...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76516-7
更新日期:2000-11-01 00:00:00
abstract::Normally, isothermal titration calorimetry (ITC) is used to study binding reactions between two different biomolecules. Self-association processes leading to homo-oligomeric complexes have usually not been studied by ITC; instead, methods such as spectroscopy and analytical ultracentrifugation, which only provide affi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.067223
更新日期:2005-11-01 00:00:00
abstract::Simulations of two distinct systems, one a planar bilayer, the other the inverse hexagonal phase, indicate consistent mechanical properties and curvature preferences, with single DOPE leaflets having a spontaneous curvature, R0 = -26 Å (experimentally ~ -29.2 Å) and DOPC leaflets preferring to be approximately flat (R...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.03.048
更新日期:2013-05-21 00:00:00
abstract::There is increasing evidence that UVA radiation, which makes up approximately 95% of the solar UV light reaching the Earth's surface and is also commonly used for cosmetic purposes, is genotoxic. However, in contrast to UVC and UVB, the mechanisms by which UVA produces various DNA lesions are still unclear. In additio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.10.030
更新日期:2009-02-01 00:00:00
abstract::Pressure versus distance relations have been obtained for solid (gel) and neat (liquid-crystalline) phase uncharged lipid bilayers by the use of x-ray diffraction analysis of osmotically stressed monoglyceride aqueous dispersions and multilayers. For solid phase monoelaidin bilayers, the interbilayer repulsive pressur...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82888-7
更新日期:1989-05-01 00:00:00
abstract::We developed a model of the rat ventricular myocyte at room temperature to predict the relative effects of different mechanisms on the cause of the slow increase in force in response to a step change in muscle length. We performed simulations in the presence of stretch-dependent increases in flux through the Na(+)-H(+...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.095463
更新日期:2007-06-01 00:00:00
abstract::Proton translocation activity of bacteriorhodopsin mutants lacking the proton acceptor Asp-85 was investigated using the black lipid membrane technique. Mutants D85N, D85T, and D85,96N were constructed and homologously expressed in Halobacterium salinarium to yield a membrane fraction with a buoyant density of 1.18 g/...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80642-3
更新日期:1994-10-01 00:00:00
abstract::Photosystem II contains two well-characterized tyrosine radicals, D(.) and Z(.). Z is an electron carrier between the primary chlorophyll donor and the manganese catalytic site and is essential for enzymatic function. On the other hand, D forms a stable radical with no known role in oxygen evolution. D(.) and Z(.) giv...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79394-3
更新日期:1996-10-01 00:00:00
abstract::Why is the spine of a neuron so small that it can contain only small numbers of molecules and reactions inevitably become stochastic? We previously showed that, despite such noisy conditions, the spine exhibits robust, sensitive, and efficient features of information transfer using the probability of Ca2+ increase; ho...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.12.043
更新日期:2017-02-28 00:00:00
abstract::Myofilament length-dependent activation is a universal property of striated muscle, yet the molecular mechanisms that underlie this phenomenon are incompletely understood. Additionally, the rate by which sarcomere length (SL) is sensed and then transduced to form length-dependent activation is unknown. Here, using iso...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.05.034
更新日期:2012-07-03 00:00:00
abstract::The effect of S-methylating cysteine-102 (cys-102) (SH----SSCH3) of yeast isozyme-1 (iso-1) ferricytochrome c has been studied using proton NMR spectroscopy. COSY, NOESY, and one-dimensional nuclear Overhauser effect (NOE) difference spectroscopies have all been used. The NMR spectrum of this derivative is very simila...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82352-3
更新日期:1990-07-01 00:00:00
abstract::Model compound studies in the literature show how Hofmeister ion interactions affect protein stability. Although model compound results are typically obtained as salting-out constants, they can be used to find out how the interactions affect protein stability. The null point in the Hofmeister series, which divides pro...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79404-3
更新日期:1996-10-01 00:00:00
abstract::We measured the exocytotic response induced by flash photolysis of caged compounds in isolated mast cells and chromaffin cells. Vesicle fusion was measured by monitoring the cell membrane capacitance. The release of vesicular contents was followed by amperometry. In response to a GTP gamma S stimulus we found that the...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79315-3
更新日期:1996-08-01 00:00:00
abstract::Reverberating spontaneous synchronized brain activity is believed to play an important role in neural information processing. Whether and how external stimuli can influence this spontaneous activity is poorly understood. Because periodic synchronized network activity is also prominent in in vitro neuronal cultures, we...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.112730
更新日期:2008-06-01 00:00:00
abstract::Quantum chemical computations using the ab initio molecular orbital (MO) method have been performed to investigate the molecular switching mechanism of Ras protein p21, which has an important role in intracellular signal cascades. Lys(16) was demonstrated to be crucial to the function of Ras p21, and the hydrolysis of...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77159-6
更新日期:1999-12-01 00:00:00
abstract::Primary embryonic chick cells have been evaluated on the basis of their capacity to repair photochemical lesions produced in the deoxyribonucleic acid (DNA) by ultraviolet (UV) radiation. The fate of one prominent class of UV photoproducts, cyclobutane pyrimidine dimers, was monitored by an in vitro enzymatic assay. U...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(74)85926-6
更新日期:1974-06-01 00:00:00
abstract::In adherent and motile neutrophils NAD(P)H concentration, flavoprotein redox potential, and production of reactive oxygen species and nitric oxide, are all periodic and exhibit defined phase relationships to an underlying metabolic oscillation of approximately 20 s. Utilizing fluorescence microscopy, we have shown in ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.056663
更新日期:2005-05-01 00:00:00
abstract::Here it is reported that aggrecan, the highly negatively charged macromolecule in the cartilage extracellular matrix, undergoes Ca(2+)-mediated self-adhesion after static compression even in the presence of strong electrostatic repulsion in physiological-like solution conditions. Aggrecan was chemically end-attached o...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.128389
更新日期:2008-11-15 00:00:00
abstract::Biological cells embedded in fibrous matrices have been observed to form intercellular bands of dense and aligned fibers through which they mechanically interact over long distances. Such matrix-mediated cellular interactions have been shown to regulate various biological processes. This study aimed to explore the eff...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.07.036
更新日期:2018-10-02 00:00:00
abstract::We present a molecular model of a chromatophore vesicle from Rhodobacter sphaeroides. These vesicles are ideal benchmark systems for molecular and systemic simulations, because they have been well studied, they are small, and they are naturally separated from their cellular environment. To set up a photosynthetic chai...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.067561
更新日期:2006-08-01 00:00:00
abstract::The energetics of phospholipid aggregation depend on the apparent water-accessible apolar surface area (ASAap), ordering effects of the chains, and headgroup interactions. We quantify the enthalpy and entropy of these interactions separately. For that purpose, the thermodynamics of micelle formation of lysophosphatidy...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)76012-2
更新日期:2001-01-01 00:00:00
abstract::Shock waves are used clinically for breaking kidney stones and treating musculoskeletal indications. The mechanisms by which shock waves interact with tissue are still not well understood. Here, ultra-high-speed imaging was used to visualize the deformation of individual cells embedded in a tissue-mimicking phantom wh...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.09.042
更新日期:2018-03-27 00:00:00
abstract::The rat connexin40 gap junction channel is permeable to monovalent cations including tetramethylammonium and tetraethylammonium ions. Larger tetraalkyammonium (TAA(+)) ions beginning with tetrabutylammonium (TBA(+)) reduced KCl junctional currents disproportionately. Ionic blockade by tetrapentylammonium (TPeA(+)) and...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75960-7
更新日期:2001-12-01 00:00:00
abstract::Two independent methods, induced osmosis and solvent drag, were used to determine the reflection coefficients for NaCl (sigma NaCl) in brush border and basolateral membrane vesicles isolated from rabbit proximal tubule. In the induced osmosis method, vesicles loaded with sucrose were subjected to varying inward NaCl g...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82920-0
更新日期:1989-06-01 00:00:00
abstract::A sequence determinant of reduction potentials is reported for bacterial [4Fe-4S]-type ferredoxins. The residue that is four residues C-terminal to the fourth ligand of either cluster is generally an alanine or a cysteine. In five experimental ferredoxin structures, the cysteine has the same structural orientation rel...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(01)75726-8
更新日期:2001-08-01 00:00:00
abstract::Deuterium NMR spectroscopy was used to study how the positioning of a dimerization motif within a transbilayer polypeptide influences its orientation and dynamics in bilayers. Three polypeptide variants comprising glycophorin A transmembrane (GpATM) dimerization motifs incorporated into lysine-terminated poly-leucine-...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.12.3725
更新日期:2011-02-02 00:00:00
abstract::Carbonic anhydrase (CA) is a thoroughly studied enzyme. Its primary role is the rapid interconversion of carbon dioxide and bicarbonate in the cells, where carbon dioxide is produced, and in the lungs, where it is released from the blood. At the same time, it regulates pH homeostasis. The inhibitory function of sulfon...
journal_title:Biophysical journal
pub_type: 杂志文章,评审
doi:10.1016/j.bpj.2020.08.020
更新日期:2020-10-06 00:00:00
abstract::In recent years, optical sensors for tracking neural activity have been developed and offer great utility. However, developing microscopy techniques that have several kHz bandwidth necessary to reliably capture optically reported action potentials (APs) at multiple locations in parallel remains a significant challenge...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.12.005
更新日期:2015-02-03 00:00:00
abstract::Each gating mechanism controlling permeability in a membrane may be influenced by only a few charge binding sites on the membrane surface, so that fluctuations in the occupancy of these sites are important. Tow extreme cases arise. (a) The time scale of these fluctuations is much shorter than the gating time constant....
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(78)85426-5
更新日期:1978-12-01 00:00:00