Abstract:
:The effect of a transmembrane peptide on the domain structure of a two-component, two-phase lipid bilayer composed of dimyristoyl phosphatidylcholine (DMPC) and distearoyl phosphatidylcholine (DSPC) was examined by spin label electron spin resonance (ESR) spectroscopy. The peptide, pOmpA, is the hydrophobic, 25-residue signal sequence of the outer membrane protein A from Escherichia coli. Nitroxide derivatives of the phospholipid DSPC, 16-DSPCSL, and of the pOmpA signal peptide, pOmpA-IASL, were used as probes. The first-derivative lineshapes of the ESR spectra were analyzed using a normalized intensity ratio, R, that gives information on the average sizes of the disconnected fluid domains and their point of connectivity (Sankaram, M.B., D. Marsh, and T.E. Thompson. 1992. Biophys. J. 63:340-349). In the absence of the peptide, the number of fluid lipid domains does not vary with the fraction of lipid that is in the fluid phase, and phase conversion is accomplished solely by changes in the domain size. The phase boundaries of the lipid mixture remain largely unchanged by the presence of the peptide at mole fractions up to 0.02, but both the size and number of the fluid domains is changed, and the point at which they become connected is shifted to lower fractions of the fluid phase. In addition, the number of domains in the presence of the peptide no longer remains constant but increases from a domain density at low fractions of the fluid phase that is much lower than that in the absence of peptide to one that is comparable to the natural state in the absence of peptide at the point of domain connectivity. A simple model is presented for the process of domain fission, where the latter is determined by a balance between the effects of peptide concentration in the fluid domains, the line tension at the domain boundaries, and the distributional entropy of the domains.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Sankaram MB,Marsh D,Gierasch LM,Thompson TEdoi
10.1016/S0006-3495(94)80989-0subject
Has Abstractpub_date
1994-06-01 00:00:00pages
1959-68issue
6eissn
0006-3495issn
1542-0086pii
S0006-3495(94)80989-0journal_volume
66pub_type
杂志文章abstract::In this paper, we consider the effect of adding small carbohydrate solutes (small sugars) to DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) L(alpha) dispersions and the consequences on the force balance at zero osmotic pressure (maximal swelling). We show the importance of long incubations required to obtain sampl...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75388-5
更新日期:2002-01-01 00:00:00
abstract::Molecular sensors based on intramolecular Förster resonance energy transfer (FRET) have become versatile tools to monitor regulatory molecules in living tissue. However, their use is often compromised by low signal strength and excessive noise. We analyzed signal/noise (SNR) aspects of spectral FRET analysis methods, ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.07.053
更新日期:2010-10-06 00:00:00
abstract::The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeoba...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.03.031
更新日期:2014-05-06 00:00:00
abstract::Chimeric antigen receptors (CARs) have recently been approved for the treatment of hematological malignancies, but our lack of understanding of the basic mechanisms that activate these proteins has made it difficult to optimize and control CAR-based therapies. In this study, we use phosphoproteomic mass spectrometry a...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2018.08.018
更新日期:2018-09-18 00:00:00
abstract::Bipolar tetraether lipids (BTLs) are abundant in crenarchaeota, which thrive in both thermophilic and nonthermophilic environments, with wide-ranging growth temperatures (4-108°C). BTL liposomes can serve as membrane models to explore the role of BTLs in the thermal stability of the plasma membrane of crenarchaeota. I...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.09.061
更新日期:2010-11-17 00:00:00
abstract::The kinetic properties of the three taxonomic A substates of sperm whale carbonmonoxy myoglobin in 75% glycerol/buffer are studied by flash photolysis with monitoring in the infrared stretch bands of bound CO at nu(A0) approximately 1967 cm-1, nu(A1) approximately 1947 cm-1, and nu(A3) approximately 1929 cm-1 between ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79359-1
更新日期:1996-09-01 00:00:00
abstract::Small RNA-mRNA binding is an essential step in RNA interference, an important cellular regulatory process. Calculations of binding free energy have been used in binding site prediction, but the cost of stretching the mRNA loop when the small RNA-mRNA duplex forms requires further exploration. Here, using both polymer ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.12.017
更新日期:2013-01-22 00:00:00
abstract::K(ATP) channels are comprised of a pore-forming protein, Kir6.x, and the sulfonylurea receptor, SURx. Interaction of adenine nucleotides with Kir6.2 positively charged amino acids such as K185 and R201 on the C-terminus causes channel closure. Substitution of these amino acids with other positively charged residues ha...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74847-4
更新日期:2003-01-01 00:00:00
abstract::The Mie theory of scattering is used to provide new information on how changes in particle volume, with no change in dry weight, should influence light scattering for various scattering angles and particle sizes. Many biological cells (e.g., algal cells, erythrocytes) and large subcellular structures (e.g., chloroplas...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(72)86120-4
更新日期:1972-07-01 00:00:00
abstract::The mathematical model of steady-state iron kinetics in the human presented here extends the use of radioactive tracer observations in the determination of erythron maturative and proliferative behavior. Functions descriptive of that behavior appear explicitly in the model together with functions customarily measured ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(65)86750-9
更新日期:1965-11-01 00:00:00
abstract::Knowledge about the influenza fusion peptide (FP) membrane insertion mode is crucial for understanding its fusogenic mechanism. NMR and electron paramagnetic resonance experiments showed that in micelles, the FP inserted as a fixed-angle inverted V. In membranes, however, it was shown to insert as a straight α-helix (...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.04.003
更新日期:2012-05-16 00:00:00
abstract::The adult form of the nicotinic acetylcholine receptor (AChR) consists of five subunits (alpha(2)betaepsilondelta), each having four transmembrane domains (M1-M4). The atomic model of the nicotinic acetylcholine receptor shows that the pore-lining M2 domains make no extensive contacts with the rest of the transmembran...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.088757
更新日期:2007-01-01 00:00:00
abstract::Influenza A virus M2 protein is known to form acid-activated, proton-selective, amantadine-sensitive channels. We directly measured proton uptake in vesicles containing reconstituted M2 by monitoring external pH after addition of valinomycin to vesicles with 100-fold-diluted external [K(+)]. External pH typically incr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.109082
更新日期:2008-01-15 00:00:00
abstract::The opening of basepairs plays a key role in DNA replication and transcription, and in the action of DNA repair and modification enzymes. In this article, we have used proton exchange to define the energetics of the pathways for basepair opening in two DNA 17-mer duplexes. The rates of exchange of imino protons with s...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.065763
更新日期:2005-11-01 00:00:00
abstract::Based on differences between the x-ray crystal structures of ligand-bound and unbound forms, the activation of the erythropoietin receptor (EPOR) was initially proposed to involve a cross-action scissorlike motion. However, the validity of the motions involved in the scissorlike model has been recently challenged. Her...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.12.042
更新日期:2017-02-28 00:00:00
abstract::The field of computational biology has been revolutionized by recent advances in genomics. The completion of a number of genome projects, including that of the human genome, has paved the way toward a variety of challenges and opportunities in bioinformatics and biological systems engineering. One of the first challen...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74640-2
更新日期:2003-10-01 00:00:00
abstract::Polymers play an important role in many biological systems, so a fundamental understanding of their cross-links is crucial not only for the development of medicines but also for the development of biomimetic materials. The biomechanical movements of all mammals are aided by tendon fibrils. The self-organization and bi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.056747
更新日期:2005-07-01 00:00:00
abstract::The naturally occurring amino acid cysteine has often been implicated with a crucial role in maintaining protein structure and stability. An intriguing duality in the intrinsic hydrophobicity of the cysteine side chain is that it exhibits both polar as well as hydrophobic characteristics. Here, we have utilized a cyst...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.05.024
更新日期:2019-07-09 00:00:00
abstract::Gigaohm recordings have been made from glutamate receptor channels in excised, outside-out patches of collagenase-treated locust muscle membrane. The channels in the excised patches exhibit the kinetic state switching first seen in megaohm recordings from intact muscle fibers. Analysis of channel dwell time distributi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(90)82367-5
更新日期:1990-07-01 00:00:00
abstract::In an open circuit there can be no net cation flux through membranes containing only cation-selective channels, because electroneutrality must be maintained. If the channels are so narrow that water and cations cannot pass by each other, then the net water flux through those "single-file" channels that contain a catio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(81)84804-7
更新日期:1981-08-01 00:00:00
abstract::Single-stranded junctions/loops are frequently occurring structural motifs in nucleic acid structures. Due to the polyanionic nature of the nucleic acid backbone, metal ions play a crucial role in the loop stability. Here we use the tightly bound ion theory, which can account for the possible ion correlation and ensem...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.131524
更新日期:2008-07-01 00:00:00
abstract::The mechanisms that limit the speed at which striated muscles relax are poorly understood. This work presents, to our knowledge, novel simulations that show that the time course of relaxation is accelerated by interfilamentary movement resulting from series compliance; force drops faster when myosin heads move relativ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.12.024
更新日期:2016-02-02 00:00:00
abstract::Fusion is a crucial event in the infection of animal cells by enveloped viruses (e.g., HIV or influenza). Viral fusion is mediated by glycoproteins, spanning the viral envelope, which attach to a membrane surface and induce fusion of the viral envelope to the cellular membrane. Influenza fusion protein (hemagglutinin)...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78175-X
更新日期:1997-09-01 00:00:00
abstract::Fatty acid binding proteins play an important role in the transportation of fatty acids. Despite intensive studies, how fatty acids enter the protein cavity for binding is still controversial. Here, a gap-closed variant of human intestinal fatty acid binding protein was generated by mutagenesis, in which the gap is lo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.12.005
更新日期:2020-01-21 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::Most of the cellular ATP in living organisms is synthesized by the enzyme F(1)F(o)-ATP synthase. The water soluble F(1) part of the enzyme can also work in reverse and utilize the chemical energy released during ATP hydrolysis to generate mechanical motion. Despite the availability of a large amount of biochemical dat...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74650-5
更新日期:2003-10-01 00:00:00
abstract::Molecular dynamics simulations of RNA-protein complex between Escherichia coli loop E/helix IV (LE/HeIV) rRNA and L25 protein reveal a qualitative agreement between the experimental and simulated structures. The major groove of LE is a prominent rRNA cation-binding site. Divalent cations rigidify the LE major groove g...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.047126
更新日期:2004-11-01 00:00:00
abstract::The reported rates of thermal 13-cis to all-trans isomerization of the protonated Schiff base of retinal (PSBR) in solution and in bacteriorhodopsin (BR) are shown to be correlated with the red shift in the absorption maximum of the chromophore, though the linear fit is different for BR and for a model PSBR in solutio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(91)82070-7
更新日期:1991-08-01 00:00:00
abstract::The ionophore properties of magainin I, an antimicrobial and amphipathic peptide from the skin of Xenopus, were investigated in planar lipid bilayers. Circular dichroism studies, performed comparatively with alamethicin, in small or large unilamellar phospholipidic vesicles, point to a smaller proportion of alpha-heli...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82746-8
更新日期:1989-11-01 00:00:00
abstract::Large bottlebrush complexes formed from the polysaccharide hyaluronan (HA) and the proteoglycan aggrecan contribute to cartilage compression resistance and are necessary for healthy joint function. A variety of mechanical forces act on these complexes in the cartilage extracellular matrix, motivating the need for a qu...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.08.016
更新日期:2020-10-06 00:00:00