Abstract：
:To determine if hydrophobic surfactant proteins affect the stability of pulmonary surfactant monolayers at an air/water interface, the studies reported here compared the kinetics of collapse for the complete set of lipids in calf surfactant with and without the proteins. Monomolecular films spread at the surface of captive bubbles were compressed at 37 degrees C to surface pressures above 46 mN/m, at which collapse first occurred. The rate of area-compression required to maintain a constant surface pressure was measured to directly determine the rate of collapse. For films with and without the proteins, higher surface pressures initially produced faster collapse, but the rates then reached a maximum and decreased to values <0.04 min(-1) above 53 mN/m. The maximum rate for the lipids with the proteins (1.22 +/- 0.28 min(-1)) was almost twice the value for the lipids alone (0.71 +/- 0.15 min(-1)). Because small increments in surface pressure produced large shifts in the rate close to the fastest collapse, compressions at a series of constant speeds also established the threshold rate required to achieve high surface pressure as an indirect indication of the fastest collapse. Both samples produced a sharply defined threshold that occurred at slightly faster compression with the proteins present, supporting the conclusion of the direct measurements that the proteins produce a faster maximum rate of collapse. Our results indicate that at 47-53 mN/m, the hydrophobic surfactant proteins destabilize the compressed monolayers and tend to limit access to the higher surface pressures at which the lipid films become metastable.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Lhert F,Yan W,Biswas SC,Hall SBdoi
10.1529/biophysj.107.111823subject
Has Abstractpub_date
2007-12-15 00:00:00pages
4237-43issue
12eissn
0006-3495issn
1542-0086pii
S0006-3495(07)71676-4journal_volume
93pub_type
杂志文章abstract：:Recent experiments suggested that cholesterol and other lipid components of high negative spontaneous curvature facilitate membrane fusion. This is taken as evidence supporting the stalk-pore model of membrane fusion in which the lipid bilayers go through intermediate structures of high curvature. How do the high-curv...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.106.097923
更新日期：2007-04-15 00:00:00
abstract：:In most environments, such as natural aquatic systems, bacteria are found predominantly in self-organized sessile communities known as biofilms. In the presence of a significant flow, mature multispecies biofilms often develop into long filamentous structures called streamers, which can greatly influence ecosystem pro...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2011.01.065
更新日期：2011-03-16 00:00:00
abstract：:In the plant blue-light sensor phototropin, illumination of the chromophoric LOV domains causes activation of the serine/threonine kinase domain. Flavin mononucleotide (FMN) is a chromophore molecule in the two LOV domains (LOV1 and LOV2), but only LOV2 is responsible for kinase activation. Previous studies reported a...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2008.12.3924
更新日期：2009-04-08 00:00:00
abstract：:Rearrangement of tertiary structure in response to mechanical force (termed tertiary structure elasticity) in the tandem Ig chain is the first mode of elastic response for muscle protein titin. Tertiary structure elasticity occurs at low stretching forces (few tens of pN), and was described at atomic resolution in a r...
journal_title：Biophysical journal
pub_type： 信件
doi：10.1016/j.bpj.2011.01.019
更新日期：2011-02-16 00:00:00
abstract：:A model for the Na-K exchange pump was applied to data on Na(+)-loaded frog sartorius muscle, and was used to relate the rate of adenosine triphosphate (ATP) hydrolysis to the electrical properties of the cell membrane. Membrane hyperpolarization was considered to arise from an electrical current which was produced by...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(71)86243-4
更新日期：1971-08-01 00:00:00
abstract：:The switch 1 region of myosin forms a lid over the nucleotide phosphates as part of a structure known as the phosphate-tube. The homologous region in kinesin-family motors is more open, not interacting with the nucleotide. We used molecular dynamics (MD) simulations to examine a possible displacement of switch 1 of th...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(01)76092-4
更新日期：2001-03-01 00:00:00
abstract：:Atomic force microscopy (AFM) is used to study mechanical properties of biological materials at submicron length scales. However, such samples are often structurally heterogeneous even at the local level, with different regions having distinct mechanical properties. Physical or chemical disruption can isolate individu...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2018.04.036
更新日期：2018-06-05 00:00:00
abstract：:The mechanosensitive channel of large conductance (MscL) belongs to a family of transmembrane channel proteins in bacteria and functions as a safety valve that relieves the turgor pressure produced by osmotic downshock. MscL gating can be triggered solely by stretching of the membrane. This work reports an effort to u...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.107.109850
更新日期：2008-05-01 00:00:00
abstract：:In the context of reduced protein models, Monte Carlo simulations of three de novo designed helical proteins (four-member helical bundle) were performed. At low temperatures, for all proteins under consideration, protein-like folds having different topologies were obtained from random starting conformations. These sim...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(98)77497-1
更新日期：1998-07-01 00:00:00
abstract：:Cells within fibrocartilaginous tissues, including chondrocytes and fibroblasts of the meniscus, ligament, and tendon, regulate cell biosynthesis in response to local mechanical stimuli. The processes by which an applied mechanical load is transferred through the extracellular matrix to the environment of a cell are n...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.107.126938
更新日期：2008-08-01 00:00:00
abstract：:A ternary lipid mixture of palmitoyl-oleoyl-phosphatidylcholine (POPC), palmitoyl-erythro-sphingosylphosphorylcholine (PSM), and cholesterol at a mixing ratio of 37.5:37.5:25 mol/mol/mol was characterized using fluorescence microscopy, (2)H NMR, and electron paramagnetic resonance spectroscopy. The synthetic PSM provi...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.107.112904
更新日期：2008-04-01 00:00:00
abstract：:Embryonic and adult fibroblasts can be returned to pluripotency by the expression of reprogramming genes. Multiple lines of evidence suggest that these human induced pluripotent stem (hiPS) cells and human embryonic stem (hES) cells are behaviorally, karyotypically, and morphologically similar. Here we sought to deter...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2010.10.007
更新日期：2010-12-01 00:00:00
abstract：:The refractive indices, water content, and volume of wet-spun films of Na-hyaluronate have been measured as a function of relative humidity (rh). These data are used with the Lorentz-Lorenz formula to determine the optical polarizabilities of Na-hyaluronate parallel and perpendicular to the helical axis. The analysis ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(92)81604-1
更新日期：1992-08-01 00:00:00
abstract：:The auxiliary β subunit plays an important role in the regulation of voltage-gated calcium (CaV) channels. Recently, it was revealed that β2e associates with the plasma membrane through an electrostatic interaction between N-terminal basic residues and anionic phospholipids. However, a molecular-level understanding of...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2015.07.040
更新日期：2015-09-01 00:00:00
abstract：:Cis-parinaric acid (PA) binds to a hydrophobic pocket formed between the heavy chain of myosin subfragment-1 (S1) and the 41-residue N-terminal of essential light chain 1 (A1). The binding is strong (Ka = 5.6 x 10(7) M-1) and rigid (polarization = 0.334). PA does not bind to myofibrils in which A1 has been extracted o...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(97)78871-4
更新日期：1997-05-01 00:00:00
abstract：:The molecular weight of single-stranded DNA from the slime mold Physarum polycephalum has been determined by alkaline gradient centrifugation. The average molecular weight during DNA synthesis ( approximately 1.5 x 10(7) D) is less than that observed in nonsynthetic periods ( approximately 4 x 10(7) D). On the basis o...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(67)86590-1
更新日期：1967-05-01 00:00:00
abstract：:Can individual cells, including live cells, be imaged using hard x rays? Common wisdom until now required sophisticated staining techniques for this task. We show instead that individual cells and cell details can be detected in culture solution and tissues with no staining and no other contrast-enhancing preparation....
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.103.034991
更新日期：2004-12-01 00:00:00
abstract：:Sodium perchlorate salt (NaClO(4)) is commonly used as an internal intensity standard in ultraviolet resonance Raman (UVRR) spectroscopy experiments. It is well known that NaClO(4) can have profound effects on peptide stability. The impact of NaClO(4) on protein stability in UVRR experiments has not yet been fully inv...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2009.10.013
更新日期：2010-01-20 00:00:00
abstract：:Interpretation of fluorescence anisotropy decay for the case of restricted rotational diffusion often requires a model. To investigate the extent of model dependence, two models are compared: a strict cone model, in which a fluorescent probe wobbles uniformly within a cone, and a Gaussian model, where the stationary d...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(82)84692-4
更新日期：1982-02-01 00:00:00
abstract：:The application of a digital computer to the processing of data from single neurons is described. Examples from experimental data are presented to demonstrate the usefulness of certain types of computations. These methods are placed in a descriptive mathematical framework. Other easily attainable computations are sugg...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/s0006-3495(60)86872-5
更新日期：1960-09-01 00:00:00
abstract：:Cholesterol is a key component of eukaryotic membranes, but its role in cellular biology in general and in lipid rafts in particular remains controversial. Model membranes are used extensively to determine the phase behavior of ternary mixtures of cholesterol, a saturated lipid, and an unsaturated lipid with liquid-or...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2018.04.022
更新日期：2018-06-05 00:00:00
abstract：:Using CD spectroscopy, guanine tetraplex formation was studied with short DNA fragments in which cytosine residues were systematically added to runs of guanine either at the 5' or 3' ends. Potassium cations induced the G-tetraplex more easily with fragments having the guanine run at the 5' end, which is just an opposi...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(97)78235-3
更新日期：1997-10-01 00:00:00
abstract：:The fusion of a membrane-bounded vesicle with a target membrane is a key step in intracellular trafficking, exocytosis, and drug delivery. Molecular dynamics simulations have been used to study the fusion of small unilamellar vesicles composed of a dipalmitoyl-phosphatidylcholine (DPPC)/palmitic acid 1:2 mixture in at...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.106.103572
更新日期：2007-06-15 00:00:00
abstract：:Photosystem II catalyzes photosynthetic water oxidation in plants, green algae, and cyanobacteria. The manganese-containing active site cycles through a series of five oxidation states, S(n), where n refers to the number of oxidizing equivalents stored. In this report, reaction-induced Fourier transform infrared and e...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(03)74680-3
更新日期：2003-10-01 00:00:00
abstract：:Proteins fold and function in cellular environments that are crowded with other macromolecules. As a consequence of excluded volume effects, compact folded states of proteins should be indirectly stabilized due to destabilization of extended unfolded conformations. Here, we assess the role of excluded volume in terms ...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2012.12.020
更新日期：2013-02-05 00:00:00
abstract：:The power spectrum of current fluctuations and the complex admittance of squid axon were determined in the frequency range 12.5 to 5,000 Hx during membrane voltage clamps to the same potentials in the same axon during internal perfusion with cesium. The complex admittance was determined rapidly and with high resolutio...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(83)84353-7
更新日期：1983-09-01 00:00:00
abstract：:We describe simulations of absorption difference spectra in strongly coupled photosynthetic antennas. In the presence of large resonance couplings, distinctive features arise from excited-state absorption transitions between one- and two-exciton levels. We first outline the theory for the heterodimer and for the gener...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(97)78644-2
更新日期：1997-01-01 00:00:00
abstract：:Mixtures of unsaturated lipids, sphingolipids, and cholesterol form coexisting liquid-disordered and sphingolipid and cholesterol-rich liquid-ordered (Lo) phases in water. The detergent Triton X-100 does not readily solubilize Lo domains, but does solubilize liquid-disordered domains, and is commonly used to prepare d...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/j.bpj.2011.08.059
更新日期：2011-11-16 00:00:00
abstract：:A simulation of the function of the human heart and heart muscle has been developed in the form of a digital computer code. For a given set of values for the input variables, realistic values of the cardiac output variables are predicted. A detailed discussion of the simulation and some results obtained from its appli...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1016/S0006-3495(73)86011-4
更新日期：1973-07-01 00:00:00
abstract：:The genetic information in DNA is transcribed to mRNA and then translated to proteins, which form the building blocks of life. Translation, or protein synthesis, is hence a central cellular process. We have developed a gene-sequence-specific mechanistic model for the translation machinery, which accounts for all the e...
journal_title：Biophysical journal
pub_type： 杂志文章
doi：10.1529/biophysj.106.087825
更新日期：2007-02-01 00:00:00
