Abstract:
:We have applied two-dimensional infrared (2D IR) and betanu correlation spectroscopy to in-situ IR spectroscopy of pulmonary surfactant proteins SP-B and SP-C in lipid-protein monolayers at the air-water interface. For both SP-B and SP-C, a statistical windowed autocorrelation method identified two separate surface pressure regions that contained maximum amide I intensity changes: 4-25 mN/m and 25-40 mN/m. For SP-C, 2D IR and betanu correlation analyses of these regions indicated that SP-C adopts a variety of secondary structure conformations, including alpha-helix, beta-sheet, and an intermolecular aggregation of extended beta-sheet structure. The main alpha-helix band split into two peaks at high surface pressures, indicative of two different helix conformations. At low surface pressures, all conformations of the SP-C molecule reacted identically to increasing surface pressure and reoriented in phase with each other. Above 25 mN/m, however, the increasing surface pressure selectively affected the coexisting protein conformations, leading to an independent reorientation of the protein conformations. The asynchronous 2D IR spectrum of SP-B showed the presence of two alpha-helix components, consistent with two separate populations of alpha-helix in SP-B-a hydrophobic fraction associated with the lipid chains and a hydrophilic fraction parallel to the membrane surface. The distribution of correlation intensity between the two alpha-helix cross peaks indicated that the more hydrophobic helix fraction predominates at low surface pressures whereas the more hydrophilic helix fraction predominates at high surface pressures. The different SP-B secondary structures reacted identically to increasing surface pressure, leading to a reorientation of all SP-B subunits in phase with one another.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Shanmukh S,Howell P,Baatz JE,Dluhy RAdoi
10.1016/s0006-3495(02)73973-8subject
Has Abstractpub_date
2002-10-01 00:00:00pages
2126-41issue
4eissn
0006-3495issn
1542-0086pii
S0006-3495(02)73973-8journal_volume
83pub_type
杂志文章abstract::Crystallographic studies of insulin-protamine complexes, such as neutral protamine Hagedorn (NPH) insulin, have been hampered by high crystal solvent content, small crystal dimensions, and extensive disorder in the protamine molecules. We report herein in situ tapping mode atomic force microscopy (TMAFM) studies of cr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76609-4
更新日期:2000-01-01 00:00:00
abstract::The energy transfer processes between carotenoids and Chls have been studied by femtosecond transient absorption in the CP29-WT complex, which contains only two carotenoids per polypeptide located in the L1 and L2 sites, and in the CP29-E166V mutant in which only the L1 site is occupied. The comparison of these two sa...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)75057-7
更新日期:2003-04-01 00:00:00
abstract::We have examined the kinetics and thermodynamics of the exchange of a fluorescent amphiphile derived from a phospholipid, NBD-DMPE, between serum albumin and the serum lipoproteins of high density (HDL2 and HDL3), LDL, and VLDL. Binding of the fluorescent lipid amphiphile to bovine serum albumin is characterized, at 3...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.047050
更新日期:2005-01-01 00:00:00
abstract::TOK1 encodes the channel responsible for the prominent outward K(+) current of the yeast plasma membrane. It can dwell in several impermeable states, including a rapidly transiting, K(+)-electromotive-force-dependent "R" (rectifying) state, a voltage-independent "IB" (interburst) state, and a set of [K(+)](ext) and vo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75440-4
更新日期:2002-02-01 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::We present a molecular system where polymerization is controlled externally by tuning the elastic energy of the monomers. The elastic energy, provided by a DNA molecular spring, destabilizes the monomer state through a process analogous to domain swapping. This energy can be large (of approximately 10 kT) and thus dri...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.11.065
更新日期:2009-03-18 00:00:00
abstract::The canonical mechanism of gramicidin (gA) channel formation is transmembrane dimerization of nonconducting subunits that reside in opposite bilayer leaflets. The channels do not open and close; they appear and disappear due to subunit association and dissociation. Many different types of experiments support this mono...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.08.049
更新日期:2017-10-17 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::Fluorescence detection, either involving propagating or near-field emission, is widely being used in spectroscopy, sensing, and microscopy. Total internal reflection fluorescence (TIRF) confines fluorescence excitation by an evanescent (near) field, and it is a popular contrast generator for surface-selective fluoresc...
journal_title:Biophysical journal
pub_type: 杂志文章,评审
doi:10.1016/j.bpj.2020.03.029
更新日期:2020-05-19 00:00:00
abstract::Light-induced dielectrophoretic movement of polystyrene beads and lambda-DNA is studied using thin films of amorphous hydrogenated silicon as local photoaddressable electrodes with a diameter of 4 microm. Positive (high-field seeking) dielectrophoretic movement is observed for both types of objects. The absence of str...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.101188
更新日期:2007-08-01 00:00:00
abstract::Inactivation is a fundamental property of voltage-gated ion channels. Fast inactivation of Na(+) channels involves channel block by the III-IV cytoplasmic interdomain linker. The mechanisms of nonfast types of inactivation (intermediate, slow, and ultraslow) are unclear, although the ionic environment and P-loops rear...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.100248
更新日期:2007-09-01 00:00:00
abstract::Multiple molecular dynamics simulations of bacterioopsin pulling from its C-terminus show that its alpha-helices unfold individually. In the first metastable state observed in the simulations, helix G is unfolded at its C-terminal segment while the rest of helix G (residues 200-216) is folded and opposes resistance be...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.106.088591
更新日期:2006-11-01 00:00:00
abstract::Early afterdepolarizations (EADs) are voltage oscillations that occur during the repolarizing phase of the cardiac action potential and cause cardiac arrhythmias in a variety of clinical settings. EADs occur in the setting of reduced repolarization reserve and increased inward-over-outward currents, which intuitively ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.05.011
更新日期:2012-06-20 00:00:00
abstract::Pavlovian conditioning of the nudibranch mollusc Hermissenda crassicornis was previously shown to produce long-lasting reduction of two K+ currents measured across the Type B photoreceptor soma membrane (Alkon et al., 1982a; Alkon et al., 1985). Pavlovian conditioning of the rabbit was also shown to be followed by per...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(88)83031-5
更新日期:1988-11-01 00:00:00
abstract::Glucose-embedded bacteriorhodopsin shows M-intermediates with different Amide I infrared bands when samples are illuminated at 240 or 260 K, in contrast with fully hydrated samples where a single M-intermediate is formed at all temperatures. In hydrated, but not in glucose-embedded specimens, the N intermediate is for...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(94)80585-5
更新日期:1994-09-01 00:00:00
abstract::In this paper we explore the properties of a mathematical model for the passive sodium permeability system of excitable membranes. This model is distinguished by the explicit inclusion of a rate constant which depends not on instantaneous voltage, but on rate of voltage change. Actually, the model is a rather modest m...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(75)85840-1
更新日期:1975-06-01 00:00:00
abstract::The theory of the electromagnetic blood flow measuring technique is extended from the well known case (conductive liquid flowing through an insulating tube) to more realistic situations. First the conductivity of the vessel is taken into account, and the electric potentials in both liquid and vessel wall are calculate...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(61)86912-9
更新日期:1961-11-01 00:00:00
abstract::Profiles of negatively stained gap junctions have been measured by grid sectioning. After normal levels of electron irradiation, the membrane thickness shrinks to about half that of unirradiated controls, but no shrinkage occurs in the hexagonal lattice plane. Even under low irradiation conditions, there is significan...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(88)83152-7
更新日期:1988-05-01 00:00:00
abstract::High-resolution measurement of membrane capacitance in the whole-cell-recording configuration can be used to detect small changes in membrane surface area that accompany exocytosis and endocytosis. We have investigated the noise of membrane capacitance measurements to determine the fundamental limits of resolution in ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76464-2
更新日期:2000-10-01 00:00:00
abstract::The photophysics of the complex forming reaction of Ca2+ and Fura-2 are investigated using steady-state and time-resolved fluorescence measurements. The fluorescence decay traces were analyzed with global compartmental analysis yielding the following values for the rate constants at room temperature in aqueous solutio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80285-7
更新日期:1995-03-01 00:00:00
abstract::Fluorescence correlation microscopy (FCM), the combination of fluorescence correlation spectroscopy (FCS) and digital microscopy (Brock and Jovin, 1998. Cell. Mol. Biol. 44:847-856), has been implemented for measuring molecular diffusion and association in living cells with explicit consideration of autocorrelations a...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77699-4
更新日期:1998-11-01 00:00:00
abstract::Stochastic effects in gene expression may result in different physiological states of individual cells, with consequences for pathogen survival and artificial gene network design. We studied the contributions of a regulatory factor to gene expression noise in four basic mechanisms of negative gene expression control: ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2008.09.052
更新日期:2009-01-01 00:00:00
abstract::We present a theoretical model for aqueous solutions of double-stranded (ds) DNA with explicit consideration of electrostatic interactions, excluded-volume effects, van der Waals attractions, and salt ions. With reasonable parameters estimated from the DNA structure and experimental data for electrolytes, we are able ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.112508
更新日期:2008-02-01 00:00:00
abstract::Here, we present a structural and dynamic description of CBP-ID4 at atomic resolution. ID4 is the fourth intrinsically disordered linker of CREB-binding protein (CBP). In spite of the largely disordered nature of CBP-ID4, NMR chemical shifts and relaxation measurements show a significant degree of α-helix sampling in ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.11.3516
更新日期:2016-01-19 00:00:00
abstract::The present article considers the influence of heterogeneity in a mobile analyte or in an immobilized ligand population on the surface binding kinetics and equilibrium isotherms. We describe strategies for solving the inverse problem of calculating two-dimensional distributions of rate and affinity constants from expe...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)75132-7
更新日期:2003-06-01 00:00:00
abstract::Herein, we identify the coordination environment of Cu²(+) in the human α1-glycine receptor (GlyR). GlyRs are members of the pentameric ligand-gated ion channel superfamily (pLGIC) that mediate fast signaling at synapses. Metal ions like Zn²(+) and Cu²(+) significantly modulate the activity of pLGICs, and metal ion co...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.08.050
更新日期:2010-10-20 00:00:00
abstract::The E5 oncoprotein is the major transforming protein of bovine papillomavirus type 1. This 44-residue transmembrane protein can interact with the platelet-derived growth factor receptor β, leading to ligand-independent activation and cell transformation. For productive interaction, E5 needs to dimerize via a C-termina...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.06.073
更新日期:2010-09-22 00:00:00
abstract::Molecular dynamics simulations of protein folding and unfolding are often carried out at temperatures (400-600 K) that are much higher than physiological or room temperature to speed up the (un)folding process. Use of such high temperatures changes both the protein and solvent properties considerably, compared to phys...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(00)76820-2
更新日期:2000-06-01 00:00:00
abstract::Neutron diffraction from oriented multibilayers has been used to study the bilayer interaction of the amphipathic peptide salmon calcitonin. Penetration of calcitonin into bilayers composed of dioleoylphosphatidylcholine increases with the addition of 15% (mol) of the anionic phospholipid dioleoylphosphatidylglycerol....
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(97)78861-1
更新日期:1997-05-01 00:00:00
abstract::Electrorotation of fixed red blood cells has been investigated in the frequency range between 16 Hz and 30 MHz. The rotation was studied as a function of electrolyte conductivity and surface charge density. Between 16 Hz and 1 kHz, fixed red blood cells undergo cofield rotation. The maximum of cofield rotation occurs ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77918-4
更新日期:1998-04-01 00:00:00