Abstract:
:The effects of different cations on the hydrodynamic radius (RH) of a 48-bp synthetic DNA are measured by time-resolved fluorescence polarization anisotropy of intercalated ethidium. Relative statistical errors in RH are only approximately 1%. With increasing cation concentration, Na+ causes a small decrease in RH, Cs+ causes a somewhat larger decrease by up to 0.5 A at 100 mM, and (CH3CH2)4N+ causes an increase in RH by approximately 0.5 A at 100 mM. The qualitatively different effects of these monovalent cations indicates that the changes in RH with cation concentration do not arise primarily from electrolyte friction. Divalent cations cause much larger increases in RH with increasing cation concentration. Mg2+ causes an increase in RH by up to 1.0 A at 24.4 mM, and Mn2+ causes an increase in RH by up to 1.6 A at 24.4 mM. These effects are independent of DNA concentration. There is some positive correlation between the order of effects of the different cations on RH and the order of their effects on interhelical hydration forces. It is suggested that these different ions affect RH either by altering the hydration layer or possibly by some effect on DNA structure, such as stabilizing bends.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Fujimoto BS,Miller JM,Ribeiro NS,Schurr JMdoi
10.1016/S0006-3495(94)80481-3subject
Has Abstractpub_date
1994-07-01 00:00:00pages
304-8issue
1eissn
0006-3495issn
1542-0086pii
S0006-3495(94)80481-3journal_volume
67pub_type
杂志文章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
abstract::We measure the organization and substructure of HT29 epithelial cells in a monolayer using angle-resolved low-coherence interferometry. This new technique probes cellular structure by measuring scattered light, as in flow cytometry, but offers an advantage in that the structure can be examined in situ, avoiding the ne...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75571-9
更新日期:2002-04-01 00:00:00
abstract::During postnatal development, major changes in mechanical properties of skeletal muscle occur. We investigated passive properties of skeletal muscle in mice and rabbits that varied in age from 1 day to approximately 1 year. Neonatal skeletal muscle expressed large titin isoforms directly after birth, followed by a gra...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.07.041
更新日期:2009-10-21 00:00:00
abstract::Far infrared (FIR) spectral measurements of wild-type (WT) and D96N mutant bacteriorhodopsin thin films have been carried out using terahertz time domain spectroscopy as a function of hydration, temperature, and conformational state. The results are compared to calculated spectra generated via normal mode analyses usi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74562-7
更新日期:2003-08-01 00:00:00
abstract::The time-resolved thermodynamics of the flavin mononucleotide (FMN)-binding LOV1 domain of Chlamydomonas reinhardtii phot (phototropin homolog) was studied by means of laser-induced optoacoustic spectroscopy. In the wild-type protein the early red-shifted intermediate LOV(715) exhibits a small volume contraction, Delt...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(04)74180-6
更新日期:2004-02-01 00:00:00
abstract::Guanine-rich DNA repeat sequences located at the terminal ends of chromosomal DNA can fold in a sequence-dependent manner into G-quadruplex structures, notably the terminal 150-200 nucleotides at the 3' end, which occur as a single-stranded DNA overhang. The crystal structures of quadruplexes with two and four human t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.120501
更新日期:2008-07-01 00:00:00
abstract::The stability of the 1:1 complex of sodium ion with the dianion of guanosine 5'-monophosphate has been determined by means of a potentiometric titration employing a specific ion electrode. The stability constant for the reaction Na(+) + 5'-GMP(2-) Na(5'-GMP)(-) was found to be 2.85 +/- 0.36 M(-1) at 5 degrees C and an...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/s0006-3495(82)84564-5
更新日期:1982-06-01 00:00:00
abstract::Electron paramagnetic resonance spectroscopy was used to monitor the orientation of muscle cross-bridges attached to actin in a low force and high stiffness state that may occur before force generation in the actomyosin cycle of interactions. 2,3-butanedione monoxime (BDM) has been shown to act as an uncompetitive inh...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80375-9
更新日期:1995-05-01 00:00:00
abstract::Evidence from electron microscopy indicates that the separation between adjacent membranes of the central nervous system (CNS) is less than 500 A and perhaps as small as 100-250 A. The rapid K(+) efflux associated with the neural action potential may therefore be sufficient to affect the local extracellular potassium ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(70)86310-X
更新日期:1970-05-01 00:00:00
abstract::Morphogenesis of epithelial tissues requires tight spatiotemporal coordination of cell shape changes. In vivo, many tissue-scale shape changes are driven by pulsatile contractions of intercellular junctions, which are rectified to produce irreversible deformations. The functional role of this pulsatory ratchet and its...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.09.027
更新日期:2019-11-05 00:00:00
abstract::Actin filaments are semiflexible polymers that display large-scale conformational twisting and bending motions. Modulation of filament bending and twisting dynamics has been linked to regulatory actin-binding protein function, filament assembly and fragmentation, and overall cell motility. The relationship between act...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.07.009
更新日期:2010-09-22 00:00:00
abstract::A complete mechanistic understanding of membrane-localized processes in vesicular transport, such as membrane budding and fission, requires their reconstitution with biochemically-defined components from a biochemically-defined substrate. Supported bilayers formed by vesicle fusion represent an attractive substrate fo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.04.036
更新日期:2010-07-21 00:00:00
abstract::Viral infection begins with the binding of a virus to a specific target on the surface of the host cell, followed by viral genome delivery into the host and a continuation of the infection process. Before binding occurs, the virus must first find its receptor by a process whose details are largely unknown. We applied ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.05.014
更新日期:2011-06-22 00:00:00
abstract::Fusion of a vesicle with its target membrane is preceded by tethering or docking. However, the physical mechanism of vesicle-tethering is unknown. To study this mechanism, we used eosinophil secretory granules, which undergo stimulated homotypic fusion events inside the cell during degranulation. Using a dual optical ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.108.132670
更新日期:2008-11-15 00:00:00
abstract::Fitting dwell-time distributions with sums of exponentials is widely used to characterize histograms of open- and closed-interval durations recorded from single ion channels, as well as for other physical phenomena. However, it can be difficult to identify the contributing exponential components. Here we extend previo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2013.04.030
更新日期:2013-06-04 00:00:00
abstract::Immature human immunodeficiency virus (HIV) virions have a lattice of Gag and Gag-Pol proteins anchored to the lumen of their envelope. Using electron microscopy, we demonstrate that HIV virus-like particles (VLPs) assembled by the viral protein Gag and tagged at its C-terminus with the fluorescent protein Dendra2 hav...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2020.06.023
更新日期:2020-08-04 00:00:00
abstract::We have attempted to link the solution actomyosin ATPase with the mechanical properties of in vitro actin filament sliding over heavy meromyosin. To accomplish this we perturbed the system by altering the substrate with various NTPs and divalent cations, and by altering ionic strength. A wide variety of enzymatic and ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)76022-5
更新日期:2001-01-01 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::Current methods for screening cell receptor internalization often require complex image analysis with limited sensitivity. Here we describe a novel bioassay based on detection of changes in global fluorescence lifetime above a gold substrate, with superresolution axial sensitivity and no need for image analysis. We sh...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.03.016
更新日期:2010-06-02 00:00:00
abstract::Calmodulin (CaM) expression is upregulated upon HIV-1 infection and interacts with proteins involved in viral processing, including the multifunctional HIV-1 MA protein. We present here the results of studies utilizing small-angle neutron scattering with contrast variation that, when considered in the light of earlier...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2012.06.042
更新日期:2012-08-08 00:00:00
abstract::A phenomenological theory for contracting muscle based on irreversible thermodynamics and the sliding filament theory is developed. The individual cross bridges, considered as subunits, are viewed as linear energy converters with constant transport coefficients. With this view of the subunits, phenomenological equatio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(70)86290-7
更新日期:1970-02-01 00:00:00
abstract::The skeletal muscles of chickens, frogs, and fish have been reported to express two isoforms (alpha and beta) of the sarcoplasmic reticulum calcium release channel (ryanodine receptor or RYR), while mammals express only one. We have studied patterns of RYR isoform expression in skeletal muscles from a variety of fish,...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81303-1
更新日期:1993-12-01 00:00:00
abstract::The interaction between two stiff parallel DNA molecules is discussed using linear Debye-Hückel screening theory with and without inclusion of the dielectric discontinuity at the DNA surface, taking into account the helical symmetry of DNA. The pair potential furthermore includes the amount and distribution of counter...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)75092-9
更新日期:2003-06-01 00:00:00
abstract::Protein-mediated DNA looping, such as that induced by the lactose repressor (LacI) of Escherichia coli, is a well-known gene regulation mechanism. Although researchers have given considerable attention to DNA looping by LacI, many unanswered questions about this mechanism, including the role of protein flexibility, re...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.06.040
更新日期:2011-08-03 00:00:00
abstract::We investigated whether transient step reductions in divalent cations would produce detectable changes in neuronal excitability similar to those reported in the total absence of divalent cations. Using cultured chick dorsal root ganglion cells as a model system, our results indicate that a step reduction in divalent c...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(86)83515-9
更新日期:1986-10-01 00:00:00
abstract::A requirement for concentrated and chemically homogeneous pools of molecular building blocks would severely restrict plausible scenarios for the origin of life. In the case of membrane self-assembly, models of prebiotic lipid synthesis yield primarily short, single-chain amphiphiles that can form bilayer vesicles only...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.07.067
更新日期:2014-10-07 00:00:00
abstract::By exploring a recent model in which DNA bending elasticity, described by the wormlike chain model, is coupled to basepair denaturation, we demonstrate that small denaturation bubbles lead to anomalies in the flexibility of DNA at the nanometric scale, when confined in two dimensions (2D), as reported in atomic-force ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.03.035
更新日期:2009-06-03 00:00:00
abstract::The interactions between phospholipid molecules in suspensions have been studied by using mass spectrometry. Electrospray mass spectra of homogeneous preparations formed from three different phospholipid molecules demonstrate that under certain conditions interactions between 90 and 100 lipid molecules can be preserve...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74795-X
更新日期:2003-12-01 00:00:00
abstract::Specific amino acid sequence segments have been assigned to locations in the structural map of bacteriorhodopsin using two-dimensional neutron diffraction data and a model building analysis. Models are constructed computationally by building specific regions of the amino acid sequence as alpha helices and then positio...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(83)84391-4
更新日期:1983-06-01 00:00:00
abstract::Closing linear poly(ethylene glycol) (PEG) into a circular "crown" dramatically changes its dynamics in the alpha-hemolysin channel. In the electrically neutral crown ether (C2H4O)6, six ethylene oxide monomers are linked into a circle that gives the molecule ion-complexing capacity and increases its rigidity. As with...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.044453
更新日期:2004-11-01 00:00:00