Abstract:
:A useful technique in studying the saturation of hemoglobin in erythrocytes or myoglobin in tissue is cryophotometry, in which tissue is frozen for later spectrophotometric analysis. A general question associated with this technique is whether the freezing process alters the chemical state. This paper presents a theoretical analysis of the simplest model relevant to that question. We study the effect of rapid cooling on a spatially homogeneous chemical reaction. The analysis shows that changes during freezing are negligible near the boundary to which the heat sink is applied, but can be significant deeper in the sample. The distance from the boundary at which the changes during freezing become appreciable can be expressed simply in terms of the chemical reaction rates and the thermal diffusivity of the tissue. Detailed results are given for the case of oxygen and myoglobin in skeletal muscle.
journal_name
Biophys Jjournal_title
Biophysical journalauthors
Clark A Jr,Clark PAdoi
10.1016/S0006-3495(83)84365-3subject
Has Abstractpub_date
1983-04-01 00:00:00pages
25-30issue
1eissn
0006-3495issn
1542-0086pii
S0006-3495(83)84365-3journal_volume
42pub_type
杂志文章abstract::The folding pathway of the small α/β protein GB1 has been extensively studied during the past two decades using both theoretical and experimental approaches. These studies provided a consensus view that the protein folds in a two-state manner. Here, we reassessed the folding of GB1, both by experiments and simulations...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2011.09.013
更新日期:2011-10-19 00:00:00
abstract::The redox-driven proton pump cytochrome c oxidase is that enzymatic machinery of the respiratory chain that transfers electrons from cytochrome c to molecular oxygen and thereby splits molecular oxygen to form water. To investigate the reaction mechanism of cytochrome c oxidase on the single vibrational level, we used...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75368-X
更新日期:2002-01-01 00:00:00
abstract::The current rapid expansion of biological knowledge offers a great opportunity to rationally engineer biological systems that respond to signals such as light and chemical inducers by producing specific proteins. Turning on and off the production of proteins on demand holds great promise for creating significant biote...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.105.064204
更新日期:2005-12-01 00:00:00
abstract::Diffraction rings corresponding to the first, second, and third order were obtained by laser light illumination from a suspension of rabbit glycerinated psoas myofibrils (diameter, 1-2 microns; average length of the straight region, 44 microns; average sarcomere length, 2.2-2.6 microns) of which the optical thickness ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(89)82759-6
更新日期:1989-12-01 00:00:00
abstract::The pKa values of ionizable groups that lie between the active site region of bacteriorhodopsin (bR) and the extracellular surface of the protein are reported. Glu-204 is found to have an elevated pKa in the resting state of bR, suggesting that it corresponds to the proton-releasing group in bR. Its elevated pKa is pr...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(96)79320-7
更新日期:1996-09-01 00:00:00
abstract::Thermodynamic analysis of metabolic networks has recently generated increasing interest for its ability to add constraints on metabolic network operation, and to combine metabolic fluxes and metabolite measurements in a mechanistic manner. Concepts for the calculation of the change in Gibbs energy of biochemical react...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2010.09.043
更新日期:2010-11-17 00:00:00
abstract::Experimentally, short peptides have been shown to form amyloids similar to those of their parent proteins. Consequently, they present useful systems for studies of amyloid conformation. Here we simulate extensively the NFGAIL peptide, derived from the human islet amyloid polypeptide (residues 22-27). We simulate diffe...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(03)74996-0
更新日期:2003-03-01 00:00:00
abstract::The oligomeric state and function of band 3, purified by sulfhydryl affinity chromatography in reduced Triton X-100, was investigated. Size exclusion high-performance liquid chromatography showed that a homogeneous population of band 3 dimers could be purified from whole erythrocyte membranes. The elution profile of b...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(99)77361-3
更新日期:1999-04-01 00:00:00
abstract::Fluorescence resonance energy transfer (FRET) was used to reveal aspects of the mechanism of signal transduction by epidermal growth factor receptors (EGFR). The superpositions of epidermal growth factor (EGF), transforming growth factor-alpha (TGFalpha) and an antibody fragment (29.1) to the carbohydrate extremity of...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(02)75585-9
更新日期:2002-05-01 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 geometry of domains in phospholipid bilayers of binary (1:1) mixtures of synthetic lecithins with a difference in chain length of four methylene groups has been studied by two independent, direct and complementary methods. Grazing incidence diffraction of neutrons provided gel domain sizes of less than 10 nm in bo...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(98)77952-4
更新日期:1998-05-01 00:00:00
abstract::The structure of a membrane-embedded alpha-helical reference protein, the M13 major coat protein, is characterized under different conditions of hydrophobic mismatch using fluorescence resonance energy transfer in combination with high-throughput mutagenesis. We show that the structure is similar in both thin (14:1) a...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.112698
更新日期:2007-11-15 00:00:00
abstract::Although both RNA and proteins have densely packed native structures, chain organizations of these two biopolymers are fundamentally different. Motivated by the recent discoveries in chromatin folding that interphase chromosomes have territorial organization with signatures pointing to metastability, we analyzed the b...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2016.04.020
更新日期:2016-06-07 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::Melittin has been reported to form toroidal pores under certain conditions, but the atomic-resolution structure of these pores is unknown. A 9-μs all-atom molecular-dynamics simulation starting from a closely packed transmembrane melittin tetramer in DMPC shows formation of a toroidal pore after 1 μs. The pore remains...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.04.006
更新日期:2015-05-19 00:00:00
abstract::The fluorescent Mg(2+) indicator furaptra (mag-fura-2) was introduced into single ventricular myocytes by incubation with its acetoxy-methyl ester form. The ratio of furaptra's fluorescence intensity at 382 and 350 nm was used to estimate the apparent cytoplasmic [Mg(2+)] ([Mg(2+)](i)). In Ca(2+)-free extracellular co...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.055517
更新日期:2005-03-01 00:00:00
abstract::Multiplex hybridization reactions of perfectly matched duplexes and duplexes containing a single basepair mismatch (SNPs) were investigated on DNA microarrays. Effects of duplex length, G-C percentage, and relative position of the SNP on duplex hybridization and SNP resolution were determined. Our theoretical model of...
journal_title:Biophysical journal
pub_type: 信件
doi:10.1529/biophysj.107.105320
更新日期:2007-05-15 00:00:00
abstract::Supercoiled DNA polymer models for which the torsional energy depends on the total twist of molecules (Tw) are a priori well suited for thermodynamic analysis of long molecules. So far, nevertheless, the exact determination of Tw in these models has been based on a computation of the writhe of the molecules (Wr) by ex...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2015.06.005
更新日期:2015-07-07 00:00:00
abstract::We have considered whether lecithin surface films below the gel-liquid crystal transition temperature, Tc, are in unique physical states. In general, below Tc, equilibrium films do not exist when surface pressures, pi, exceed about 0.1 dyn/cm. Since surface pressure-surface area isotherms of lecithin films below Tc al...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(77)85615-4
更新日期:1977-06-01 00:00:00
abstract::Amyloid diseases are traditionally characterized by the appearance of inter- and intracellular fibrillar protein deposits, termed amyloid. Historically, these deposits have been thought to be the etiology of the disease. However, recent evidence suggests that small oligomers of the amyloidogenic protein/peptide are th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2009.05.035
更新日期:2009-08-05 00:00:00
abstract::An equation of state for lipid monolayers at the air-water interface is presented, which takes into account the effects of the conformation and the number and position of double bonds of the hydrocarbon chains. The total Hamiltonian of the monolayer is assumed to consist of three terms. Two of them are calculated exac...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)79919-2
更新日期:1995-08-01 00:00:00
abstract::The theoretical relationships between the fluorescence and photochemical yields of PS II and the fraction of open reaction centers are examined in a general model endowed with the following features: i) a homogeneous, infinite PS II domain; ii) exciton-radical-pair equilibrium; and iii) different rates of exciton tran...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(95)80429-7
更新日期:1995-06-01 00:00:00
abstract::Actin is ubiquitous globular protein that polymerizes into filaments and forms networks that participate in the force generation of eukaryotic cells. Such forces are used for cell motility, cytokinesis, and tissue remodeling. Among those actin networks, we focus on the actin cortex, a dense branched network beneath th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2014.07.008
更新日期:2014-08-19 00:00:00
abstract::Late-onset heart failure (HF) is a known side effect of doxorubicin chemotherapy. Typically, patients are diagnosed when already at an irreversible stage of HF, which allows few or no treatment options. Identifying the causes of compromised cardiac function in this patient group may improve early patient diagnosis and...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2019.07.033
更新日期:2019-12-17 00:00:00
abstract::It is often assumed that pH(i) is spatially uniform within cells. A double-barreled microperfusion system was used to apply solutions of weak acid (acetic acid, CO(2)) or base (ammonia) to localized regions of an isolated ventricular myocyte (guinea pig). A stable, longitudinal pH(i) gradient (up to 1 pH(i) unit) was ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.104.051391
更新日期:2005-04-01 00:00:00
abstract::Oriented solid-state NMR in combination with multiple-residue-specific (15)N labeling and extensive numerical spectral analysis is proposed to determine helix conformations of large membrane proteins in native membranes. The method is demonstrated on uniaxially oriented samples of (15)N-methionine, -valine, and -glyci...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1529/biophysj.107.116004
更新日期:2008-01-01 00:00:00
abstract::The crystal structure of the Mycobacterium tuberculosis homolog of the bacterial mechanosensitive channel of large conductance (Tb-MscL) provides a unique opportunity to consider mechanosensitive signal transduction at the atomic level. Molecular dynamics simulations of the Tb-MscL channel embedded in an explicit lipi...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(01)75791-8
更新日期:2001-09-01 00:00:00
abstract::Chemotactic effects of dissolved oxygen on motions of Escherichia coli in a motility buffer solution have been studied by measurements of quasielastic light scattering. Under conditions where the bacteria form a sharp band in an oxygen concentrations gradient created by their metabolism, components of motions along th...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(81)84724-8
更新日期:1981-10-01 00:00:00
abstract::N-methyl-d-aspartate (NMDA) receptors are glutamate- and glycine-gated channels that flux Na+ and Ca2+ into postsynaptic neurons during synaptic transmission. The resulting intracellular Ca2+ transient is essential to physiological and pathological processes related to synaptic development, plasticity, and apoptosis. ...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/j.bpj.2017.06.035
更新日期:2017-11-21 00:00:00
abstract::Deuterium and phosphorus nuclear magnetic resonance (NMR) has been used to investigate the dynamics of slow motional processes induced in bilayer cardiolipin upon binding with cytochrome c. 31P NMR line shapes suggest that protein binding induces less restricted, isotropic-like motions in the lipid phosphates within t...
journal_title:Biophysical journal
pub_type: 杂志文章
doi:10.1016/S0006-3495(93)81048-8
更新日期:1993-07-01 00:00:00