Abstract：
:The effect of temperature on the velocity of rhodamine phalloidin-labelled F-actin moving in vitro on rabbit skeletal myosin has been studied. Translating actin filaments were visualized by epi-fluorescence in an inverted microscope, equipped with temperature control (+/- 0.2 K) of the stage and objective. Images were recorded in real time at magnifications of 400x or 160x by an intensified CCD camera on video tape. Motion of individual filaments was tracked by hand and velocities determined using frame times recorded simultaneously on the video tape. Velocity changed from 12 microns per second at 42 degrees C to 11 nm per second at 3 degrees C. The Arrhenius plot is non-linear, with the data following a cubic regression curve with no evident breaks or jumps. Data taken over the temperature range from single preparations followed the same curve for both heating and cooling; this indicates reversibility and absence of hysteresis. A hyperbolic model that smoothly translates with temperature between two asymptotic activation energies fits the data above 7 degrees C: these energies are 50(+/- 5) kJ per mole (Q10 = 1.9) at high temperatures and 289(+/- 29) kJ per mole (Q10 = 76.5) at low temperature with a transition temperature of 15.4(+/- 0.6) degrees C. These values are compared with other measurements made in vitro, in solution studies and on muscle fibres. An Arrhenius activation energy of 50 kJ per mole and a transition temperature of 15 degrees C are consistent with previous determinations but 289 kJ per mole is significantly greater than has been seen at low temperatures in other systems. This may indicate a different rate-limiting step in the kinetics of skeletal myosin driving actin filaments in vitro below 15 degrees C. Current determinations of the myosin "step-size" assume that the actin velocity is determined by the rate of ATP hydrolysis; the data confirm similar activation energies above 20 degrees C but they show that the temperature dependencies and activation energies are different at lower temperatures, implying uncoupling of the two processes.
journal_name
J Mol Bioljournal_title
Journal of molecular biologyauthors
Anson Mdoi
10.1016/0022-2836(92)90467-xkeywords:
subject
Has Abstractpub_date
1992-04-20 00:00:00pages
1029-38issue
4eissn
0022-2836issn
1089-8638pii
0022-2836(92)90467-Xjournal_volume
224pub_type
杂志文章abstract：:Molecular aspects of thermal adaptation of proteins were studied by following the co-evolution of temperature dependence, conformational stability, and substrate specificity in a cold-active lipase modified via directed evolution. We found that the evolution of kinetic stability was accompanied by a relaxation in subs...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2009.10.026
更新日期：2010-01-08 00:00:00
abstract：:The major anaerobically induced outer membrane protein (AniA) from pathogenic Neisseria gonorrhoeae is essential for cell growth under oxygen limiting conditions in the presence of nitrite and is protective against killing by human sera. A phylogenic analysis indicates that AniA is a member of a new class of copper-co...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.2001.5251
更新日期：2002-02-01 00:00:00
abstract：:A 26 Å resolution map of the structure of human low-density lipoprotein (LDL) was obtained from electron cryomicroscopy and single-particle image reconstruction. The structure showed a discoidal-shaped LDL particle with high-density regions mainly distributed at the edge of the particle and low-density regions at the ...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2010.10.034
更新日期：2011-01-07 00:00:00
abstract：:Here, we report a new computational method, called sheetminer, for mining beta-sheets in the density maps at intermediate resolutions of 6 to 10A. The method employs a multi-step ad hoc morphological analysis of density maps to identify the unique characteristics of beta-sheets. It was tested on density maps from 12 p...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/s0022-2836(03)00859-3
更新日期：2003-09-12 00:00:00
abstract：:Mutants of an archaeon Halobacterium halobium, resistant to the universal inhibitor of translation, pactamycin, were isolated. Pactamycin resistance correlated with the presence of mutations in the 16 S rRNA gene of H. halobium single rRNA operon. Three types of mutations were found in pactamycin resistant cells, A694...
journal_title：Journal of molecular biology
pub_type： 杂志文章,评审
doi：10.1006/jmbi.1997.1387
更新日期：1997-11-21 00:00:00
abstract：:Ebolaviruses are causative agents of lethal hemorrhagic fever in humans and nonhuman primates. Among the filoviruses characterized thus far, Reston Ebola virus (REBOV) is the only Ebola virus that is nonpathogenic to humans despite the fact that REBOV can cause lethal disease in nonhuman primates. Previous studies als...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2010.04.022
更新日期：2010-06-11 00:00:00
abstract：:Actin and myosin are the two main proteins required for cell motility and muscle contraction. The structure of their strongly bound complex-rigor state-is a key for delineating the functional mechanism of actomyosin motor. Current knowledge of that complex is based on models obtained from the docking of known atomic s...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2011.09.035
更新日期：2011-11-25 00:00:00
abstract：:Structures of glycoconjugate N-glycans and glycolipids of invertebrates show significant differences from those of vertebrates. These differences are due largely to the vertebrate beta1,4-galactosyltransferase-1 (beta4Gal-T1), which is found as a beta1,4-N-acetylgalactosaminyltransferase (beta4GalNAc-T1) in invertebra...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2006.10.034
更新日期：2007-01-19 00:00:00
abstract：:Riboswitches are noncoding RNA elements that are commonly found in the 5'-untranslated region of bacterial mRNA. Binding of a small-molecule metabolite to the riboswitch aptamer domain guides the folding of the downstream sequence into one of two mutually exclusive secondary structures that directs gene expression. Th...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2008.10.074
更新日期：2009-01-23 00:00:00
abstract：:HtrA (high-temperature requirement A) family proteins play important roles in protein-quality control processes in the bacterial periplasm. A common feature of all members of this family is their modular organization comprising a chymotrypsin-like protease domain and at least one PDZ (postsynaptic density of 95 kDa, d...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2015.06.023
更新日期：2015-08-28 00:00:00
abstract：:The anticancer drug daunomycin has been co-crystallized with the hexanucleotide duplex sequences d(TGTACA) and d(TGATCA) and single crystal X-ray diffraction studies of these two complexes have been carried out. Structure solution of the d(TGTACA) and d(TGATCA) complexes to 1.6 and 1.7 Angstrom resolution, respectivel...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(91)90203-i
更新日期：1991-11-20 00:00:00
abstract：:TrmD and Trm5 are, respectively, the bacterial and eukarya/archaea methyl transferases that catalyze transfer of the methyl group from S-adenosyl methionine (AdoMet) to the N1 position of G37 in tRNA to synthesize m1G37-tRNA. The m1G37 modification prevents tRNA frameshifts on the ribosome by assuring correct codon-an...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2007.08.010
更新日期：2007-10-26 00:00:00
abstract：:Collagens contain sequence- and conformation-dependent epitopes responsible for their digestion by collagenases at specific loci. A synthetic heterotrimer construct containing the collagenase cleavage site of collagen type I was found to mimic perfectly native collagen in terms of selectivity and mode of enzymatic deg...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/S0022-2836(02)00365-0
更新日期：2002-06-21 00:00:00
abstract：:Sirtuins are NAD+-dependent protein deacetylase enzymes that are broadly conserved from bacteria to human, and have been implicated to play important roles in gene regulation, metabolism and longevity. cobB is a bacterial sirtuin that deacetylates acetyl-CoA synthetase (Acs) at an active site lysine to stimulate its e...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2004.01.060
更新日期：2004-03-26 00:00:00
abstract：:Neutron-scattering in combination with quasi-elastic light-scattering and electron microscopy was used to derive a model for the capsid structure of the Top a-t component of alfalfa mosaic virus (AMV-Ta-t). In the electron microscope, AMV-Ta-t appears as an irregular ellipsoidal particle with apparent dimensions 275 (...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/s0022-2836(83)80350-7
更新日期：1983-12-05 00:00:00
abstract：:The Escherichia coli trigger factor is a peptidyl-prolyl cis/trans isomerase (PPIase) which catalyzes proline-limited protein folding extremely well. It has been found associated with nascent protein chains as well as with the chaperone GroEL. The trigger factor utilizes protein regions outside the central catalytic d...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1997.1206
更新日期：1997-09-05 00:00:00
abstract：:Polycystin-1 is a large membrane-associated protein that interacts with polycystin-2 in the primary cilia of renal epithelial cells to form a mechanosensitive ion channel. Bending of the cilia induces calcium flow into the cells, mediated by the polycystin complex. Antibodies to polycystin-1 and polycystin-2 abolish t...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2005.04.008
更新日期：2005-06-17 00:00:00
abstract：:The Escherichia coli wild-type single strand binding (SSB) protein is a stable tetramer that binds to single-stranded (ss) DNA in its role in DNA replication, recombination and repair. The ssb-1 mutation, a substitution of tyrosine for histidine-55 within the SSB-1 protein, destabilizes the tetramer with respect to mo...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(91)90611-9
更新日期：1991-01-05 00:00:00
abstract：:The structures of transition states and intermediates in protein folding may be analysed by protein engineering methods that remove simple interactions that stabilize the folded state. We have now extended the range and reliability of the procedure by using the COSMIC (Combination of Sequential Mutant Interaction Cycl...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(91)90852-w
更新日期：1991-05-05 00:00:00
abstract：:The stability of the structure of sperm whale metmyoglobin has been studied in various solutions, in the temperature range -8 degrees C to 100 degrees C, by scanning microcalorimetry, light absorption, circular dichroism, nuclear magnetic resonance spectroscopy and viscosimetry. It has been shown that in 10 mM-sodium ...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(86)90017-3
更新日期：1986-08-05 00:00:00
abstract：:Expansion of the polyglutamine (polyQ) region in the protein ataxin-3 is associated with spinocerebellar ataxia type 3, an inherited neurodegenerative disorder that belongs to the family of polyQ diseases. Increasing evidence indicates that protein aggregation and fibre formation play an important role in these pathol...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2004.09.065
更新日期：2004-12-03 00:00:00
abstract：:Drosophila development is regulated by two hormones, 20-hydroxyecdysone (ecdysone) and juvenile hormone. We previously found that expression of the E75 gene is induced by both hormones in cultured S2 cells. E75 occupies over 100 kb of genomic DNA; it has four alternative promoters producing isoforms E75A, E75B, E75C, ...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2009.02.013
更新日期：2009-04-10 00:00:00
abstract：:The structure of replicating simian virus 40 (SV40) minichromosomes was studied by DNA crosslinking with trimethyl-psoralen. The procedure was used both in vitro with extracted SV40 minichromosomes as well as in vivo with SV40-infected cells. Both procedures gave essentially the same results. Mature SV40 minichromosom...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(86)90390-6
更新日期：1986-05-05 00:00:00
abstract：:Cobalamin-independent methionine synthase (MetE) catalyzes the direct transfer of a methyl group from methyltetrahydrofolate to l-homocysteine to form methionine. Previous studies have shown that the MetE active site coordinates a zinc atom, which is thought to act as a Lewis acid and plays a role in the activation of...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2011.08.005
更新日期：2011-09-30 00:00:00
abstract：:The secondary structure of bacterial RNase P RNA, a ribozyme responsible for the maturation of the 5' end of tRNAs, is well established on the basis of sequence comparison analysis. RNase P RNA secondary structures fall into two types, A and B, which share a common core formed by the assembly of two main folding domai...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1998.1797
更新日期：1998-06-19 00:00:00
abstract：:Ionotropic glutamate receptors (iGluRs) mediate excitatory neurotransmission in the central nervous system and play key roles in brain development and disease. iGluRs have two distinct extracellular domains, but the functional role of the distal N-terminal domain (NTD) is poorly understood. Crystal structures of the N...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2011.09.037
更新日期：2011-11-18 00:00:00
abstract：:We have analysed nucleotide sequences at the junction between simian virus 40 (SV40) and cellular DNA in the Fisher rat transformed line tsA30-N2. This line contains a single insertion of one complete SV40 genome with a terminal duplication of 267 nucleotides, the recombination sites being located at nucleotides 439 a...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/0022-2836(84)90057-3
更新日期：1984-07-25 00:00:00
abstract：:The torsion constants of both circular and linear forms of the same 181 bp DNA were investigated by time-resolved fluorescence polarization anisotropy (FPA) of intercalated ethidium. The ratio of intrinsic ethidium binding constants of the circular and linear species was determined from the relative fluorescence inten...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1006/jmbi.1996.0432
更新日期：1996-08-02 00:00:00
abstract：:Controlled activity of several kinesin motors is required for the proper assembly of the mitotic spindle. Eg5, a homotetrameric bipolar kinesin-5 from Xenopus laevis, can cross-link and slide anti-parallel microtubules apart by a motility mechanism comprising diffusional and directional modes. How this mechanism is re...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2010.03.009
更新日期：2010-05-28 00:00:00
abstract：:Under usual laboratory conditions, lysis by bacteriophage lambda requires only the holin and endolysin genes, but not the Rz and Rz1 genes, of the lysis cassette. Defects in Rz or Rz1 block lysis only in the presence of high concentrations of divalent cations. The lambda Rz and Rz1 lysis genes are remarkable in that R...
journal_title：Journal of molecular biology
pub_type： 杂志文章
doi：10.1016/j.jmb.2007.08.045
更新日期：2007-11-09 00:00:00
