Abstract:
:The labeled inorganic phosphate formed by enzymatic hydrolysis of [gamma-18O]ATP in normal water was derivatized to trimethyl phosphate and analyzed for the proportions of [18O3]Pi, [18O2]Pi, [18O1]Pi, and [18O0]Pi. The proportions observed were correlated with the kinetics of intermediate exchange by using a kinetic relationship in which it is assumed that binding of ATP and subsequent release of products are irreversible. Actomyosin and acto-heavy meromyosin catalyze intermediate exchange at a mean rate that is more than 1 order of magnitude slower than that predicted by rapid kinetic studies or implied by the essentially complete intermediate exchange observed with myosin alone. The reason for the slow apparent exchange is that there are two ATPase activities with different exchange properties. The effect of varying heavy meromyosin concentrations at a constant actin concentration shows that the two activities are interrelated and suggests further that one is due to ATP hydrolysis by the undissociated actomyosin crossbridge.
journal_name
Proc Natl Acad Sci U S Aauthors
Midelfort CFdoi
10.1073/pnas.78.4.2067subject
Has Abstractpub_date
1981-04-01 00:00:00pages
2067-71issue
4eissn
0027-8424issn
1091-6490journal_volume
78pub_type
杂志文章abstract::The immunophilin-immunosuppressant complexes cyclophilin-cyclosporin A (CsA) and FKBP12-FK506 inhibit the phosphatase calcineurin to block T-cell activation. Although cyclophilin A, FKBP12, and calcineurin are highly conserved from yeast to man, none had previously been shown to be essential for viability. We find tha...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.12.5372
更新日期:1994-06-07 00:00:00
abstract::Selection is widely accepted as the principal force shaping phenotypic variation within populations. Its importance in speciation and macroevolution has been questioned, however, because phenotypic differences between species or higher taxa sometimes appear to be nonadaptive. Here, we use the quantitative trait locus ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.192360899
更新日期:2002-09-17 00:00:00
abstract::In the mammalian retina, extensive processing of spatiotemporal and chromatic information occurs. One key principle in signal transfer through the retina is parallel processing. Two of these parallel pathways are the ON- and OFF-channels transmitting light and dark signals. This dual system is created in the outer ple...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.24.14130
更新日期:1999-11-23 00:00:00
abstract::Purine nucleoside analogs modified by replacement of the nitrogen atom at the 3 position by a CH group give a characteristic circular dichroism curve that is not substantially modified by chemical substitution at the 8 position. Since it is rather well established that 8-substituted purine nucleosides are predominantl...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.7.2384
更新日期:1976-07-01 00:00:00
abstract::The human placental alkaline phosphatase gene has been cloned and reintroduced into mammalian cells. When a plasmid carrying the gene under control of the simian virus 40 early promoter (pSV2Apap) is transfected into a variety of different cell types, placental alkaline phosphatase activity can readily be detected by ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.17.6342
更新日期:1988-09-01 00:00:00
abstract::A mitochondrial gene from Saccharomyces cerevisiae encoding a hydrophobic membrane protein, subunit 8 of the F0/F1-type mitochondrial ATPase complex, has been functionally replaced by an artificial nuclear gene specifying an imported version of this protein. The experiments reported here utilized a multicopy expressio...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.7.2091
更新日期:1988-04-01 00:00:00
abstract::Regulation of IFN signaling is critical in host recognition and response to pathogens while its dysregulation underlies the pathogenesis of several chronic diseases. STimulator of IFN Genes (STING) has been identified as a critical mediator of IFN inducing innate immune pathways, but little is known about direct coreg...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1901090116
更新日期:2019-08-13 00:00:00
abstract::Murine embryonal carcinoma (EC) cells are refractory to infection by retroviruses because retroviral long terminal repeat (LTR) enhancers have little activity in EC cells. A previous report described the isolation of clonal EC cell lines that express the integrated neomycin-resistance gene (neo) linked to the Moloney ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.11.3748
更新日期:1987-06-01 00:00:00
abstract::The hepatic uptake of cholephilic organic anions is a carrier-mediated process. Three distinct proteins [bilitranslocase (BTL), sulfobromophthalein (BSP)/bilirubin-binding protein (BBBP), and organic anion-binding protein] have been isolated from the basolateral plasma-membrane domain of the hepatocyte. To investigate...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.17.8136
更新日期:1993-09-01 00:00:00
abstract::The liver provides for long-term energy needs of the body by converting excess carbohydrate into fat for storage. Insulin is one factor that promotes hepatic lipogenesis, but there is increasing evidence that glucose also contributes to the coordinated regulation of carbohydrate and fat metabolism in liver by mechanis...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0401516101
更新日期:2004-05-11 00:00:00
abstract::A photoreactive derivative of epidermal growth factor (EGF) has been used to identify and specifically label a membrane receptor for EGF on mouse 3T3 cells. Photoactivable EGF, labeled with 125I, was incubated with 3T3 cells and then photolyzed in situ to generate a nitrene capable of reacting with a wide variety of c...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.74.7.2790
更新日期:1977-07-01 00:00:00
abstract::Phytohormones have essential roles in coordinately regulating a large array of developmental processes. Studies have revealed that brassinosteroids (BRs) and abscisic acid (ABA) interact to regulate hundreds of expression in genes, governing many biological processes. However, whether their interaction is through modi...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0900349106
更新日期:2009-03-17 00:00:00
abstract::Mechanism of enzymatic conversion of a fatty acid to the corresponding alkane by the loss of the carboxyl carbon was investigated with particulate preparations from Pisum sativum. A heavy particulate preparation (sp. gr., 1.30 g/cm3) isolated by two density-gradient centrifugation steps catalyzed conversion of octadec...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.21.6613
更新日期:1984-11-01 00:00:00
abstract::The sodium/iodide symporter (NIS) mediates active I(-) transport in the thyroid-the first step in thyroid hormone biosynthesis-with a 2 Na(+): 1 I(-) stoichiometry. The two Na(+) binding sites (Na1 and Na2) and the I(-) binding site interact allosterically: when Na(+) binds to a Na(+) site, the affinity of NIS for the...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1607231113
更新日期:2016-09-13 00:00:00
abstract::Cyanobacteria, blue-green algae, are the most abundant autotrophs in aquatic environments and form the base of all aquatic food chains by fixing carbon and nitrogen into cellular biomass. The single most important nutrient for photosynthesis and growth is nitrate, which is severely limiting in many aquatic environment...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0602517103
更新日期:2006-06-27 00:00:00
abstract::The influence of the rare initiation triplet AUU on mRNA translation was investigated by comparing the activity of two pairs of model mRNAs that differ in the length of Shine-Dalgarno and spacer sequences. Irrespective of the initiation triplet (AUG or AUU), all mRNAs had similar template activity in vitro, but transl...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.9.4161
更新日期:1993-05-01 00:00:00
abstract::The increasing frequency of antibiotic resistance in hospital-acquired infections is a major public health concern that has both biological and economic causes. Here we develop conceptual mathematical models that couple the economic incentives and population biology of hospital infection control (HIC). We show that th...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0409523102
更新日期:2005-02-22 00:00:00
abstract::The discovery of high-temperature superconductivity in iron pnictides raised the possibility of an unconventional superconducting mechanism in multiband materials. The observation of Fermi-surface (FS)-dependent nodeless superconducting gaps suggested that inter-FS interactions may play a crucial role in superconducti...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0900469106
更新日期:2009-05-05 00:00:00
abstract::The AAA-ATPase thyroid hormone receptor interacting protein 13 (TRIP13), jointly with the Mad2-binding protein p31(comet), promotes the inactivation of the mitotic (spindle assembly) checkpoint by disassembling the mitotic checkpoint complex (MCC). This checkpoint system ensures the accuracy of chromosome segregation ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1515358112
更新日期:2015-09-15 00:00:00
abstract::We consider the sequential estimation of p, the probability of success in an infinite sequence of Bernoulli trials, when the loss incurred in stopping after n trials and estimating p by some function delta(n) of the first n outcomes is taken to be [Formula: see text] The loss due to error of estimation is thus the sym...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.72.1.191
更新日期:1975-01-01 00:00:00
abstract::Plant soil specialists contribute greatly to global diversity; however, the ecoevolutionary forces responsible for generating this diversity are poorly understood. We integrate molecular phylogenies with descriptive and experimental ecological data, creating a powerful framework with which to elucidate forces driving ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1409242111
更新日期:2014-10-21 00:00:00
abstract::Model organism studies have demonstrated that cell fate specification decisions play an important role in normal brain development. Their role in human neurodevelopmental disorders, however, is poorly understood, with very few examples described. The cerebellum is an excellent system to study mechanisms of cell fate s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1315024111
更新日期:2014-04-29 00:00:00
abstract::The molecular basis of pathogen clone emergence is relatively poorly understood. Acquisition of a bacteriophage encoding a previously unknown secreted phospholipase A(2) (designated SlaA) has been implicated in the rapid emergence in the mid-1980s of a new hypervirulent clone of serotype M3 group A Streptococcus. Alth...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0607669103
更新日期:2006-10-24 00:00:00
abstract::Two series of peptides that specifically bind to the extracellular domain of the alpha chain of the human interleukin-5 receptor (IL-5Ralpha), but share no primary sequence homology to IL-5, were identified from libraries of random recombinant peptides. Affinity maturation procedures generated a 19-aa peptide that bin...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.110053997
更新日期:2000-06-06 00:00:00
abstract::The feeling of being observed or merely participating in an experiment can affect individuals' behavior. Referred to as the Hawthorne effect, this inconsistently observed phenomenon can both provide insight into individuals' behavior and confound the interpretation of experimental manipulations. Here, we pursue both t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1301687110
更新日期:2013-09-17 00:00:00
abstract::In photosynthetic systems, the absorbed light energy is used to generate electron transport or it is lost in the form of fluorescence and thermal emission. While fluorescence can be readily measured, the detection of thermal deactivation processes can be achieved by the photoacoustic technique. In that case, the press...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.1.281
更新日期:1994-01-04 00:00:00
abstract::Cells obtained from normal human skin synthesize predominantly type I collogen in culture. Cells obtained from the skin of an infant with a severe form of osteogenesis imperfecta were found to synthesize as much type III as type I collagen. Decreased synthesis of type I collagen could explain the tissue fragility obse...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.72.2.586
更新日期:1975-02-01 00:00:00
abstract::The repair of DNA double-strand breaks (DSBs) requires open, flexible chromatin domains. The NuA4-Tip60 complex creates these flexible chromatin structures by exchanging histone H2A.Z onto nucleosomes and promoting acetylation of histone H4. Here, we demonstrate that the accumulation of H2A.Z on nucleosomes at DSBs is...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1504868112
更新日期:2015-06-16 00:00:00
abstract::Addition of antisense oligonucleotides to cell cultures has been used to specifically inhibit gene expression. We have investigated the mechanism by which oligonucleotides enter living cells. These compounds are taken up by cells in a saturable, size-dependent manner compatible with receptor-mediated endocytosis. Poly...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.10.3474
更新日期:1989-05-01 00:00:00
abstract::Studies to elucidate the mode of action of aldosterone have been carried out in the amphibian urinary bladder. The following previously reported hypotheses were evaluated: (1) aldosterone stimulates sodium transport by increasing the amount of sodium available to the sodium pump; (2) aldosterone enhances energy produc...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.64.1.330
更新日期:1969-09-01 00:00:00