Abstract:
:The 23S twisted circular form of ColE(1) DNA has been isolated from Escherichia coli as a tightly associated DNA-protein complex with a sedimentation coefficient of approximately 24S. Treatment of this complex with pronase, trypsin, sodium dodecyl sulfate, Sarkosyl, or heat results in a conversion to a slower sedimenting form of 17S or 18S, as determined by centrifugation in neutral sucrose gradients. These treatments do not alter the sedimentation properties of noncomplexes supercoiled ColE(1) DNA even in the presence of the ColE(1)-protein complex. Electron microscopic analyses indicate that the decrease in sedimentation rate of the ColE(1)-protein complex after treatment with these various agents is largely owing to an induced transition of ColE(1) DNA from the supercoiled to the open circular state.
journal_name
Proc Natl Acad Sci U S Aauthors
Clewell DB,Helinski DRdoi
10.1073/pnas.62.4.1159subject
Has Abstractpub_date
1969-04-01 00:00:00pages
1159-66issue
4eissn
0027-8424issn
1091-6490journal_volume
62pub_type
杂志文章abstract::A central problem in understanding enzyme regulation is to define the conformational states that account for allosteric changes in catalytic activity. For Escherichia coli aspartate transcarbamoylase (ATCase; EC) the active, relaxed (R state) holoenzyme is generally assumed to be represented by the crystal structure o...
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.090087197
更新日期:2000-05-09 00:00:00
abstract::Granulocyte-colony stimulating factor (G-CSF) induces differentiation of M1 murine myeloid leukemia cells into mature granulocytes/macrophages and also causes accumulation of the cells in the G1 phase of the cell cycle. We examined, therefore, whether synchronization of M1 cells in the G1 phase could affect G-CSF-indu...
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.83.12.4317
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abstract::Corazonin is a highly conserved neuropeptide hormone of wide-spread occurrence in insects yet is associated with no universally recognized function. After discovery of the corazonin receptor in Drosophila, we identified its ortholog in the moth, Manduca sexta, as a prelude to physiological studies. The corazonin recep...
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.0305291101
更新日期:2004-04-27 00:00:00
abstract::PDZ domains are abundant protein interaction modules and typically recognize a short motif at the C terminus of their ligands, with a few residues in the motif endowing the binding specificity. The sequence-based rules, however, cannot fully account for the specificity between the vast number of PDZ domains and ligand...
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.1508931112
更新日期:2015-12-01 00:00:00
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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.85.23.9302
更新日期:1988-12-01 00:00:00
abstract::Using data from the Fragile Families and Child Wellbeing Study, this study examined the effects of the Great Recession on maternal harsh parenting. We found that changes in macroeconomic conditions, rather than current conditions, affected harsh parenting, that declines in macroeconomic conditions had a stronger impac...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 历史文章,杂志文章
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更新日期:2013-08-20 00:00:00
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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.89.20.9846
更新日期:1992-10-15 00:00:00
abstract::Epigenetics regulation plays a critical role in determining cell identity by controlling the accessibility of lineage-specific regulatory regions. In muscle stem cells, epigenetic mechanisms of how chromatin accessibility is modulated during cell fate determination are not fully understood. Here, we identified a long ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2004-11-23 00:00:00
abstract::The visual images in the eyes contain much more information than the brain can process. An important selection mechanism is feature-based attention (FBA). FBA is best described by attention filters that specify precisely the extent to which items containing attended features are selectively processed and the extent to...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2016-10-25 00:00:00
abstract::Noncatalytic carbohydrate binding modules (CBMs) are components of glycoside hydrolases that attack generally inaccessible substrates. CBMs mediate a two- to fivefold elevation in the activity of endo-acting enzymes, likely through increasing the concentration of the appended enzymes in the vicinity of the substrate. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2012-12-18 00:00:00
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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.031568098
更新日期:2001-01-30 00:00:00
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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.1506449112
更新日期:2015-10-13 00:00:00
abstract::Pyramidal cells in piriform cortex receive excitatory inputs from two different sources that are segregated onto adjacent segments of their apical dendrites. The present studies show that excitatory postsynaptic potentials (EPSPs) evoked by primary olfactory tract afferents that terminate on distal apical segments dis...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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abstract::During cardiac trabeculation, cardiomyocytes delaminate from the outermost (compact) layer to form complex muscular structures known as trabeculae. As these cardiomyocytes delaminate, the remodeling of adhesion junctions must be tightly coordinated so cells can extrude from the compact layer while remaining in tight 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.1606385113
更新日期:2016-07-05 00:00:00
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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.86.23.9389
更新日期:1989-12-01 00:00:00
abstract::Type IV pili (Tfp), which are key virulence factors in many bacterial pathogens, define a large group of multipurpose filamentous nanomachines widespread in Bacteria and Archaea. Tfp biogenesis is a complex multistep process, which relies on macromolecular assemblies composed of 15 conserved proteins in model gram-neg...
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.1618539114
更新日期:2017-06-20 00:00:00
abstract::The voltage-gated potassium (Kv) channel Kv1.5 mediates the I(Kur) repolarizing current in human atrial myocytes and regulates vascular tone in multiple peripheral vascular beds. Understanding the complex regulation of Kv1.5 function is of substantial interest because it represents a promising pharmacological target f...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2007-02-06 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1990-11-01 00:00:00
abstract::To study the similarity between a putative cloned mammalian release factor (RF) and tryptophanyl-tRNA synthetase (TRS), a recombinant rabbit RF fusion protein was expressed from prokaryotic expression vectors. Purified fractions of the fusion proteins were tested for TRS and RF activities. Addition of the fusion prote...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1988-09-01 00:00:00
abstract::The vaccinia virus early transcription factor (VETF), a heterodimeric protein composed of 82- and 70-kDa subunits, interacts with viral early promoters at both a sequence-specific core region upstream and a sequence-independent region downstream of the RNA start site. To determine the VETF subunit-promoter interaction...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1996-07-23 00:00:00
abstract::We report the results of crystallographic difference maps at 3.0-A resolution of complexes of metal-nucleoside triphosphates with aspartate carbamoyltransferase (carbamoylphosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2) from Escherichia coli. The complexes Gd3+-ATP, Al3+-ATP, and Gd3+-CTP bind to the allosteric...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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abstract::Site-specific recombination is responsible for a broad range of biological phenomena, including DNA inversion, resolution of transposition intermediates, and the integration and excision of bacteriophage genomes. Integration of mycobacteriophage L5 is catalyzed by a phage-encoded integrase with recombination occurring...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2000-07-05 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1994-02-15 00:00:00
abstract::The 33-amino-acid ankyrin motif comprises a beta-turn followed by two anti-parallel alpha-helices and a loop and tandem arrays of the motif pack in a linear fashion to produce elongated structures characterized by short-range interactions. In this article we use site-directed mutagenesis to investigate the kinetic unf...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2008-07-22 00:00:00
abstract::Treatment of cultured Hodgkin disease (HD) cells with neuraminidase results in decreased reactivity of monoclonal antibody VIM-D5 with its antigen, the X hapten, a fucosyl-N-acetyllactosamine. The other feature characteristic of HD cells is the expression of high levels of ectosialyltransferase activity. We present ev...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1986-05-01 00:00:00
abstract::Although the left and right human cerebral hemispheres differ both functionally and anatomically, little is known about the environmental or genetic factors that govern central nervous system asymmetry. Nevertheless, cerebral asymmetry is strongly correlated with handedness, and handedness does have a significant gene...
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.052494999
更新日期:2002-03-05 00:00:00
abstract::Intergroup conflict persists when and because individuals make costly contributions to their group's fighting capacity, but how groups organize contributions into effective collective action remains poorly understood. Here we distinguish between contributions aimed at subordinating out-groups (out-group aggression) fr...
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.1605115113
更新日期:2016-09-20 00:00:00
abstract::Bathorhodopsin-rhodopsin difference spectra of native 11-cis-rhodopsin and regenerated 9-cis-rhodopsin were measured at room temperature with a double-beam laser spectrophotometer after excitation at 532 nm. A detailed analysis of data obtained at 85 psec after excitation suggests that the bathorhodopsins generated fr...
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.80.7.1887
更新日期:1983-04-01 00:00:00