Abstract:
:The copy number of plasmid ColE1 has been known to increase when the Hae II-C segment downstream from the replication origin is deleted. The presence of the 306-base-pair (bp) Hpa II region in the segment is sufficient for reduction of the copy number. Plasmids harboring the region express a trans-acting function that is responsible for the copy number reduction and synthesize a unique protein. A protein specified by the region is purified to near homogeneity and identified as the 63-amino-acid protein encoded by the Hpa II segment. The region, which includes segments 19-25 bp and 53-311 bp downstream from the start site of the primer RNA, is involved in determination of sensitivity to the inhibitory function. In vivo transcription of the galK gene, which is directed by the primer promoter in a segment inserted in front of the structural gene, is inhibited by a plasmid carrying the Hpa II region. The inhibition is strong when the promoter segment contains up to 135 bp downstream from the primer RNA start site, whereas it is weak when only the region up to 52 bp downstream is present.
journal_name
Proc Natl Acad Sci U S Aauthors
Som T,Tomizawa Jdoi
10.1073/pnas.80.11.3232subject
Has Abstractpub_date
1983-06-01 00:00:00pages
3232-6issue
11eissn
0027-8424issn
1091-6490journal_volume
80pub_type
杂志文章abstract::The three-dimensional organization of HLA antigens has been investigated by spectroscopic and immunochemical techniques. Measurement of the circular dichroism shows that in papain-solubilized HLA the heavy chain as well as the previously studied light chain (beta 2-microglobulin) consists predominantly of beta-pleated...
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.76.8.3844
更新日期:1979-08-01 00:00:00
abstract::The regulatory mechanisms underlying the uptake and utilization of multiple types of carbohydrates in actinomycetes remain poorly understood. In this study, we show that GlnR (central regulator of nitrogen metabolism) serves as a universal regulator of nitrogen metabolism and plays an important, previously unknown rol...
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.1508465112
更新日期:2015-12-22 00:00:00
abstract::The inositol 1,4,5-trisphosphate receptor (IP3R) in the endoplasmic reticulum mediates calcium signaling that impinges on intracellular processes. IP3Rs are allosteric proteins comprising four subunits that form an ion channel activated by binding of IP3 at a distance. Defective allostery in IP3R is considered crucial...
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.1409730111
更新日期:2014-09-23 00:00:00
abstract::We and other groups have recently reported the potentiation by ribonucleotide reductase inhibitors such as hydroxyurea of the anti-human immunodeficiency virus type 1 (HIV-1) activity of purine and pyrimidine 2',3'-dideoxynucleosides in both resting and phytohemagglutinin-stimulated peripheral blood mononuclear cells....
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.92.18.8333
更新日期:1995-08-29 00:00:00
abstract::The effect of alpha-latrotoxin from black widow spider venom upon guinea pig cerebral cortical synaptosomes is described. Plasma membrane potential (delta psi p), in situ mitochondrial membrane potential (delta psi m), Ca2+ transport, gamma-amino[3H]butyrate release, [3H]noradrenaline release, and synaptosomal ATP wer...
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.79.24.7924
更新日期:1982-12-01 00:00:00
abstract::URF13 is a mitochondrially encoded, integral membrane protein found only in maize carrying the cms-T cytoplasm. URF13 is associated with cytoplasmic male sterility, Texas type, and causes susceptibility to the fungal pathogens Bipolaris maydis race T and Phyllosticta maydis. URF13 is predicted to contain three transme...
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.91.17.8253
更新日期:1994-08-16 00:00:00
abstract::Object recognition is challenging because the same object can produce vastly different images, mixing signals related to its identity with signals due to its image attributes, such as size, position, rotation, etc. Previous studies have shown that both signals are present in high-level visual areas, but precisely how ...
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.1714287115
更新日期:2018-04-03 00:00:00
abstract::For a constant membrane potential, a predominantly inhibitory GABAergic synaptic response is shown to undergo long-term transformation into an excitatory response after pairing of exogenous gamma-aminobutyric acid (GABA) with postsynaptic depolarization or pairing of pre- and postsynaptic stimulation. Current- and vol...
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.89.24.11862
更新日期:1992-12-15 00:00:00
abstract::The prediction of binding sites and the understanding of interfaces associated with protein complexation remains an open problem in molecular biophysics. This work shows that a crucial factor in predicting and rationalizing protein-protein interfaces can be inferred by assessing the extent of intramolecular desolvatio...
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.0136888100
更新日期:2003-01-07 00:00:00
abstract::Aconitase (Aco1p) is a multifunctional protein: It is an enzyme of the tricarboxylic acid cycle. In animal cells, Aco1p also is a cytosolic protein binding to mRNAs to regulate iron metabolism. In yeast, Aco1p was identified as a component of mtDNA nucleoids. Here we show that yeast Aco1p protects mtDNA from excessive...
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.0703078104
更新日期:2007-08-21 00:00:00
abstract::Intracellular bacterial pathogens evade the bactericidal functions of mammalian cells by physical escape from their phagosome and replication into the cytoplasm or through the modulation of phagosome maturation and biogenesis of a membrane-bound replicative organelle. Here, we detail in murine primary macrophages 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.0601838103
更新日期:2006-09-26 00:00:00
abstract::We describe a fractionation and purification scheme for the Drosophila RNA polymerase II general transcription factors. Drosophila TFIIE, TFIIF, TFIIH, and RNA polymerase II have been purified to greater than 50% homogeneity from Drosophila embryo nuclear extracts. TFIID has been purified 80-fold and is not significan...
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.93.12.5788
更新日期:1996-06-11 00:00:00
abstract::In addition to guiding proteins to defined genomic loci, DNA can act as an allosteric ligand that influences protein structure and activity. Here we compared genome-wide binding, transcriptional regulation, and, using NMR, the conformation of two glucocorticoid receptor (GR) isoforms that differ by a single amino acid...
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.1316235110
更新日期:2013-10-29 00:00:00
abstract::The pH gradient (delta pH) across the membrane of bovine neurohypophysial granules was estimated by using the [14C]methylamine partition technique. The granule membrane showed high permeability to sugars such as sucrose or sorbitol and to cations. Granules suspended in sucrose medium showed an acidic internal delta pH...
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.79.2.476
更新日期:1982-01-01 00:00:00
abstract::A five-helix secondary structural model is proposed for eukaryotic cytoplasmic 5S rRNA. All available sequence data are consistent with this model including those from Chlorella 5S rRNA whose sequence is revised by data included here. Various architectural features of eukaryotic 5S rRNA are summarized in terms of this...
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.78.4.2150
更新日期:1981-04-01 00:00:00
abstract::To investigate the properties of metazoan replication origins, recent studies in cell culture have adopted the strategy of identifying origins using genome-wide approaches and assessing correlations with such features as transcription and histone modifications. Drosophila amplicon in follicle cells (DAFCs), genomic re...
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.1114209108
更新日期:2011-10-04 00:00:00
abstract::Hydrogen/deuterium exchange followed by trapping of the labeled species in the aprotic solvent DMSO has been used to elucidate structure in both the burst-phase molten globule-folding intermediate of apomyoglobin and in an equilibrium intermediate that models the kinetic intermediate. Precise estimates can be made of ...
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.0409538102
更新日期:2005-03-29 00:00:00
abstract::Nanoparticle-based experimental therapeutics are currently being investigated in numerous human clinical trials. CALAA-01 is a targeted, polymer-based nanoparticle containing small interfering RNA (siRNA) and, to our knowledge, was the first RNA interference (RNAi)-based, experimental therapeutic to be administered to...
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.1411393111
更新日期:2014-08-05 00:00:00
abstract::Landscape-scale reconstructions of ancient environments within the cradle of humanity may reveal insights into the relationship between early hominins and the changing resources around them. Many studies of Olduvai Gorge during Pliocene-Pleistocene times have revealed the presence of precession-driven wet-dry cycles a...
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.2004532117
更新日期:2020-10-06 00:00:00
abstract::Creatine kinase from rabbit muscle has been specifically labeled with a derivative of a nitroxide free radical on the two essential sulfhydryl groups, one per active site. The conformation in the environment of the enzyme-bound free radical and the change in conformation induced upon binding of the substrate, metal ad...
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.64.1.219
更新日期:1969-09-01 00:00:00
abstract::Infected-cell protein 4 (ICP4), the major regulatory protein specified by herpes simplex virus 1 in infected cells, binds to homologs of the sequence ATCGTCnnnnYCGRC (A sites, where n is any nucleotide, Y is a pyrimidine, and R is a purine) and to unrelated sequences for which no consensus sequence has been derived (B...
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.86.24.9808
更新日期:1989-12-01 00:00:00
abstract::Intermolecular energy transfer between appropriately chosen pairs of dyes can be used to induce or enhance banding patterns in human metaphase chromosomes. Energy transfer, calibrated by fluorometric studies on soluble dye.DNA complexes, can also be detected by photometric measurements on cytological preparations of m...
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.75.11.5650
更新日期:1978-11-01 00:00:00
abstract::Sugar compartmentation into vacuoles of higher plants is a very important physiological process, providing extra space for transient and long-term sugar storage and contributing to the osmoregulation of cell turgor and shape. Despite the long-standing knowledge of this subcellular sugar partitioning, the proteins resp...
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.0610278104
更新日期:2007-02-13 00:00:00
abstract::Functional imaging of the human brain is an increasingly important technique for clinical and cognitive neuroscience research, with functional MRI (fMRI) of the blood oxygen level-dependent (BOLD) response and electroencephalography or magnetoencephalography (MEG) recordings of neural oscillations being 2 of the most ...
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.0900728106
更新日期:2009-05-19 00:00:00
abstract::Ligand-specific molecular switches composed of RNA were created by coupling preexisting catalytic and receptor domains via structural bridges. Binding of ligand to the receptor triggers a conformational change within the bridge, and this structural reorganization dictates the activity of the adjoining ribozyme. The mo...
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.96.7.3584
更新日期:1999-03-30 00:00:00
abstract::The immunity protein to colicin A (Cai), which is constitutively expressed at a very low level in Escherichia coli strains, has been studied in recombinant plasmid constructs allowing expression of various immunity fusion proteins under the control of inducible promoters. The 13-amino acid NH2-terminal region of Cai w...
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.85.3.689
更新日期:1988-02-01 00:00:00
abstract::Many complex systems are organized in the form of a network embedded in space. Important examples include the physical Internet infrastructure, road networks, flight connections, brain functional networks, and social networks. The effect of space on network topology has recently come under the spotlight because of 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.1018962108
更新日期:2011-05-10 00:00:00
abstract::A climate/vegetation model simulates episodic wetter and drier periods at the 21,000-y precession period in eastern North Africa, the Arabian Peninsula, and the Levant over the past 140,000 y. Large orbitally forced wet/dry extremes occur during interglacial time, ∼130 to 80 ka, and conditions between these two extrem...
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.1917673117
更新日期:2020-02-04 00:00:00
abstract::Marine reserve theory suggests that where large, productive populations are protected within no-take marine reserves, fished areas outside reserves will benefit through the spillover of larvae produced in the reserves. However, empirical evidence for larval export has been sparse. Here we use a simple idealized coastl...
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.0907368107
更新日期:2010-10-26 00:00:00
abstract::Cyclooxygenase (COX)-2, a rate-limiting enzyme of prostaglandin (PG) production, is overexpressed in colorectal adenomas and adenocarcinomas, and its inhibition by nonsteroidal antiinflammatory drugs protects against colorectal cancer. Mechanisms of cancer promotion by COX-2 are not fully understood, but signaling thr...
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.1533221100
更新日期:2003-07-22 00:00:00